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8182019 Agricultural and Agro-Industrial Residues-To-Energy Techno-economic and Environmental Assessment in Brazil

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Research paper

Agricultural and agro-industrial residues-to-energy Techno-economic and environmental assessment in Brazil

Joana Portugal-Pereira Rafael Soria R egis Rathmann Roberto Schaeffer Alexandre Szklo

Energy Planning Program Graduate School of Engineering Universidade Federal do Rio de Janeiro Centro de Tecnologia Bloco C Sala 211 Cidade

Universit aria Ilha do Fund~ao 21941-972 Rio de Janeiro RJ Brazil

a r t i c l e i n f o

Article history

Received 20 October 2014

Received in revised form

30 June 2015

Accepted 7 August 2015Available online 27 August 2015

Keywords

Bioenergy

Agricultural residuesGIS mapping

Life cycle assessment

Climate change mitigationBrazil

a b s t r a c t

This study aims to quantify the environmentally sustainable