1、Sustainable bioenergy potentialin Caribbean small island developing statesDisclaimerThis publication and the material herein are provided“as is”.All reasonable precautions have been taken by IRENA to verify the reliability of the material in this publication.However,neither IRENA nor any of its offi

2、cials,agents,data or other third-party content providers provides a warranty of any kind,either expressed or implied,and they accept no responsibility or liability for any consequence of use of the publication or material herein.The information contained herein does not necessarily represent the vie

3、ws of all Members of IRENA.The mention of specific companies or certain projects or products does not imply that they are endorsed or recommended by IRENA in preference to others of a similar nature that are not mentioned.The designations employed and the presentation of material herein do not imply

4、 the expression of any opinion on the part of IRENA concerning the legal status of any region,country,territory,city or area or of its authorities,or concerning the delimitation of frontiers or boundaries.IRENA 2024Unless otherwise stated,material in this publication may be freely used,shared,copied

5、,reproduced,printed and/or stored,provided that appropriate acknowledgement is given of IRENA as the source and copyright holder.Material in this publication that is attributed to third parties may be subject to separate terms of use and restrictions,and appropriate permissions from these third part

6、ies may need to be secured before any use of such material.ISBN:978-92-9260-576-6Citation:IRENA(2024),Sustainable bioenergy potential in Caribbean small island developing states,International Renewable Energy Agency,Abu Dhabi.About IRENA The International Renewable Energy Agency(IRENA)serves as the

7、principal platform for international co-operation,a centre of excellence,a repository of policy,technology,resource and financial knowledge,and a driver of action on the ground to advance the transformation of the global energy system.An intergovernmental organisation established in 2011,IRENA promo

8、tes the widespread adoption and sustainable use of all forms of renewable energy,including bioenergy,geothermal,hydropower,ocean,solar and wind energy,in the pursuit of sustainable development,energy access,energy security and low-carbon economic growth and prosperity.www.irena.org www.irena.orgAckn

9、owledgementsThis report was developed under the guidance of Roland Roesch(Director,IRENA Innovation and Technology Center)and Ricardo Gorini.It was authored by Luiz A.Horta Nogueira,Eric A.Ocampo Batlle(Consultants)and Walter J.Sanchez(ex-IRENA);and Athir Nouicer and Chun Sheng Goh(IRENA).The report

10、 benefited from the reviews and inputs from IRENA staff:Arieta Gonelevu Rakai and Paul Komor.The report also benefited from valuable reviews and contributions from external experts:Ana Maria Majano(LEDS LAC),Seungwoo Kang(Total Energies).IRENA would like to thank the Government of Denmark for suppor

11、ting IRENA with the work that formed the basis of this report.Editorial and production support were provided by Francis Field and Stephanie Clarke,with design by Phoenix Design Aid.The report was edited by Fayre Makeig.For further information or to provide feedback:publicationsirena.orgCONTENTSABBRE

12、VIATIONS.6EXECUTIVE SUMMARY.71.INTRODUCTION.91.1.Socio-economic conditions in Caribbean SIDS.91.2.Energy situation in the Caribbean SIDS.121.3.Agriculture and land use in the Caribbean SIDS.151.4.Selection criteria .161.5.Sustainability and requirements of modern bioenergy systems.172.BIOENERGY POTE

13、NTIAL IN CARIBBEAN SIDS.182.1.Land available and appropriate for bioenergy production.202.2.Sugarcanes bioenergy potential.212.3.Scenarios for sugarcane bioenergy production.282.4.Oil palms bioenergy potential.322.5.Scenarios for oil palm bioenergy production.382.6.The bioenergy potential of municip

14、al solid waste.412.7.Waste-to-energy pathways.452.8.Scenarios for energy production from municipal solid waste.483.ENVIRONMENTAL,SOCIAL AND ECONOMIC IMPACTS.513.1.Decarbonisation .523.2.Job opportunities .543.3.Economic considerations and benefits.564.CONCLUSIONS.58REFERENCES.604|SUSTAINABLE BIOENER

15、GY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESFIGURESFigure 1 SIDS around the world,with the Caribbean SIDS highlighted.10Figure 2 Total energy consumption of the Caribbean SIDS,2018 and 2019 .12Figure 3 Final energy consumption for the Caribbean SIDS by source,2019.13Figure 4 Energy consu

16、mption patterns of the Caribbean SIDS.13Figure 5 Main types of land coverage in Caribbean countries.20Figure 6 Typical sugarcane biomass composition.22Figure 7 Proportion of sugarcane processing in the Caribbean SIDS.23Figure 8 Sugarcane production and harvested area in Cuba,2005-2019.23Figure 9 Sug

17、arcane production and harvested area in the Dominican Republic.24Figure 10 Sugarcane production and harvested area in Guyana.24Figure 11 Sugarcane production and harvested area in Haiti.24Figure 12 Sugarcane production and harvested area in Jamaica.24Figure 13 General diagram for sugarcane-based sug

18、ar and ethanol production(first generation).26Figure 14 Common set-up of a cogeneration system in the sugarcane agro-industry.27Figure 15 Potential ethanol supply in the four scenarios.30Figure 16 Potential sugarcane bioelectricity supply in the four scenarios.31Figure 17 Variation of oil content an

19、d the market price of different vegetable oil feedstocks.33Figure 18 Oil palm production and harvested area,Dominican Republic,2005-2019.34Figure 19 Schematic diagram for a palm oil mill.35Figure 20 Flow chart for the principal refining methods.37Figure 21 Potential biodiesel supply in the four scen

20、arios.40Figure 22 Potential bioelectricity supply in the Dominican Republic and Cuba.41Figure 23 Projected waste generation by region.43Figure 24 Waste generation rates in Latin American and the Caribbean .43Figure 25 MSW treatment techniques and their products .45Figure 26 A standard landfill with

21、a biogas collection system.46Figure 27 Production phases for typical landfill gas.47Figure 28 A typical MSW direct combustion(incineration)plant.48Figure 29 Potential power available for biogas generated from landfills in several Caribbean nations.49Figure 30 Potential energy available for incinerat

22、ion in various Caribbean countries.50Figure 31 CO2 emissions avoided due to the displacement of gasoline by sugarcane ethanol for scenarios C0(left axis)and C3(right axis).52Figure 32 CO2 emissions avoided due to displacement of diesel by palm oil biodiesel for scenarios C2and C3.53Figure 33 CO2 emi

23、ssions avoided due to displacement of fossil fuels electricity by bioelectricity fromsugarcane biomass(bagasse and straw),scenario C3.53Figure 34 CO2 emissions avoided due to displacement of electricity by bioelectricity from oil palm biomass,biogas and MSW.54Figure 35 Potential employment generated

24、 by bioelectricity production using sugarcane biomass.55Figure 36 Potential employment generated by bioelectricity production using oil palm biomass,biogas and MSW.55|5TABLESTable 1 Demography,economy and human development indicators of the Caribbean SIDS .11Table 2 Installed renewable energy capaci

25、ty in the Caribbean SIDS.14Table 3 Land use distribution in the Caribbean SIDS.15Table 4 Criteria and the countries selected for the assessment of bioenergy potential.16Table 5 Scenarios,technologies and key findings for sustainable bioenergy development in the Caribbean SIDS.19Table 6 Potential are

26、a for expanding bioenergy crops and the corresponding land percentage byCaribbean city.21Table 7 Edaphic characteristics of sugarcane .22Table 8 Sugarcane yield modelling data and results for Caribbean SIDS.25Table 9 Electricity and bagasse surplus in cogeneration schemes in sugarcane mills .28Table

27、 10 Description of the main parameters in the adopted scenarios.29Table 11 Current and potential sugarcane production in the Caribbean SIDS.30Table 12 Potential ethanol supply in the four scenarios for sugarcane biofuel(1 000 m3/year).31Table 13 Potential bioelectricity from sugarcane biomass(TWh/ye

28、ar).32Table 14 Edaphic characteristics of oil palm .32Table 15 Main parameters of the extraction stage of oil palm culture per tonne of FFB .36Table 16 Main parameters of the refining and transesterification steps of palm oil biodiesel production .37Table 17 Description of the main parameters in the

29、 adopted scenarios.39Table 18 Potential oil-palm-based biodiesel supply in Cuba and the Dominican Republic(kt/year).40Table 19 Potential bioelectricity supply from biomass palm oil in Cuba and the Dominican Republic.41Table 20 MSW generation by Caribbean country current data.44Table 21 Typical MSW c

30、omposition by Caribbean country.44Table 22 Typical LHVs of MSWs constituents .45Table 23 Municipal solid waste and landfill gas collection efficiency .49Table 24 Summary of environmental,social and economic impact indicators of modern bioenergydevelopment in selected Caribbean SIDS.51Table 25 CO2 em

31、issions avoided due to the displacement of gasoline by sugarcane ethanol for scenarios C0 and C3.52Table 26 Baseline cost data for investment forecasting.56Table 27 Investment required for sugarcane and oil palm mills for C3 scenario.57Table 28 Annual investment required for C3 scenario(assuming an

32、annual interest rate of 12%/8%and a 10-/15-year amortisation period)and ratio to GDP.57Table 29 Opportunities for,and barriers to,modern bioenergy in the selected Caribbean SIDS.596|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESABBREVIATIONSC0 business as usual scenarioC

33、1 business as usual with improved sugarcane yield scenarioC2 new framework without irrigation scenario C3 new framework with irrigation scenarioCEPCI Chemical Engineering Plant Cost Index CO carbon dioxidetCOeq tonnes of carbon dioxide equivalentCPO crude palm oilCPKO crude palm kernel oilCV calorif

34、ic valueEFB empty fruit bunch(from oil palm)EIA US Energy Information AdministrationFAO Food and Agriculture OrganizationFFB fresh fruit bunch(from oil palm)GDP gross domestic productGHG greenhouse gasHV heating valueHHV higher heating value LFG landfill gasLHV lower heating value MSW municipal soli

35、d wastePKS palm kernel shell POM palm oil millPOME palm oil mill effluentSDG Sustainable Development GoalSIDS small island developing statesWtE waste to energyUNITS OF MEASUREGW gigawattGWh gigawatt hourha hectarekg kilogrammekg/c/d kilogrammes/capita/daykha kilohectarekm2 square kilometrekt kiloton

36、nekWh kilowatt hourm3 cubic metreMha million hectareMJ megajouleMt million tonneMW megawatt MWh megawatt hour|7EXECUTIVE SUMMARYTo explore all possible options for sustainable bioenergy development in various regions,IRENA has conducted a series of studies focusing on different feedstocks,ranging fr

37、om energy crops to agricultural residues.Each study provides fact-based solutions suited to different regional contexts,with sustainability being the primary consideration to ensure bioenergy development aligns with ecological functions and socio-economic goals.Decision makers must be particularly m

38、indful of the limitations within the estimates provided,as further analysis considering local ecological and socio-economic contexts is required to strike a balance between maximising productivity and preserving ecological conservation efforts.This report provides a preliminary assessment of the bio

39、energy potential of six small island developing states(SIDS)in the Caribbean:Cuba,the Dominican Republic,Haiti,Jamaica,Trinidad and Tobago,and Guyana.These countries comprise about 94%of the regions area and 93%of its population.Three raw materials for the production of liquid biofuels(ethanol and b

40、iodiesel),and bioelectricity were considered:sugarcane,a well-known,high-yield crop developed across the region since the colonial period;oil palm,prevalent in only Cuba and the Dominican Republic;and municipal solid waste in all six countries.Across the six countries assessed,the land area that cou

41、ld be devoted to sustainable bioenergy crop production(considering legal restrictions and environmental guidelines)was estimated at 2.15millionhectares in 2019.Most of this was in three countries Cuba(68.7%),the Dominican Republic(12.8%)and Haiti(12%)and represents a fraction of each countrys land a

42、rea(14.2%in Cuba,5.7%in the Dominican Republic and 9.3%in Haiti).For the evaluation of bioenergy production potential in the countries considered in this study,just a share of this potential land was adopted.The potential annual production of sugarcane and oil palm as well as their conversion into b

43、iofuels(ethanol and biodiesel)and bioelectricity was evaluated assuming average yields in four technological scenarios,in addition to land use.For ethanol,considering the current availability of molasses(distilleries attached to mills),total ethanol production in the islands studied was estimated at

44、 303millionlitres,of which Cuba contributes 67.4%and the Dominican Republic 19.4%.When considering an expansion of sugarcane-cultivated areas and a state-of-the-art conversion process in an improved scenario(autonomous distilleries,improved sugarcane production),total potential ethanol production in

45、creases to 13.9billionlitres,of which 64.9%is from Cuba and 16.5%from Haiti.Biodiesel from palm oil was estimated at between 843 and 1 386 million litres;however,it is important to note that such preliminary estimates have uncertainties linked to water limitations and soil quality,among other factor

46、s,which could result in considerable reductions in the potentials estimated in this report.These levels of biofuel production,with the exceptions of Trinidad and Tobago and Jamaica,largely exceed the domestic demand for fossil fuel in the countries considered.Bioelectricity generation was evaluated

47、considering cogeneration schemes,in the case of sugarcane and oil palm,and the use of municipal solid waste(MSW)as a source of biomass for biopower generation.Thermal plants burning sugarcane bagasse and straw,along with the use of palm oils solid residue and biogas from the anaerobic treatment of t

48、he liquid waste of palm oil extraction,can generate about 20.6terawatt hours(TWh)and 2.4 TWh of power,much of it in Cuba and the Dominican Republic.The availability of MSW depends on 8|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESpopulation density as well as factors su

49、ch as waste composition and collection processes.In this study,it was estimated that biogas from the anaerobic conversion of MSW in sanitary landfills and the direct burning of fuel from MSW could generate 791and 1 860gigawatt hours(GWh)of electricity a year,respectively.Deploying modern,sustainable

50、 systems for the generation and utilisation of biofuel(and biopower)in selected SIDS could mitigate greenhouse gas emissions while offering significant socio-economic benefits,including:a.A reduction in emissions ranging from 0.71 to 25.7milliontonnes of carbon dioxide equivalent(MtCO2eq)per year,ab

51、out 56%of which is due to sugarcane-based bioethanol.b.The creation of between 5 000 and 306 000 jobs.c.Competitive liquid biofuel costs ranging from USD0.43 to USD0.41 per litre for ethanol and USD0.50 to USD0.45 per litre for biodiesel.To realise the total capacity estimated in the higher potentia

52、l scenario proposed for developing biofuels production systems in SIDS countries over a 10-year period,an annual investment equivalent to about 3%of the Gross Capital Formation observed in those countries is needed.|91.INTRODUCTIONIRENAs comprehensive approach to sustainable bioenergy development in

53、volves a series of studies that delve into diverse feedstock options across various regions.These studies meticulously analyse a spectrum of sources,ranging from dedicated energy crops to agricultural residues.The aim is to offer a nuanced understanding of bioenergy development possibilities tailore

54、d to specific regional contexts(especially in different continents)and also end-uses(e.g.biomass power and biojet fuels)(IRENA,2018,2019a,2019b,2019c,2021,2022a,2022b).Notably,the studies are rooted in scientific analysis based on factual data and evidence.By examining different feedstock types,thes

55、e studies provide a multifaceted view of potential bioenergy sources,considering their availability,feasibility,and impact on the environment.Especially,the emphasis on sustainability within these studies is paramount.A recent report has been released with a comprehensive analysis and discussion on

56、the sustainability aspects of bioenergy(IRENA,2022c).The focus is on ensuring that bioenergy development aligns with both ecological functions and socio-economic goals while contributing to the climate targets.These findings are intended to empower decision makers with the necessary information to p

57、ursue bioenergy development strategies in diverse regions worldwide.This particular report provides a preliminary assessment of the bioenergy technical potential of six Caribbean Small Island Developing States(Caribbean SIDS):Cuba,Dominican Republic,Haiti,Jamaica,Trinidad and Tobago,and Guyana.These

58、 countries correspond to about 94%of the total area in this region and 93%of the total population.Three sources of raw material,sugarcane,oil palm,and municipal solid wastes(MSW)were considered for bioenergy production,considering liquid biofuels(ethanol and biodiesel),and bioelectricity.The remaind

59、er of the section offers basic information on the six small island developing states(SIDS)whose present and prospective sustainable bioenergy potential were evaluated.The current situation of these countries is briefly described based on their socio-economic and energy indicators and current land us

60、e situation.1.1.SOCIO-ECONOMIC CONDITIONS IN CARIBBEAN SIDSThe SIDS were first recognised as a distinct group of developing countries at the June 1992 United Nations Conference on Environment and Development,held in Rio de Janeiro.The Caribbean is one of three geographic zones(Figure 1)in which the

61、worlds SIDS are distributed:the other zones are the Pacific,as well as the Atlantic,the Indian Ocean and the South China Sea(AIS).From a global perspective,the SIDS are a distinct group containing 39 states and 18 associate members of United Nations(UN)regional commissions.They are home to approxima

62、tely 65million people and face unique social,economic and environmental vulnerabilities(Thomas et al.,2020).10|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESFigure 1 SIDS around the world,with the Caribbean SIDS highlightedThree regions of small islanddeveloping statesTh

63、e CaribbeanCabo VerdeBahrainMaldivesSeychellesComorosMauritiusCubaBelize JamaicaHaitiDominicanRepublicSaint Kitts and NevisDominicaSaint LuciaSaint Vincentand GrenadinesBarbadosGrenadaGuyanaSurinameTrinidad and TobagoAntigua andBarbudaThe BahamasSingaporePalauVanuatuTongaFijiSamoaTuvaluKiribatiNauru

64、Marshall IslandsPapuaNew GuineaSalomonIslandsFederated States ofMicronesiaTimor-LesteGuinea-BissauSo Tom andPrncipeThe PacificThe Atlantic,Indian Ocean,Mediterranean and South China SeasSource:(Thomas et al.,2020).Note:SIDS=small island developing states.Disclaimer:This map is provided for illustrat

65、ion purposes only.Boundaries and names shown on this map do not imply any endorsement or acceptance by IRENA.While the SIDS differ significantly in terms of land area,systems of government,economic development and geographic characteristics,they share several particularities;this led the United Nati

66、ons to recognise them as a group with its own characteristics,including fossil fuel reliance,restricted industrial activity and limited economies of proportion(Atkinson et al.,2022).The Caribbean region is made up of nearly 7 000 islands,islets,reefs and cays spread over an extensive geographical ar

67、ea and encircled by the Caribbean Sea and the Atlantic Ocean.It is a tropical maritime region,with two climatic seasons per year wet and dry with temperatures varying between 25C in the winter and 32C in the summer(Fuller et al.,2020).The Caribbean SIDS are a distinct conglomerate of 26developing co

68、untries that face similar sustainable development challenges,including,for example,growing population,restricted resources,distance,vulnerability to natural phenomena,fragility to external shocks,disproportionate dependence on international trade and a fragile environment.According to the United Nat

69、ions Development Programme(UNDP,2022),the Caribbean SIDS include 16 UN members and 10 non-UN members/associate members of regional commissions(Table 1).The majority of these nations are islands(larger and small),while three are continental lands(Belize,Guyana and Suriname).The SIDS are home to more

70、than 39million inhabitants(91%in the five larger countries).Some countries are fully reliant on imported energy,whereas some export oil and natural gas(Aruba,Trinidad and Tobago and,more recently,Guyana)(Surroop et al.,2018).|11Table 1 Demography,economy and human development indicators of the Carib

71、bean SIDS CARIBBEAN SIDSSOVEREIGNTYSTATESSURFACE AREA(km2)POPULATION(1 000 PEOPLE)GDP PER CAPITA(USD1 000)HDIAnguillaUnited KingdomNon-member9114-Antigua and BarbudaIndependentUN member4228914.450.778ArubaNetherlandsNon-member18010530.25-BahamasUnited KingdomUN member13 87839328.610.814BarbadosIndep

72、endentUN member43028315.190.814BelizeIndependentUN member21 7593244.440.716BermudaUnited KingdomNon-member4 00064117.1-British Virgin IslandsUnited KingdomNon-member15130-Cayman IslandsUnited KingdomNon-member2646691.39-CubaIndependentUN member109 88411 2719.10.777CuraaoNetherlandsNon-member44415519

73、.7-DominicaIndependentUN member751726.530.742Dominican RepublicIndependentUN member48 19210 2777.270.756GrenadaIndependentUN member3441059.680.779GuyanaIndependentUN member214 9697956.960.682HaitiIndependentUN member27 75010 1741.180.51JamaicaIndependentUN member10 9912 7694.660.734MontserratUnited

74、KingdomNon-member1024.6512.38-Saint Kitts and NevisIndependentUN member2615417.440.779Saint LuciaIndependentUN member5391819.280.759Sint MaartenFranceNon-member548529.16-Saint Vincent and the GrenadinesIndependentUN member3891097.30.738SurinameIndependentUN member163 8205356.490.738Trinidad and Toba

75、goIndependentUN member5 1301 33715.380.796Turks and Caicos Islands United KingdomNon-member9483823.88-US Virgin IslandsUnited StatesNon-member3478738.130.894Source:(Surroop et al.,2018;UNDP,2022;World Bank,2022).Note:GDP=gross domestic product;HDI=Human Development Index;km2=square kilometre;SIDS=sm

76、all island developing states.In recent decades,the Caribbean SIDS have undergone rapid demographic,social,economic and political transformations.Since the early 2000s,the majority of this regions countries have made considerable progress in lowering poverty rates.The current median poverty in the Ca

77、ribbean SIDS is approximately 26%,but it is as high as 77%in Haiti,and 36%in Grenada and Guyana(FAO,2021).Human Development Index rankings underwent negative evolution in most Caribbean SIDS(Fuller et al.,2020).Likewise,economic development in the Caribbean SIDS has not been integrative,and assessme

78、nts of inequality,multi-dimensional progress and poverty reveal numerous differences and disadvantages(Scobie,2022).The majority of the Caribbean SIDS are middle-income countries.The per capita gross domestic product(GDP)ranges from USD1 180 in Haiti to USD38 130 in the US Virgin Islands(World Bank,

79、n.d.).Many Caribbean SIDS,which relied primarily on agricultural production,have switched to relying on tourism and service-related activities over the past two decades.Nevertheless,economic diversification continues to be a target to be achieved in several of this regions countries(Atkinson et al.,

80、2022).12|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATES1.2.ENERGY SITUATION IN THE CARIBBEAN SIDSThe Caribbean SIDS consumed 2 041petajoules(PJ)of energy in 2019;this is an increase of 2.76%over 2018(Figure2).Six countries account for nearly 90%of the regions primary ene

81、rgy consumption.Trinidad and Tobago stands out,with a 37.8%share of primary energy consumption,which is essentially due to its important petrochemical industry.The energy matrix of most Caribbean SIDS reveal the predominance of fossil fuels in the region.Fossil fuels represent 97%of the regions prim

82、ary energy consumption(petroleum derivatives 55%and natural gas 38%)(Figure 3).This picture,however,is strongly influenced by the high consumption in Trinidad and Tobago.Meanwhile,the modest share of renewable energies(2.56%)is noteworthy.Providing affordable energy access is one of several challeng

83、es faced by governments and communities in the Caribbean SIDS.The majority rely on imported fossil hydrocarbons(Figure 4,excluding Anguilla,Bahamas,Curaao and Sint Maarten,due to lack of data),essentially petroleum derivatives,for power generation and transportation.These energy sources are associat

84、ed with direct economic costs,provisioning risks and other indirect costs due to climate change(Atteridge and Savvidou,2019).In this sense,increased and potentially fluctuating combustible costs,along with increased transportation prices,antiquated grid infrastructure that leads to technical and com

85、mercial losses,and dependence of diesel generators,result in Caribbean SIDS experiencing a significant rise in power costs as compared to other nations(Raghoo et al.,2018).Figure 2 Total energy consumption of the Caribbean SIDS,2018 and 2019 00500600700800Trinidad and TobagoDominican Repu

86、blicCubaJamaicaSurinameHaitiGuyanaUS Virgin IslandsBarbadosArubaOther Caribbeans SIDS20192018PJ/ySource:(EIA,2022a)data from the base year,2019.Note:SIDS=small island developing states;PJ/y=petajoules/year.|13Figure 3 Final energy consumption for the Caribbean SIDS by source,20193%Coal39%Natural gas

87、55%Petroleum and other liquids3%Renewables and otherSource:(EIA,2022a).Note:SIDS=small island developing states.Figure 4 Energy consumption patterns of the Caribbean SIDS0%10%20%30%40%50%60%70%80%90%100%Antigua and BarbudaArubaBarbadosBelizeBermudaBritish Virgin IslandsCayman IslandsCubaDominicaDomi

88、nican RepublicGrenadaGuyanaHaitiJamaicaSaint Kitts and NevisSaint LuciaSaint Vincent and the GrenadinesSurinameTrinidad and TobagoTurks and Caicos IslandsUS Virgin IslandsCoalNatural gasPetroleum and other liquidsRenewables and otherBased on:(EIA,2022a)data from the base year,2019.Note:SIDS=small is

89、land developing states.Given the energy sectors direct relation with social,economic and environmental objectives,special attention on this sector must be included in the national development plans of most Caribbean SIDS.These priorities correspond to those of the Sustainable Development Goals(SDGs)

90、,especially SDG7 of the United Nations 2030 Agenda(UN,2021),the mitigation commitments made in the Paris Agreement through their respective Nationally Determined Contributions(Mohan,2022)and declarations like the SIDS Accelerated Modalities of Action Pathway(SAMOA)pathway,which emphasises access to

91、affordable and modern energy services,renewable energy and energy efficiency as key aspects of SIDS sustainable development strategies(UNDP,2016).Consequently,such goals will contribute to the reduction of energy dependence on imported sources,giving each nation greater autonomy and control over its

92、 energy market.The Caribbean SIDS have promising renewable energy potential,especially for solar radiation,wind,hydropower,geothermal and biomass.This potential,indicated by the installed renewable generation 14|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATEScapacity in t

93、his region(Table 2),favours the deployment of sustainable solutions.According to the platform(IRENA,2022c),the Caribbean SIDS had approximately 4.02gigawatts(GW)of installed renewable energy capacity at the end of 2020(excluding Belize,Guyana and Suriname).This installed capacity includes over 1 235

94、megawatts(MW)of solar photovoltaics,613MW of wind,1 057MW of hydropower and 1 113MW of bioenergy.This indicates that most Caribbean SIDS are theoretically capable of harnessing different alternative energy technologies that are well suited to the limited space and the regions soil and climatic chara

95、cteristics.Installed renewable energy capacity was highest for bioenergy(1.12GW),which represented 30%of the total capacity.The cogeneration systems of sugar mills accounted for 99.5%of this capacity,while biogas generation accounted for 0.5%.In summary,although the Caribbean SIDS have been increasi

96、ngly adopting renewable energy sources,essentially for generating electricity,national energy demand continues to rely on imported oil products,for all uses and especially for the mobility of people and goods,as indicated in Figure 4.Liquid biofuels have been considered in certain countries,such as

97、Jamaica,although with limited effective results.Table 2 Installed renewable energy capacity in the Caribbean SIDS(MW)CARIBBEAN SIDSSOLARWIND HYDROBIOENERGYAnguilla1.51-Antigua and Barbuda12.864.00-Aruba13.6030.00-2.00Bahamas2.54-Barbados68.881.16-Belize6.550.0256.9535.50Bermuda-British Virgin Island

98、s1.170.80-Cayman Islands13.70-Cuba257.9511.7571.90951.36Curaao16.1247.25-Dominica0.320.246.64-Dominican Republic697.62417.05625.1447.43Grenada3.600.080.00-Guyana6.650.082.3742.37Haiti2.610.0277.99-Jamaica92.5599.0030.0032.13Montserrat1.00-Saint Kitts and Nevis2.252.20-Saint Lucia3.84-0.18Sint Maarte

99、n-Saint Vincent and the Grenadines3.68-5.71-Suriname11.73-180.181.50Trinidad and Tobago4.000.01-Turks and Caicos Islands0.94-US Virgin Islands9.990.10-Based on:(IRENA,2022c).Note:MW=megawatt;SIDS=small island developing states.|151.3.AGRICULTURE AND LAND USE IN THE CARIBBEAN SIDSAgricultural activit

100、y accounts for less than 1%of the GDP of diverse Caribbean nations,although it continues to be a crucial sector of the economy of other nations such as Haiti,the Dominican Republic,Cuba,Jamaica and Trinidad and Tobago,where over 66%,50%,58%,40%and 10%of the national area,respectively,is designated a

101、s land for the use of this sector(Table 3).Agricultural activity contributes only 7%-17%of the GDP of the above countries,but it stands out due to its significant contribution to jobs(typically 10%-25%,and almost 50%in Haiti)(Fuller et al.,2020).Table 3 Land use distribution in the Caribbean SIDSCAR

102、IBBEAN SIDSLAND USE(km2)ALTCr(%AL)TMP (%AL)TF(%AL)PCr(%AL)PMP(%AL)FLAnguilla-55.00Antigua and Barbuda90.0033.75.25.511.144.481.80Aruba20.0075.911.612.4-4.20Bahamas140.0043.46.77.128.614.35 098.60Barbados100.0053.28.28.710.020.063.00Belize1 720.0039.76.16.518.629.112 882.10Bermuda3.0075.911.612.4-10.

103、00British Virgin Islands70.0010.81.71.814.371.436.20Cayman Islands27.005.60.90.918.574.112.72Cuba64 010.0022.31.921.210.244.432 420.00Curaao-0.70Dominica250.0018.22.83.068.08.0478.70Dominican Republic24 290.0027.44.24.514.649.321 360.10Grenada80.0028.54.44.750.012.5177.00Guyana12 412.5025.73.94.23.2

104、62.9184 245.00Haiti18 400.0044.244.244.244.244.23 504.10Jamaica4 440.0020.53.13.421.451.65 930.00Montserrat30.0050.67.88.333.3-25.00Saint Kitts and Nevis60.0083.30.00.01.715.0110.00Saint Lucia106.0014.03.39.669.43.7207.70Sint Maarten-Saint Vincent and the Grenadines70.0021.73.33.542.928.6285.40Surin

105、ame840.0056.08.69.26.019.0152 085.00Trinidad and Tobago540.0035.25.45.740.713.02 286.10Turks and Caicos Islands10.0075.911.712.4-105.20US Virgin Islands33.0020.73.23.46.166.7197.60Source:(FAO,2023)data from the base year,2019.Note:AL=agricultural land;FL=forest land;km2=square kilometres;PCr=land de

106、signated for permanent crops;PMP=land designated for permanent meadows and pastures;SIDS=small island developing states;TCr=land designated for temporary crops;TF=land with temporary fallow;TMP=land designated for temporary meadows and pastures.16|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL I

107、SLAND DEVELOPING STATESYet,as a preliminary assessment,looking at Table 3 shows that several Caribbean SIDS have sufficient land for expanding bioenergy crops when considering the share of land suitable and available,for instance,for temporary meadows and pastures,temporary fallow,and permanent mead

108、ows and pastures.These crops could play a crucial role in helping the Caribbean SIDS ensure affordable access to low-carbon energy for their inhabitants.There are multiple options to generate energy using biomass as a source.The most important crops for bioenergy production(traditional or modern)in

109、the Caribbean region are sugar cane(molasses,bagasse,straw and vinasse),cassava(peels,leaves,stems and cassava wastewater),coconuts(shell and husk),oil palm fruit(fibre,shell,empty fruit bunch and palm oil mill effluent),coffee(husk and spent coffee grounds)and cocoa(husk).One interesting potential

110、feedstock is sargassum seaweed which countries like Belize and Barbados are assessing its potential as a biofuel through research/pilot projects(Thompson etal.,2020).The disposal/use of sargassum is going to become of increased relevance for Caribbean SIDS as global warming persists.The bioenergy pr

111、oduced through solid waste processing(urban and industrial)can also be considered.1.4.SELECTION CRITERIA Table 4 describes the criteria that were adopted to define a set of Caribbean SIDS countries in order to assess their sustainable bioenergy generation potential.Table 4 Criteria and the countries

112、 selected for the assessment of bioenergy potential CRITERIARATIONALELIMITSCOUNTRIES SELECTED(IN ORDER OF SIZE/VOLUME/DEGREE BY INDIVIDUAL CRITERIONS)Land area of countryTo consider larger territories,with potentially more land available for biomass productionTotal area greater than 2 500km2Guyana,C

113、uba,the Dominican Republic,Belize,Jamaica,Trinidad and Tobago,HaitiPopulationTo consider a larger population,where bioenergy systems can promote more benefitsTotal population greater than 1millionCuba,Haiti,the Dominican Republic,Puerto Rico,Jamaica,Trinidad and TobagoNational energy consumptionTo c

114、onsider relevant energy markets,where the impact of bioenergy mattersA set of countries that represent at least 80%of the regional energy consumption of the Caribbean small island developing statesTrinidad and Tobago,the Dominican Republic,Puerto Rico,Jamaica,CubaSovereignty of countryTo consider st

115、ates that are able to define and implement energy programsAll independent statesThe Caribbean SIDS are a heterogeneous and diversified set of nations and states.The countries selected account for about 94%of the total area of this region,and about 93%of its population.Given the above criteria,the fo

116、llowing countries were selected for a detailed assessment of sustainable bioenergy potential:Cuba,the Dominican Republic,Jamaica,Trinidad and Tobago and Guyana.While Cuba,Dominican Republic,and Jamaica depend largely on energy imports for their domestic demand at same time that they have active suga

117、rcane agro-industry;previous attempts were made to adopt ethanol|17as fuel in Cuba and the Dominican Republic,and ethanol blends reached regular use(E10)in Jamaica.These are aspects that reinforce these countries interest in developing their own bioenergy production systems,and the selection of Trin

118、idad and Tobago,and Guyana deserves some justification(Gutirrez et al.,2020;Johnson et al.,2020).Trinidad and Tobago is well known as a significant exporter of natural gas,as well as the largest energy consumer in the Caribbean SIDS.Its inclusion in the detailed assessment was necessary to ensure th

119、at the selected countries represent at least 80%of the regions energy demand.Guyana,the largest country in the Caribbean SIDS,is opening promising frontiers of offshore oil production,but also has vast land for agriculture.Both Trinidad and Tobago and Guyana are traditional sugar producers since col

120、onial times.1.5.SUSTAINABILITY AND REQUIREMENTS OF MODERN BIOENERGY SYSTEMSAs indicated by the International Renewable Energy Agency(IRENA)in the World Energy Transitions Outlook(WETO 2022),limiting the global temperature increase will require bioenergy to play a decisive role.By the year 2050,susta

121、inable bioenergy production must grow from 34 exajoules in 2020 to 135 EJ in 2050(IRENA,2023).To reach these challenging goals,it is essential to pay strict attention to sustainability principles,as stressed in the biomass report by IRENA in 2022(IRENA,2022b):The production and use of bioenergy must

122、 be managed with care,however.Sustainability concerns about production and consumption are major issues in the bioenergy industry.They pose risks to investors and discourage policy makers from making bioenergy a major pillar of their strategies for reaching 1.5C targets.Other factors to consider inc

123、lude the potential competition between energy and other uses and the need to include appropriate sustainability constraints in particular,the extent to which land can be used to grow energy crops while preserving food security and biodiversity.Increased demand for bioenergy,as well as biomass as a c

124、hemical feedstock,will also influence supply.Some economic thresholds may also need to be applied.To ensure the sustainability of bioenergy,especially concerning the expansion of dedicated energy crops as explored in this study,its crucial to take into account the broader context of land management,

125、emphasising the interconnectedness between various land covers and uses on a landscape level.The goal is to strike a harmonious balance between the imperative for agricultural expansion and the preservation of vital ecological functions,such as safeguarding biodiversity,securing water supply and mai

126、ntaining soil health.Decision makers must be mindful of the inherent uncertainties and limitations within estimates provided in this study.This study intends to provide estimates for preliminary consideration,and they remain adaptable to evolving conditions in specific local contexts.18|SUSTAINABLE

127、BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATES2.BIOENERGY POTENTIAL IN CARIBBEAN SIDSFor selected members of the Caribbean SIDS,three raw material sources for bioenergy production are considered in this study:1.Sugarcane,considered for all countries,is a well-known crop developed si

128、nce the colonial period.2.Oil palm is considered only for Cuba and the Dominican Republic.3.Municipal solid waste(MSW),considered for all six countries.Among all the crops with bioenergy potential,adoption was the highest for sugarcane and palm,since they adapted well to the soil and climate conditi

129、ons in the region,besides having high productivity,in terms of volume of production per cultivated area and bioenergy per cultivated area.As highlighted in the previous chapter,although these crops offer high energy yields,an essential selection criterion,their adoption as energy sources and the sub

130、sequent energy development must follow strict sustainability criteria and consider biodiversity protection,and soil and water resource conservation,besides including production that benefits social welfare and is closely monitored and evaluated by the government.In this sense,within the scope of the

131、 global energy agro-industry,there are bad examples to avoid and good examples to be adopted.Assessing a nations potential to generate bioenergy from various crops involves determining how much land is accessible and the expected yield per hectare.The next sections present an assessment of land suit

132、able and available for sugarcane and oil palm,and the yield model adopted to estimate the annual feedstock production.For MSW,the annual potential production is linked to population and variables such as geographic factors and socio-economic level.To consider the conversion to bioenergy carriers(e.g

133、.ethanol,biodiesel and electricity),different technology scenarios are assumed for each feedstock,as described in Table 5,which also presents the key findings for each feedstock in this study.|19Table 5 Scenarios,technologies and key findings for sustainable bioenergy development in the Caribbean SI

134、DSSCENARIOTECHNOLOGYKEY FINDINGSSUGARCANEBusiness as usual(C0)A distillery annex was simulated with a conventional cogeneration system(a back pressure turbine and a low-efficiency boiler),based on the current sugarcane yield.In some countries,the potential expansion of sugarcane production is limite

135、d to preserve the forestry coverage,as observed in Guyana,whereas in other countries,the agricultural area is relatively limited,for example,in Trinidad and Tobago.The countries with the highest supply potential are Cuba,Haiti and the Dominican Republic,where over 21million tonnes(Mt)could be produc

136、ed annually.The availability of raw materials such as sugarcane molasses,which can be easily processed for producing ethanol,a biofuel seamlessly blendable with gasoline and compatible for use in conventional vehicles without modification,offers a favourable starting point to promote modern bioenerg

137、y.The utilisation of sugarcane bagasse and straw as combustibles in thermoelectric power plants has enormous potential to boost power production and broaden the energy mix of Caribbean small island developing states(SIDS).This could reduce fuel imports for electricity generation and improve electric

138、ity supply,contributing to carbon emissions mitigation.Business as usual with improved sugarcane yield(C1)The same system as above was simulated;however,improved yields were adopted(an increase of 60%over current production).New framework without irrigation(C2)An autonomous distillery was simulated

139、with a modern cogeneration system(condensation and extraction steam turbine),assuming sugarcane yield without irrigation.New framework with irrigation(C3)The same system as above was simulated,although assuming yield with irrigation.OIL PALMBusiness as usual(C0)A palm oil mill(without biodiesel prod

140、uction)and a cogeneration system(a back pressure turbine and a low-efficiency boiler)were assumed.This oil crop is produced and industrially processed only in the Dominican Republic,where 20kilohectares is available for producing 54kilotonnes(kt)of crude palm oil and 7.5kt of crude palm kernel oil p

141、er year.There is favourable potential to increase productivity.Considering the usual scale of the oil palm agro-industry,this study considered palm oil for bioenergy goals solely for the Dominican Republic and Cuba.In scenarios C2 and C3,Cuba and the Dominican Republic could immediately displace,res

142、pectively,26%-43%and 10%-17%of the overall diesel consumption using half of the potential crude palm oil production as feedstock to produce biodiesel.The utilisation of solid biomass from oil palm(fibre,shell and empty fruit bunch)as a combustible in thermoelectric power plants has excellent potenti

143、al to improve power production and transform the Dominican Republics and Cubas energy mix.Business as usual with improved yield(C1)The same industrial system as in the previous scenario and a higher-yield palm oil were assumed.New framework with average productivity(C2)A biodiesel plant annexed to t

144、he palm oil mill was adopted,with a modern cogeneration system(condensation and extraction steam turbine),a covered lagoon for effluent treatment and current average yield.New framework with improved productivity(C3)The same characteristics as in the C2 scenario were adopted but with higher oil palm

145、 yield.20|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESTable 5 ContinuedMUNICIPAL SOLID WASTE(MSW)Waste-to-energy via landfill gas(C1)The MSW treatment technique used in this scenario was landfill gas(LFG)recovery,with biomethane being burnt in alternative internal comb

146、ustion engines.In the SIDS countries,adequate final disposal of MSW is a major challenge:only a few nations dispose of their MSW in sanitary landfills.Open-air dumpsites are the prevailing MSW disposal mechanism(80%),which generates serious environmental issues.LFG-based energy generation potential

147、is the highest for Cuba and the Dominican Republic(over 313GWh per year and over 290GWh per year,respectively)since they are the most populous Caribbean islands and have the highest solid waste generation and energy consumption.Guyana,Haiti,Jamaica and Trinidad and Tobago have lower LFG-based energy

148、 generation potential;they could substitute 1.46%,7.57%,2.44%and 0.93%of their electricity consumption,respectively.The potential energy production from the direct combustion of MSW showed a substantial increase over potential LFG-based energy production for all the assessed Caribbean countries.Howe

149、ver,incineration is the most unlikely scenario,due to high investment and environment management costs.Waste-to-energy via direct combustion(incineration)(C2)For this scenario,direct combustion treatment coupled with a Rankine cycle,which uses a steam turbine to generate electricity,was used.2.1.LAN

150、D AVAILABLE AND APPROPRIATE FOR BIOENERGY PRODUCTIONAn area of 41.7millionhectares(Mha)of the Caribbean countries are being assessed.Within this mix,Guyana has the largest area,with 21.5Mha,followed by Cuba(10.9Mha),the Dominican Republic(4.8Mha),Haiti(2.7Mha),Jamaica(1Mha)and Trinidad and Tobago(0.

151、5Mha).Together,these countries represent more than 75%of the total area covered by the Caribbean SIDS.The areas of these countries are distributed across forestry and agriculture,are under inland waters and also include built-up areas and land used for aquaculture,for example.Figure 5 shows the dist

152、ribution of the area in each country.Figure 5 Main types of land coverage in Caribbean countries0%20%40%60%80%100%CubaDominicanRepublicGuyanaHaitiJamaicaTrinidad andTobagoAgricultural landForest landOther landArea under inland watersBased on:(FAO,2023)data from the base year,2019.|21The premises to

153、delimitate and quantify the potential areas for expansion were constructed based on legal restrictions and environmental guidelines,which guide how territories are occupied and utilised.The first restriction applied,based on data obtained from the Food and Agriculture Organization(FAO,2021),was the

154、exclusion of conservation units and indigenous lands,and urban areas.Areas under inland waters were subsequently excluded.Among the remaining areas,those whose agricultural land suitability is classified as inadequate(land under permanent meadows and pastures)and those that are currently occupied by

155、 agriculture(land under permanent crops)were disregarded,because no changes in land use are expected in these areas.Finally,from the remaining areas,those with land under temporary crops were also excluded.The result obtained indicates a potential area of 1.48Mha in Cuba,0.28Mha in the Dominican Rep

156、ublic,0.10Mha in Guyana,0.26Mha in Haiti,0.03Mha in Jamaica and 0.01Mha in Trinidad and Tobago for expanding the bioenergy crops frontier;most of this area already presents anthropic use and is classified as land under temporary meadows and pastures,and land with temporary fallow,as detailed in Tabl

157、e 6.It is worth noting that these lands,according to FAOSTAT,are hypothetically suitable for crop development(because these areas are classified as cropland);however,there is a probability that land of this type is in a state of degradation or in a degraded state(because they are lands with meadows,

158、pastures and fallows).Therefore,it is possible that there is some area in which the productivity levels noted in this study have not been reached and needs a specific evaluation through complementary studies.Note that the potential areas for expanding bioenergy production represent a modest fraction

159、 of the land areas of the Caribbean countries considered in the study.Moreover,these areas are within arable land,i.e.they possess the soil and climatic qualities for the optimal development of several energy crops.2.2.SUGARCANES BIOENERGY POTENTIALSugarcane,known for its high yields,is processed us

160、ing modern technology,presents interesting potential for bioenergy production and has undergone several modifications throughout history(Pereira et al.,2018).Sugarcane is a species of the grass family and a semi-evergreen.It is grown in regions roughly in the middle of the Earth(tropical and subtrop

161、ical zone)(Table 7).Commercial sugarcane varieties are complex hybrids,which are derived through intensive selective breeding between the species Saccharum officinarum L.and Saccharum spontaneum L.(OHara and Mundree,2016).Table 6 Potential area for expanding bioenergy crops and the corresponding lan

162、d percentage byCaribbean cityCARIBBEAN SIDSPOTENTIAL AREA FOR EXPANSION(kha)FRACTION OF TOTAL LAND AREA(%)Cuba1 479.9014.25Dominican Republic332.096.87Guyana101.710.51Haiti259.139.40Jamaica29.062.68Trinidad and Tobago7.951.55Source:(FAO,2023)data from the base year,2019.Note:kha=kilohectare;SIDS=sma

163、ll island developing states.22|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESTable 7 Edaphic characteristics of sugarcane EDAPHIC FACTORSSUGARCANEUNITClimateTropics and subtropics-Location33N and 33SLongitude and latitudeAnnual precipitation600-3 000mmTemperature25-32CDr

164、y season-MonthsSolar radiation18-36MJ/m2Wind18m/sPrincipal soil types for cultivationOxisols,aridisols,alfisols,argisols-Source:(Santos et al.,2015).Note:m2=square metre;MJ=megajoule;mm=millimetre;s=second.The main feature of sugarcane is its use in the production of sugars(mainly sucrose,glucose an

165、d fructose),which are concentrated in its stem.The aboveground part of the plant comprises the stem,green leaves and dry leaves.The aerial part of the plant contains a higher proportion of moisture than the part below ground.The aerial part thus has green leaves,whereas the portion below ground has

166、dry(or dead)leaves.Harvested stalks have about 70%moisture,and the dry matter is principally sucrose and lignocellulose,as indicated in Figure 6.Under favourable soil and climatic conditions,the marketable sugarcane crop yield is 80 000 to 110 000 kilogrammes per hectare(kg/ha);this is well below th

167、e theoretical maximum of approximately 470 000 kg/ha under optimal conditions (Cortez et al.,2018),but well over the 25 000 to 35 000 kg/ha yield seen under unfavourable conditions of water stress,deficient soils and inadequately advanced technology.Figure 6 Typical sugarcane biomass compositionStra

168、wDry and green leaves plus tips(typical production):140 kg per tonne of caneStalk compositionWater:65-70%Fibre:8-14%Sugars:-sucrose:10-17%-other:0.5-1%Tips and green leavesDry leavesStalksSource:(IRENA,2019a).Note:kg=kilogramme.|23The Caribbean has long been known as a region for sugarcane cultivati

169、on.Sugarcane is used as feedstock mainly for sugar production.Its subproducts,like bagasse and molasses,are used to produce steam/electricity(self-consumption of mills)and alcoholic liquor,respectively(Khan and Khan,2019).In 2019,according to the FAO(FAO,2023),over 25million tonnes(Mt)of sugarcane w

170、ere processed in 2019(Figure 7).Cuba is the undisputed leader in sugarcane processing in the Caribbean region(67%),followed by the Dominican Republic(19%),Haiti(6%),Guyana(4%)and Jamaica(3%).Cuba has historically been a sugarcane-producing nation.Prior to 1990,Cuba processed approximately 82Mt of su

171、garcane per year,with an average yield of 57 500kg/ha(Alonso-Pippo et al.,2008).Inappropriate policies,geopolitical shifts(Khan et al.,2019),degrading infrastructure and disasters caused by natural phenomena caused a 39%decline in Cubas average sugarcane yield in 2005,down to 22.4 t/ha.However,a ser

172、ies of improvement measures for sugarcane harvesting and processing(e.g.machinery renovation,complete automation of the manufacturing process and installation of better equipment,new investments in refineries to reduce steam consumption by thermal insulation of heat exchangers and piping)have led to

173、 an improvement in the average productivity of the countrys sugarcane agro-industry recently(36%,in 2019)(AZCUBA,2022),as shown in Figure 8.Figure 7 Proportion of sugarcane processing in the Caribbean SIDS67.41%Cuba19.41%Dominican Republic3.97%Guyana6.25%Haiti2.95%JamaicaBased on:(FAO,2023)data from

174、 the base year,2019.Note:SIDS=small island developing states.Figure 8 Sugarcane production and harvested area in Cuba,03004005006000.05.010.015.020.025.02005201020152019khaMtProduction(Mt)Harvested area(kha)Based on:(FAO,2023)data from the base year,2019.Note:kha=kilohectare;Mt=millio

175、n tonne.24|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESFigures 9,10,11 and 12 show the sugarcane production trend and the area harvested over the past 14 years for the Dominican Republic,Guyana,Haiti and Jamaica(FAO,2023).The cultivated area has grown since 2010 in the

176、 Dominican Republic.Sugarcane processing,however,has not kept pace with this growth.This is because the Dominican Republic has only four active sugar factories(Central Romana,Cristbal Colon,Barahona CAC and Azucarera Porvenir),which limits productivity(USDA GAIN,2022).For Guyana,a sharp decline in s

177、ugarcane production(36%)and cultivated area(37%)can be observed;this is due to socio-economic issues,labour shortages,unseasonable weather,a drastic decline in demand from the European Union and the permanent closure of several mills(Guyana Chronicle,2020).Jamaica shows the same trend as Guyana.Poli

178、tical changes,degrading infrastructure and disasters caused by natural phenomena led to a 20.6%decline in Jamaicas average sugarcane yield in 2019,down to 47.4 tonnes/ha(Figure 13).The situation is different for Haiti,as can be observed in Figure 11.Sugarcane production and area cultivated increased

179、 50%and 35%,respectively,in Haiti.This growth is related to diverse financial support through projects focused on strengthening the irrigation infrastructure and providing flood protection,and subsidies to promote technology transfer and sustainable agricultural practices,alongside the improvement o

180、f services such as phytosanitary controls and support for land regularisation measures(Banco Interamericano de Desarrollo,2022).Figure 9 Sugarcane production and harvested area in the Dominican Republic0204060801001201400.05.010.015.020.025.02005201020152019khaMtProduction(Mt)Harvested area(kha)Base

181、d on:(FAO,2023)data from the base year,2019.Note:kha=kilohectare;Mt=million tonne.Figure 10 Sugarcane production and harvested area in Guyana000.00.51.01.52.02.53.03.52005201020152019khaMtProduction(Mt)Harvested area(kha)Based on:(FAO,2023)data from the base year,2019.Note:kha=kilohectare

182、;Mt=million tonne.Figure 11 Sugarcane production and harvested area in Haiti05101520250.00.20.40.60.81.01.21.41.61.82005201020152019khaMtProduction(Mt)Harvested area(kha)Based on:(FAO,2023)data from the base year,2019.Note:kha=kilohectare;Mt=million tonne.Figure 12 Sugarcane production and harvested

183、 area in Jamaica05.00.20.40.60.81.01.21.41.61.82005201020152019khaMtProduction(Mt)Harvested area(kha)Based on:(FAO,2023)data from the base year,2019.Note:kha=kilohectare;Mt=million tonne.|25Finally,Trinidad and Tobago is not currently processing sugarcane industrially for energy since the

184、 economy is characterised by the availability of natural sources of fossil fuel such as oil and natural gas.However,sugarcane and its products,such as sugar,molasses and rum,which are rudimentarily cultivated and processed,are other important products for island trade,albeit on a smaller scale.Howev

185、er,financial incentives are expected to reactivate the agro-energy sector(Poltica Exterior,2019).Sugarcane production potential mainly depends on soil and climate conditions.Hence,this study estimated sugarcane yield as a function of precipitation and temperature by implementing Eq.(1),which conside

186、rs as the most sensitive parameters the frequency of warm days and the heat intensity on those days,and water available to sugarcane root systems in the soil(IRENA,2019a):(1)In the equation,IR is the irrigation ratio(IR=WI/HD),WI is water supplied annually by irrigation(millimetres,mm),DD is degree

187、days,for a base temperature of 20C(C-day),HD is annual hydric deficiency,for a 100centimetre soil depth(mm),and is the average yield of sugarcane stalks considering climate and irrigation(t/ha).Note that the amount of water supplied by irrigation should not exceed the water deficiency;irrigation sho

188、uld thus range from 0(no irrigation)to 1(irrigation at maximum level and no yield reduction)(IRENA,2019a).Table 8 summarises the data and modelled yield estimates for the Caribbean SIDS.The estimated yields are in the range observed in the Caribbean region and in other Central American and Caribbean

189、 countries(Cutz et al.,2013).The yield model developed above,as well as other similar simplified models implemented in large areas(Alejandra Moreno et al.,2018;Rudorff and Batista,1990;Teodoro et al.,2015),has limitations in the cases of specific harvest production(IRENA,2019a)and is also limited by

190、 changes in climatic conditions(mainly the increase in the frequency and intensity of extreme weather events,especially droughts)(Carvalho et al.,2015;Hussain et al.,2019).Agriculture scientists and decision makers,therefore,must work closely to mitigate the potential adverse effects of climate chan

191、ge on agriculture and improve sugarcane yields.In their efforts,they should follow through multi-disciplinary approaches,including,among others,continued development of new sugarcane cultivars through genetic improvement and molecular biology,and improved best management practices.Nevertheless,the m

192、odel described is a useful tool for estimating average yields,as required in this study.Table 8 Sugarcane yield modelling data and results for Caribbean SIDSCARIBBEAN SIDSSELECTED SITECO-ORDINATESDD(C-day)RAINFALL (mm)HD(mm)YIELD(t/ha)LATITUDELONGITUDENOT IRRIGATEDIRRIGATEDGuyanaGeorgetown648 N589 W

193、2 222.92 22611590.73102.23CubaSanta Clara2224 N7957 W1 776.41 30020077.7697.76Dominican RepublicSanto Domingo1829 N6955 W2 033.61 52516084.34100.34HaitiBarahona189 N714 W2 665.71 02431075.66106.66JamaicaMona3948 N11151 W2 980.81 28620689.21109.81Trinidad and TobagoPort of Spain1040 N6130 W2 688.02 1

194、0012594.38106.88Note:DD=degree days,for a base temperature of 20C(C-day);HD=annual hydric deficiency,for a 100-centimetre soil depth(mm);mm=millimetre;SIDS=small island developing states;t/ha=tonne/hectare.26|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATES2.2.1.Industrial

195、 schemes for the production of sugar,ethanol and powerBioethanol can be made comparatively easily from sugar than starchy feedstock.An aqueous solution of sugar can be fermented directly to an alcoholic solution,which can then be distilled to produce fuel-grade ethanol.This watery substance,known as

196、 molasses,is a co-product of sugar production.Therefore,in all countries where commercial production of ethanol from sugarcane has been introduced,it has started in the sugar mills with molasses as a raw material.Mills produce ethanol and sugar jointly,in percentages that vary based on the relative

197、prices.The initial processing phases for ethanol production are the same as for sugar production,as shown in Figure 13.If ethanol is produced simultaneously with sugar,the distillery is called“annexed”;and if all sugarcane juice is converted for ethanol,without sugar production,the distillery is cal

198、led“autonomous”.Conventional sugarcane-based sugar and ethanol production involves the common processes of cane collection,cane conditioning and juice extraction,which precede sugar and ethanol generation.The extracted juice is forwarded to purification,where impurities are filtered out,providing a

199、material that is suitable for the subsequent stages.Although most juice purification stages are similar for sugar and ethanol production,each technique has its particularities.In a sugar factory,crystallisation of sugar(molasses)produces a concentrated sweet solution,which is a fermentable by-produc

200、t.The sugarcane juice from the juice treatment phase of ethanol production is then mixed with molasses(when available)and fermented using yeast(which is recuperated and reutilised in the fermentation process).The ethanol-containing fermentation product(wine)is forwarded for distillation and dehydrat

201、ion.In the sugar factory,the juice is concentrated,crystallised,centrifuged and dried.Figure 13 General diagram for sugarcane-based sugar and ethanol production(first generation)StrawSteam,electricityAnhydrous EthanolSharedoperationsJuice treatmentJuice concentrationCrystallisationDryingSugarJuice t

202、reatmentBagasseJuice concentrationFermentationDistillation,rectificationDehydrationEthanol productionSugarcaneReceptionPreparationExtraction of sugarsCombined heat andpower generationSugar productionMolassesSource:(Dias et al.,2015).|272.2.2.Cogeneration from bagasse and sugarcane strawSugarcane fac

203、tories utilise three types of energy:thermal energy,for heating and concentration processes;mechanical energy,for milling and other mechanically driven systems;and electrical energy,for the operation of pumping,control and lighting systems.Sugarcane bagasse is used as a fuel to meet all these energy

204、 needs.It is used to produce electricity and heat via cogeneration.No external energy supply is required,and the surplus electricity generated can be sold through the power grid.Figure 14 depicts a common combined heat and power system in the sugarcane agro-industry.The high-pressure steam from burn

205、ing bagasse is fed to steam turbines to produce electricity(and to directly drive mills if there are no electric motors).Low-pressure steam emanating from the turbines helps meet the thermal energy needs.Generally,the power plants steam system is balanced,so that the steam supply covers the plants e

206、nergy needs.Large amounts of supplementary electricity can be produced for sale to the public grid,more specifically by reducing low-pressure steam consumption,optimising boiler efficiency and steam characteristics(by increasing pressure and temperature)and increasing the biofuel available to the bo

207、ilers(by incorporating sugarcane straw).Table 9 presents how the technical characteristics of the cogeneration systems steam boilers affect surplus production in the sugarcane mills either in the form of energy,that is,electricity,or bagasse.It presupposes the generation of 280kg of bagasse(at a moi

208、sture content of 50%)per tonne of sugarcane,low-pressure steam for the process at 2.5bar and the implementation of back pressure steam turbines.It also indicates the effect of using as fuel in the boilers 50%of the sugarcane straw available in the field which would mean an effective contribution of

209、70kg of this biofuel per tonne of sugarcane cut.Figure 14 Common set-up of a cogeneration system in the sugarcane agro-industryMake-upBagasseCondensateProcessDeaeratorDesuperheaterExpansionvalveMillTurbogeneratorSteam boilerLow-pressure steamLow-pressure steamHigh-pressure steamHigh-pressure steamSo

210、urce:(Seabra and Macedo,2011).28|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESTable 9 Electricity and bagasse surplus in cogeneration schemes in sugarcane mills STEAM BOILER PARAMETERSPROCESS STEAM CONSUMPTION(kg/tcane)SUGARCANE STRAW USETOTAL ELECTRICITY OUTPUT(kWh/tca

211、ne)ELECTRICITY SURPLUS(kWh/tcane)BAGASSE SURPLUS(kg/tcane)21bar,300C500No31.710.43342bar,400C500No55.425.45065bar,480C500No87.657.61365bar,480C350No101.671.6065bar,480C50050%169.7139.73365bar,480C35050%183.0153.00Source:(IRENA,2019a).Note:kg=kilogramme;kWh=kilowatt hour;t=tonne.It is worth pointing

212、out that the implementation of efficient cogeneration systems,with the sale of surplus electricity to public utilities,will be contingent on the existence of an appropriate regulatory framework.The electricity system must allow connecting sugar mill plants to the grid,promote such connection by mean

213、s of fair market prices(reflecting the combination of generation costs in the grid),foresee technical co-ordination for the grid to operate smoothly and protect both energy producers and utilities.The development of this normative framework in several countries(e.g.Brazil,Uruguay,Ecuador and the Dom

214、inican Republic)has yielded notable results,and sugarcane energy meets an essential portion of the countries needs.2.3.SCENARIOS FOR SUGARCANE BIOENERGY PRODUCTIONTo explore the situation in a context similar to the current one and with a potential breakthrough in the sugar-energy industry,the poten

215、tial supply of biofuel and electricity from sugarcane in the Caribbean SIDS was estimated for four scenarios,combining two scenarios for raw materials and two scenarios for processing.First,two reference scenarios were developed,corresponding to an annexe distillery;these were denominated C0(busines

216、s as usual)and C1(business as usual with improved sugarcane yield).In both cases,the objective is to represent,as faithfully as possible,the most widespread technology in the Caribbean sugarcane industry,which is(1)a traditional distillery annexe for sugar and ethanol production(ethanol derived from

217、 molasses in C0 and equal fractions of the juice 50/50 are utilised for ethanol and sugar production in C1;and(2)cogeneration systems with back pressure turbines for self-consumption(electricity for the system and steam to drive the mills).The practice of pre-burning in harvesting is considered,to e

218、liminate all the straw in the field.Typically,the mill uses only a fraction of the available bagasse(about 90%)as fuel in the cogeneration plant,so as to leave some bagasse to start boilers in the next harvest season.|29Table 10 Description of the main parameters in the adopted scenariosSCENARIOSSUG

219、ARCANE PLANTSCHARACTERISTICSC0Annex distillery,conventional cogeneration plant and current yield Current area used for cultivation:differs by country ha.y Current productivity:differs by country t/ha.y Ethanol productivity:15 l/t of cane Steam consumption:420 kg/t of cane Electricity surplus:10.4 kW

220、h/t of cane Mills powered by a steam turbine and a back pressure steam turbineC1Annex distillery,conventional cogeneration plant,improved yield Current area used for cultivation:differs by country ha.y Improved productivity:differs by country t/ha.y Ethanol productivity:32 l/t of cane Steam consumpt

221、ion:420 kg/t of cane Electricity surplus:10.4 kWh/t of cane Mills powered by a steam turbine and a back pressure steam turbineC2Autonomous distillery,modern cogeneration plant,yield without irrigation Potential area for expansion:differs by country ha.y Productivity without irrigation:differs by cou

222、ntry t/ha.y Ethanol productivity:85 l/t of cane Steam consumption:360 kg/t of cane Electricity surplus:123 kWh/t of cane Condensing/extraction steam turbineC3Autonomous distillery,modern cogeneration plant,yield with irrigation Potential area for expansion:differs by country ha.y Irrigated Productiv

223、ity:differs by country t/ha.y Ethanol productivity:85 l/t cane Steam consumption:360 kg/t of cane Electricity surplus:123 kWh/t of cane Condensing/extraction steam turbineNote:l=litre;kg=kilogramme;kWh=kilowatt hour;t=tonne;t/ha.y=tonne per hectare per year.On the other hand,in the improved scenario

224、s denominated C2(new framework without irrigation)and C3(new framework with irrigation),corresponding to an autonomous distillery bioenergy production(biofuel and bioelectricity)is prioritised.In both cases,the objective is to represent more efficient and mature technologies,which involve modern cog

225、eneration plants(condensing/extraction steam turbine),use of all the bagasse and 50%of the straw generated,and electrified mills.Table 10 summarises the main technological characteristics adopted by scenario.2.3.1.Current and potential sugarcane productionTable 11 presents sugarcane production in th

226、e Caribbean SIDS in 2019(FAO,2023)It also presents potential production assuming areas that could be utilised for expanding bioenergy crops and the country-wise estimated sugarcane productivity(see Table 12)for the studied scenarios.These values show the relevance of the current sugarcane industry a

227、nd the relative importance of land that could be available for expanding sugarcane production,utilising a comparatively modest portion of the national territory.It is important to note that scenarios C2 and C3 assumed the use of 75%and 60%of the area available for expansion in Cuba and the Dominican

228、 Republic,respectively;in the case of the other countries,100%of the available area was used.30|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESTable 11 Current and potential sugarcane production in the Caribbean SIDSCARIBBEAN SIDSC0 a C1C2C3POTENTIAL PRODUCTION INCREASE I

229、N RELATION TO C0(%)(103 t/y)C1C2C3Cuba17 000.030 253.386 312.2108 510.7178.0507.7638.3Dominican Republic4 895.910 386.013 985.716 639.0212.1285.7339.9Guyana1 002.31 616.49 228.410 398.1161.3920.71 037.4Haiti1 575.01 774.519 604.827 637.8112.71 244.71 754.7Jamaica744.21 397.32 592.53 191.1187.8348.44

230、28.8Trinidad and Tobago-750.2849.6-Source:a(FAO,2023)data from the year 2019.Note:C0=business as usual;C1=business as usual with improved sugarcane yield;C2=new framework without irrigation;C3=new framework with irrigation;SIDS=small island developing states.While restrictions in land use transforma

231、tion for sugarcane cultivation limit potential expansion in some countries,as observed in Guyana,in others,it is limited because the country is relatively small,for example,Trinidad and Tobago.The countries with the highest supply potential are Cuba,Haiti and the Dominican Republic,where over 21Mt c

232、ould be produced annually,even under the conservative hypotheses.2.3.2.Potential sugarcane ethanol supplyFigure 15 presents potential ethanol supply in the Caribbean SIDS for all production scenarios.As expected,this potential varies by sugarcane production.For the six countries selected,total ethan

233、ol production was estimated to range from 0.2millionlitres with Cuba and the Dominican Republic accounting for,respectively,67%and 19%,when considering the scenario of current availability of molasses(C0)to 14.2millionlitres,for the higher availability scenario(C3)with Cuba and Haiti accounting for,

234、respectively,65%and 16%,when considering an expansion of sugarcane cultivated areas and a state-of-the-art conversion process.This biofuel production represents a large share of the current consumption of gasoline,as shown in Figure 15;exceptions are Trinidad and Tobago and Jamaica,where the domesti

235、c demand for gasoline exceeds the biofuel demand.Figure 15 Potential ethanol supply in the four scenarios01 0002 0003 0004 0005 0006 0007 0008 0009 00010 000CubaDominican RepublicGuyanaHaitiJamaicaTrinidad and TobagoThousand m3 per yearC3C2C1C0Motor Gasoline consumption in 2019Note:C0=business as us

236、ual;C1=business as usual with improved sugarcane yield;C2=new framework without irrigation;C3=new framework with irrigation;m3=cubic metre.|31Table 12 Potential ethanol supply in the four scenarios for sugarcane biofuel(1 000 m3/year)CARIBBEAN SIDSMOTOR GASOLINE CONSUMPTION IN 2019 1 000 m3/y*C0 1 0

237、00 m3/yC1 1 000 m3/yC2 1 000 m3/yC3 1 000 m3/yCuba3672049687 3379 223Dominican Republic1 413593321 1891 414Guyana2371252784884Haiti36219571 6662 349Jamaica698945220271Trinidad and Tobago619006472*Source:(EIA,2022a)Note:C0=business as usual;C1=business as usual with improved sugarcane yield;C2=new fr

238、amework without irrigation;C3=new framework with irrigation;m3=cubic metre;SIDS=small island developing states.2.3.3.Potential biopower supply from sugarcane bagasse and strawThe utilisation of residual biomass(bagasse and straw)from sugarcane as a solid combustible in thermoelectric power plants pr

239、esents interesting potential to boost power generation and diversify the Caribbean SIDS energy matrix.This would reduce fuel imports for electricity production,contribute to better electricity supply and help mitigate carbon emissions,as indicated further.Figure 16 and Table 13 present the potential

240、 bioelectricity supply in the Caribbean SIDS for the four scenarios.Figure 16 Potential sugarcane bioelectricity supply in the four scenariosTWh per yearC3C2C1C0Non-renewable electricity consumption in 201416CubaDominican RepublicGuyanaHaitiJamaicaTrinidad and TobagoNote:C0=business as us

241、ual;C1=business as usual with improved sugarcane yield;C2=new framework without irrigation;C3=new framework with irrigation;TWh=terawatt hour.32|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESTable 13 Potential bioelectricity from sugarcane biomass(TWh/year)CARIBBEAN SIDS

242、NON-RENEWABLE ELECTRICITY CONSUMPTION IN 2019 TWh/y*C0 TWh/yC1 TWh/yC2 TWh/yC3 TWh/yCuba15.10.180.3110.6213.35Dominican Republic14.70.050.111.722.05Guyana1.00.010.021.141.28Haiti0.20.020.022.413.40Jamaica2.60.010.010.320.39Trinidad and Tobago8.2-0.090.10*Source:(EIA,2022a)Note:C0=business as usual;C

243、1=business as usual with improved sugarcane yield;C2=new framework without irrigation;C3=new framework with irrigation;SIDS=small island developing states;TWh/y=terawatt hour per year.Sugarcane-based bioelectricity could represent about 100%of Cubas,Guyanas and Haitis total electricity generation if

244、 a fraction of the fallow land(unused agricultural land),and meadow and pasture lands are used to expand sugarcane production.Otherwise,in the Dominican Republic,Jamaica and Trinidad and Tobago,bagasse and straw could represent,respectively,14%,15%and 1.2%of the countries total electricity generatio

245、n.Even with such lower contribution in these three countries,sugarcane provides an opportunity for their power sector to reduce its high dependence on natural-gas-and diesel-oil-based generation(EIA,2022a).2.4.OIL PALMS BIOENERGY POTENTIALElaeis guinensis(African oil palm),from which palm oil is ext

246、racted,is native to Africas tropical zone.However,Elaeis oleifera(a species from the Americas)is a native Latin American species distributed from northern Mexico to the Amazon,as shown in Table 14.Palm oil is common in the traditional diets of African and Latin American and Caribbean natives,yet it

247、is not the most widely consumed cooking oil.Table 14 Edaphic characteristics of oil palm EDAPHIC FACTORSOIL PALMUNITClimateTropical-Location10N and 10SLongitude and latitudePrecipitation2 000-4 000mm/yearTemperature20-34CDry season4MonthsSolar radiation14-21MJ/m2Winds25m/sPrincipal soil types used f

248、or cultivationArgisols,oxisols,vertisols-Source:(Corley and Tinker,2003).Note:m2=square metre;mm=millimetre;MJ=megajoule;s=second.|33Oil palm is a crop of immense economic importance for several tropical developing countries.It is a high-yield oilseed crop that is profitable and reasonably simple to

249、 grow,for large industrial plantations as well as family farmers.Two types of oil are extracted from this oil crop and marketed:mesocarp oil,known as crude palm oil(CPO,most commonly utilised in a transesterification reaction);and kernel oil,known as crude palm kernel oil(CPKO).Generally,4-5 t of CP

250、O and 0.4-0.5 t of CPKO can be obtained from one cultivated hectare of oil palm(Garcia-Nunez et al.,2016a).Globally,palm oil is one of the most important vegetable oils traded in the market,with an annual world demand of 165 Mt,and this demand is projected to double by 2050(Khatun et al.,2017).This

251、vegetable oil is frequently utilised in the food industry accounting for 50%of its applications,such as cooking oil and margarine.Additionally,50%of the oil serves as an oleochemical,replacing mineral oil derivatives in various industries like detergent,cosmetics,pharmaceuticals/nutraceuticals,plast

252、ics,and lubricants,as well as biofuels(FAO,2023).About 3,7 and 10 times more oil can be obtained from oil palm than coconut,rapeseed and soybean,respectively(Dey et al.,2021)its main contenders.These three crops also provide substantial non-oil products like coconut milk and soy protein meals as ani

253、mal feed.The market price of palm oil is also lower(Figure 17),and it is one of the main sources for biomass production,mainly in the form of residues(fibre,nuts,wastewater,etc.).The demand surge for palm oil as a biofuel source(biodiesel)is driven by escalating oil prices and the deadline to achiev

254、e the targets outlined in various environmental agreements and successive“green”or renewable energy replacement initiatives.Further,as the growing concern for consumer health and the environment continues,by-products and subproducts of the palm oil agro-industry have led to the emergence of new indu

255、stries(e.g.vitamins A and E,and other antioxidant health supplements from the oil;animal feed and organic fertilisers from the kernel;and sludge cakes from mill waste).Figure 17 Variation of oil content and the market price of different vegetable oil feedstocks6009008007001 0001 1001 2001 3001 40001

256、 0002 0003 0004 0006 0005 000PalmSoybeanCoconutRapeseedSunflowerPeanutPrice(USD/t)as May 2018Estimated oil content(kg oil/ha)Highest oil contentMinimum priceSource:(Dey et al.,2021).Note:ha=hectare;kg=kilogramme;t=tonne.34|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESTh

257、e palm oil agro-industry is a relevant producer of solid biomass residues.It produces roughly the equivalent of twice the quantity of CPO generated in a palm oil extraction plant(palm oil mill,POM).This solid biomass is composed of empty fruit bunches(EFBs),which are in a mass proportion of 22-25%of

258、 a fresh fruit bunch(FFB);fibres,which are in a mass proportion of 12-14%of an FFB;and palm kernel shell(PKS),which are in a mass proportion of 6-7%of an FFB(Ocampo Batlle et al.,2020).The energy yield of palm oil biomass(EFB,PKS and fibre)is about 100gigajoules/ha.year,equivalent to 37%of the energ

259、y contained in FFB,which is about 270gigajoules/ha.year(Ocampo Batlle et al.,2020).Nevertheless,much of these residues are meant to be returned to field as fertilisers and for soil regeneration.With careful management,this agro-industrial segment may have relevant energy potential.Moreover,it is con

260、sidered the main instrument of socio-economic advancement,especially in rural areas of Malaysia and Indonesia,but also in other tropical areas of the American continent(e.g.Colombia,Ecuador and Peru).The palm oil industry employs,directly and indirectly,about 2million people in Malaysia and about 5m

261、illion in Indonesia(Mat Yasin et al.,2017).Palm oil is currently produced and industrially processed only in the Dominican Republic,where 20kilohectares(kha)are producing 54kilotonnes(kt)of CPO and 7.5kt of CPKO annually(FAO,2021).As shown in Figure 18,the cultivated area for oil palm has grown at a

262、 rate of over 8%in the past 14 years.Such sustained growth has been achieved due,among other factors,to palm oils good profitability and the high market demand for oil palms products and by-products.But there exists immense potential to boost production by means of cultural and technological treatme

263、nts,since these indicators are currently below optimum.2.4.1.Oil palm yieldAs the expansion of oil palm plantations can lead to the displacement of biodiverse rainforests,addressing the growing demand for palm oil primarily relies on two main strategies:improved productivity and selective expansion

264、in degraded areas.Simply increasing productivity alone does not guarantee a reduction in deforestation,unless accompanied by supportive policies that are properly enforced.Nevertheless,enhancing productivity is a crucial step to alleviate pressure on the land and manage the environmental impact of p

265、alm oil production(Woittiez et al.,2017).Figure 18 Oil palm production and harvested area,Dominican Republic,2005-2019ProductionHarvested area15.015.516.016.517.017.518.018.519.019.520.020.522502602702802901234khaktBased on:(FAO,2023)data from the base year,2019.Note:kha=kilohectare;kt=ki

266、lotonne.|35For oil palm,the fundamental approach to crop modelling is reductionist in nature:a relatively simple model should be able to predict the behaviour of complex crops.Nevertheless,the large number of processes and reactions involved in plant growth can quickly give rise to very complex mode

267、ls that,in principle,could not be tested and are unlikely to be valid beyond the environment in which they were developed.In the literature review work developed by(Woittiez et al.,2017),the various research studies modelling oil palm productivity are synthesised,and it also points out the most impo

268、rtant limiting factors(photosynthetically active radiation,temperature,ambient CO2 concentration,water,nutrition and crops genetic characteristics).Most importantly,all these heavily rely on the nature of the business models,especially scale,ranging from independent small farmers to large-scale indu

269、strial plantations.2.4.2.Oil palm agro-industry:Crude palm oil and biodiesel productionMost commercial POMs typically process 3-60tonnes of FFBs per hour(with an extraction efficiency of 26%CPO per FFB),and they can process based on load or continuously depending on the FFB supply(Garcia-Nunez et al

270、.,2016a).Obtaining CPO from FFBs requires a series of processes,as shown in Figure 19.The initial stage involves sterilisation,where freshly harvested fruit bunches brought to the mill are subjected to high-pressure steam with a minimum delay to inactivate the lipolytic enzymes that cause the oils h

271、ydrolysis and cause the fruit to deteriorate.The subsequent stage is known as bunch stripping.It involves separating the fruit from the stems of the bunch by mechanical de-leafing.The separated and sterilised fruit is then sent to a digestion process,where it is reheated using extraction steam at a

272、temperature of no more than 90C.In this manner,the fruits are prepared for oil extraction by breaking the oil-bearing cells in the mesocarp and loosening the mesocarp from the nuts.CPO is extracted from the digested fruit macerate by means of a screw press without breaking the kernel.Once extracted,

273、the palm oil is clarified and purified.Figure 19 Schematic diagram for a palm oil millWeighingSterilisingStrippingScrew-pressingScrew-pressingClarifyingSeparatorSeparatorCrackingCycloneDryingPurificationPome treatment unitCPO refining unitPKO refining unitSteamSteamEFBPKSPPFNutsKernelsEfuentPKOPKCCP

274、OOilOilPOMESludgePressed PKOPPF+nutsPKS+kernelsSteamingand mashingPurificationand dryingBio-power plantWaste utilisationFFBOilSource:(Lee and Ofori-Boateng,2013).Note:CPO=crude palm oil;EFB=of empty fruit bunches;FFB=fresh fruit bunch;PKC=palm kernel cake;PKO=crude palm kernel oil;PKS=;palm kernel s

275、hell;POME=palm oil mill effluent;PPF=palm pressed fibre.36|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESThe liquid and nuts obtained are discharged from the auger machine.The oil obtained contains water,solids and diluted impurities in different quantities,which must be

276、 eliminated.Fibre traces in the pressed crude oil are first filtered out by screening the oil through a vibrating sieve;sand and dirt are allowed to settle out.On the other hand,the water is removed by decantation or centrifugation,and,finally,by vacuum drying.It should be noted that the clarified c

277、rude oil still contains about 0.1-0.25%moisture(Mohammad et al.,2021).This preserves oxidative properties and reduces the formation of soluble solids commonly called gums in trace quantities.The finished material is commercialised locally as CPO or can be refined further.The power for operating the

278、equipment of a POM is mainly obtained from solid biomass such as EFBs,PKS and Palm-pressed fibre generated by the subprocesses,which are considered waste.Table 15 summarises the ranges of values that can be obtained from oil palm processing.Before biodiesel production,crude palm oil has to be refine

279、d to reduce its acidity;i.e.the free fatty acids are eliminated,resulting in an oil that is composed of glycerides only.There are two distinct refining methods:chemical and physical(Figure 20).The physical method is the most used since it has a higher global yield,uses less chemicals and generates l

280、ess effluents.Finally,the refined oil is chemically processed to obtain biodiesel;the most used method for such processing is transesterification,which is carried out in the presence of an alcohol and an acidic or basic catalyst.Transesterification in industries commonly uses methanol as the alcohol

281、,while sodium hydroxide is the preferred alkaline catalyst,due to its low cost.The conversion of palm oil via transesterification with methanol and alkaline catalysis offers the most interesting processing route,due to its fast reaction kinetics and a high rate of conversion of refined oil to biodie

282、sel(methyl ester)at room temperature.Considerable crude glycerine production is nevertheless expected.The biodiesel thus produced is separated from the glycerol,washed in the first step with water and hydrochloric acid(pH 4.5)to neutralise the catalysts,centrifuged and dried to produce purified biod

283、iesel;the average conversion efficiency is 97%.The glycerine can be commercialised after an additional purification process involving distillation(Lai et al.,2012).Table 16 summarises the main operational parameters.Table 15 Main parameters of the extraction stage of oil palm culture per tonne of FF

284、B OIL EXTRACTION MEDIANMINMAXInputBoiler water(kg)534.29307.40761.18Steam(kg)1.030.821.27Electricity(kWh)104.301.89206.73Intermediate outputPalm oil mill effluent(kg)358.63303.20414.08Fibre(kg)130.0082.59177.41Shell(kg)55.0034.9375.06Final outputCrude palm oil(kg)192.81163.01222.61Empty fruit bunche

285、s(kg)220.00139.76300.24Biogas(Nm3)8.845.6212.10Sources:(Archer et al.,2018;Garcia-Nunez et al.,2016b;Lai et al.,2012).Note:FFB=fresh fruit bunch;kg=kilogramme;kWh=kilowatt hour;Nm3=normal cubic metre.|37Figure 20 Flow chart for the principal refining methodsNeutralisationDeodorisationEarth bleaching

286、Earth bleachingAlkalinedegummingHot waterdegummingDeacidification and deodorisationFractionation and filtrationChemical(alkaline)refiningPhysical(steam)refiningCPO/CPKOSteamSoapstockNaOHBleaching earthBleaching earthPhosphoric acidRBDPO/RBDPKOPalm stearinPalm oleinPFADRBDPO/RBDPKOPFADSource:(Lee et

287、al.,2013).Note:CPO=crude palm oil;CPKO=crude palm kernel oil;NaOH=sodium hydroxide;PFAD=palm fatty acid distillate;RBDPO=refined,bleached and deodorised palm oil;RBDPKO=refined,bleached and deodorised palm kernel oilTable 16 Main parameters of the refining and transesterification steps of palm oil b

288、iodieselproduction PARAMETER(INPUT/OUTPUT)MEDIANMINMAXInputCrude palm oil(kg)987.90835.201 140.60Water(kg)250.90145.30356.40Electricity(kWh)156.205.00307.40Methanol(kg)136.8093.20180.50Sodium hydroxide(kg)6.002.0010.00OutputBiodiesel(t)111Wastewater(kg)250.90145.30356.40Glycerol(kg)156.30102.60210.0

289、0Sources:(Archer et al.,2018;Garcia-Nunez et al.,2016;Lai et al.,2012).Note:kg=kilogramme;kWh=kilowatt hour;t=tonne.38|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATES2.4.3.Cogeneration from oil palm solid biomassLike the sugarcane agro-industry,the oil palm agro-industry

290、currently applies the concept of cogeneration.It uses as fuel the solid residues obtained from the palm oil extraction process.However,this is to meet the thermal energy demand for operating the industrial processes and to achieve electric self-sufficiency,not as a strategy to produce surplus power

291、and sell it to the grid,as happens in the sugarcane industry.The biomass conventionally utilised for this form of generation is obtained from complete burning of fibre(about 13%of the total processed FFB)and part of the shell(about 7%of the total processed FFB).Production of surplus electricity for

292、sale requires adopting modern high-pressure boilers and extraction-condensation turbines that have efficiencies of at least 85%and generate a high amount of energy consuming less fuel(Julio et al.,2021).According to data published by(Garcia-Nunez et al.,2016a),the operational characteristics of coge

293、neration systems range from 5MW to 40MW.The steam parameters of such systems are 20/65bar,with temperatures of 350/500C,and the systems generate about 75-160kilowatt hour per tonne(kWh/t)of FFB of excess electricity a rate expected when the palm oil mill is operating or stopped,respectively(and abou

294、t three or four times more than using a traditional back-pressure steam turbine system).2.4.4.Electricity from palm oil mill effluentAnaerobic digestion of palm oil mill effluent(POME)produces biogas in large quantities.It produces up to 28cubicmetres(m3)of biogas per tonne of POME,equivalent to 18.

295、2m3 of methane(CH4)and 9.8m3 of CO2(Ohimain and Izah,2017).The production of 1tonne of crude palm oil therefore releases about 52m3 of methane emissions if considering the production of 210kg of crude oil and the generation of 600kg of POME per tonne of fresh fruit brought into the extraction plant(

296、Aziz et al.,2020).Over the past few years,it has become widespread in Southeast Asia to produce electricity from biogas produced in the treatment of POME(IRENA,2022a).Each cubic metre of biogas can generate approximately 1.6kWh,considering a lower heating value(LHV)of 22.90megajoule(MJ)/m3 and 25%ef

297、ficiency.Latin American countries such as Peru,Honduras and Colombia have implemented clean production projects in oil extraction plants to capture the biogas produced in the POME treatment lagoons and generate electricity(Garcia-Nunez et al.,2016a).POME can be treated using multiple anaerobic diges

298、tion techniques;these include lagoon systems,upflow anaerobic digestion,anaerobic filtration,and anaerobic digesters and reactors of different configurations and designs.Global extraction plants widely use lagoons for POME treatment since they are cost-effective(Mohammad et al.,2021).2.5.SCENARIOS F

299、OR OIL PALM BIOENERGY PRODUCTIONLike the sugarcane industry,the potential supply of biofuel and electricity from oil palm in the Caribbean SIDS was estimated for four scenarios.Such scenarios were analysed only for Caribbean countries that have the edaphic disposition and where the oil palm culture

300、can be introduced and/or expanded;the Dominican Republic and Cuba were the cases for which these scenarios were analysed.First,two reference scenarios were developed,corresponding to palm oil extraction;these were denominated C0(Business as usual)and C1(Business as usual with improved yield).In both

301、 scenarios,the objective is to represent,as faithfully as possible,the most widespread technology in the Caribbean oil palm agro-industry,which consists of the use of traditional cogeneration plants with back pressure turbines to drive the generator and the mills.In the improved scenarios,denominate

302、d C2(new framework with minimum productivity)and C3(new framework with improved productivity),corresponding to a palm biodiesel plant,bioenergy production(biofuel and bioelectricity)is prioritised.In both scenarios,the objective is to represent more efficient and mature technologies,which involve mo

303、dern cogeneration plants(condensing/extraction steam turbine),use of all the fibre/shell and use of 50%of the EFB generated.It is important to note that scenarios C2 and C3|39assumed the use of 25%and 40%of the area available for expansion in Cuba and the Dominican Republic,respectively.Table 17 sum

304、marises the main technological characteristics adopted by scenario.2.5.1.Potential oil palm biodiesel supplyIn scenarios C2 and C3,Cuba and the Dominican Republic could immediately displace,respectively,26-43%and 11-17%of the overall diesel consumption using half of the potential CPO production as f

305、eedstock for biodiesel production.This would also produce interesting volumes for the global and/or national CPO,CPKO and glycerine markets 50 000 to 892 000tonnes of CPO,6 500 to 228 000tonnes of CPKO and 26 000 to 141 000tonnes of glycerine annually(Table 18&Figure 21).Table 17 Description of the

306、main parameters in the adopted scenariosSCENARIOSSUB-PLANTSCHARACTERISTICSC0POM,conventional cogeneration plant,current yield Current productivity:14 t of FFB/ha.y CPO productivity:180 kg/t of FFB CPKO productivity:23 kg/t of FFB Steam consumption:500 kg/t of FFB Electricity surplus:0 kWh/t of FFB M

307、ills powered by a steam turbine and a back pressure steam turbineC1POM,conventional cogeneration plant,improved yield Current productivity:16 t of FFB/ha.y CPO productivity:180 kg/t of FFB CPKO productivity:23 kg/t of FFB Steam consumption:500 kg/t of FFB Electricity surplus:0 kWh/t of FFB Mills pow

308、ered by a steam turbine and a back pressure steam turbineC2Biodiesel plant from CPO,modern cogeneration plant,covered lagoon treatment and minimum yield Minimum productivity:16.3 t of FFB/ha.y CPO productivity:180 kg/t of FFB CPKO productivity:23 kg/t of FFB Steam consumption:500 kg/t of FFB Electri

309、city surplus:160 kWh/t of FFB Biogas production:15 Nm3/t of FFB Condensing/extraction steam turbineC3Biodiesel plant from CPO,modern cogeneration plant,covered lagoon treatment and improved yield Maximum productivity:26.8 t of FFB/ha.y CPO productivity:180 kg/t of FFB CPKO productivity:23 kg/t of FF

310、B Steam consumption:500 kg/t of FFB Electricity surplus:160 kWh/t of FFB Biogas production:15 Nm3/t of FFB Condensing/extraction steam turbineNote:C0=business as usual;C1=business as usual with improved sugarcane yield;C2=new framework without irrigation;C3=new framework with irrigation;CPO=crude pa

311、lm oil;CPKO=crude palm kernel oil;FFB=fresh fruit bunch;ha.y=hectare per year;kg=kilogram;kWh=kilowatt-hour;Nm3=normal cubic metre;POM=palm oil mill;t=tonne.40|SUSTAINABLE BIOENERGY POTENTIAL IN CARIBBEAN SMALL ISLAND DEVELOPING STATESTable 18 Potential oil-palm-based biodiesel supply in Cuba and th

312、e Dominican Republic(kt/year)CARIBBEAN SIDSPRODUCTSC0(kt/y)C1(kt/y)C2(kt/y)C3(kt/y)CubaCPO-542.8892.4CPKO-138.7228.1Biodiesel-549.3903.1Glycerol-85.9141.2Dominican RepublicCPO50.557.6162.2266.7CPKO6.57.441.468.1Biodiesel-164.1269.9Glycerol-25.742.2Note:C0=business as usual;C1=business as usual with

313、improved sugarcane yield;C2=new framework without irrigation;C3=new framework with irrigation;CPO=crude palm oil;CPKO=crude palm kernel oil;kt=kilotonne;SIDS=small island developing states;y=year.Figure 21 Potential biodiesel supply in the four scenarioskt/yC3C2C1C002004006008001 000CPOCPKOBiodiesel

314、GlycerolCPOCPKOBiodieselGlycerolCubaDominican RepublicNote:C0=business as usual;C1=business as usual with improved sugarcane yield;C2=new framework without irrigation;C3=new framework with irrigation;CPO=crude palm oil;CPKO=crude palm kernel oil;kt/y=kilotonne per year.2.5.2.Potential bioelectricity

315、 supply from oil palm by-productsThe utilisation of solid biomass from the palm process(fibre,shell and EFB)as a source of chemical energy in thermal power plants has a significant potential to increase power output and diversify the Dominican Republics and Cubas energy mix(Table 19 and Figure 22).F

316、urther,biogas production from liquid effluents could potentially account for a proportion of the countries electricity consumption or natural gas consumption.Biogas production from liquid effluents could generate,respectively,3.44-5.65GWh and 2.90-4.76GWh of electricity annually,and 36 200 to 59 500

317、m3 and 29 300 to 48 100m3 of biogas annually in Cuba and the Dominican Republic.This should trigger a decrease in imports of foreign hydrocarbons for power generation and residential natural gas consumption,and improve the supply of these energies.|41Table 19 Potential bioelectricity supply from bio

318、mass palm oil in Cuba and the Dominican RepublicCARIBBEAN SIDSSURPLUS ELECTRICITYC2(GWh/y)C3(GWh/y)CubaBiogas from POME144.7238.0Solid biomass(fibre,shell and EFB)964.91 586.5Dominican Republic Biogas from POME43.271.1Solid biomass(fibre,shell and EFB)288.3474.1Note:C2=new framework without irrigati

319、on;C3=new framework with irrigation;EFB=empty fruit bunches;GWh=gigawatt hour per year;POME=palm oil mill effluent;SIDS=small island developing states.Figure 22 Potential bioelectricity supply in the Dominican Republic and CubaGWh per yearC3C202004006008001 6001 4001 2001 000CubaDominican RepublicSu

320、r.Ele.from biogasSur.Ele.from solid biomassSur.Ele.from BiogasSur.Ele.from solid biomassNote:C2=new framework without irrigation;C3=new framework with irrigation;GWh=gigawatt hour;Sur.Ele.=surplus electricity.Solid biomass from oil palm(fibre,shell and EFB)could represent,respectively,12.1%and 3,5%o

321、f Cubas and the Dominican Republics overall electricity consumption if these countries use 25%and 40%,respectively,of the pastureland(under temporary or permanent use)to expand oil palm production.Like sugarcane,oil palm provides opportunities for these countries to reduce their heavy reliance on di

322、stillate fuel oil and natural gas for power generation.This would also increase the share of renewable energy from 2.6%and 1.2%to 5.9%and 4.2%for Cuba and the Dominican Republic,respectively.2.6.THE BIOENERGY POTENTIAL OF MUNICIPAL SOLID WASTESince the last century,urbanisation and consumerism have

323、grown worldwide;this has triggered a concerning increase in solid waste generation.In fact,MSW,which results from the growing annual waste generation,is a serious concern for both advanced and emerging economies.The increase in waste generation can be linked 42|SUSTAINABLE BIOENERGY POTENTIAL IN CAR

324、IBBEAN SMALL ISLAND DEVELOPING STATESto economic progress,population growth and improved lifestyle,but it poses serious environmental and health hazards(Ilmas et al.,2021).Under this view,the management(collection and disposal)of MSW is one of the key challenges facing most nations today.Alternative

325、s to address such a concern must be environmentally friendly,legally and socially acceptable,technically feasible and economically affordable(Rodrigues etal.,2022).The Caribbean SIDS face increasingly difficult challenges in managing solid waste;an aggravating aspect is that inappropriate solid wast

326、e management poses hazards to society and the environment,as is the case in the studied SIDS countries.MSW is the type of waste typically produced by residential households,offices,businesses,hotels,schools and other institutional facilities.MSW mainly includes food waste,paper,plastics,metals,garde

327、n waste,cardboard and glass packaging waste.It may also contain demolition and construction debris and limited amounts of hazardous and chemical waste such as light bulbs,batteries,car parts,discarded medicines and chemicals(Hettiarachchi et al.,2018).The production of MSW is strongly correlated wit

328、h community size and per capita income.The composition of this waste varies widely and depends on multiple factors,including socio-economic level,and cultural and geographic factors.Food waste typically constitutes about 25-35%(in weight)of MSW,paper about 25-35%,plastics about 7-10%,ferrous metals

329、about 3-5%,non-ferrous metals about 0.5-2%,glass about 5-10%,yard waste about 10-15%and hazardous waste about 1-2%(Cayumil et al.,2021).In low-and middle-income countries,organic waste constitutes over 50%of the total MSW produced.In high-income countries,this proportion is approximately 32%.Recover

330、able materials vary between 10%in low-income countries and up to 50%in high-income countries.2.6.1.Waste generation and compositionWaste generation differs between economies.Developed countries(those with a GDP per capita above USD10 000 per year,according to the International Monetary Fund)tend to

331、have higher waste generation rates than less developed countries.Based on the 2018 World Bank report(What a Waste 2.0),2.01billiontonnes of MSW were generated globally in 2016,with the average waste generation rate being 740grammes/capita/day(g/c/d)(Figure 23).The projected MSW production until 2050

332、 stands at 3.4billiontonnes per year(Kaza et al.,2018).Waste generation in industrialised countries commonly ranges from 1 000 to 2 500g/c/d,whereas emerging countries typically have waste generation rates ranging from 500 to 1 000 g/c/d(Kumar and Samadder,2017).A total of 231Mt of waste were genera

333、ted in the Latin America and the Caribbean in 2016;per capita values ranged from 0.41 to 4.46kilogrammes/capita/day(kg/c/d),with an average of 0.99kg/c/d.Note that the nations with the steepest per capita indices are islands(Figure 24),probably due to waste generated by the tourism industry(Hettiarachchi et al.,2018)also because their accounting of all wastes generated may be more thorough than th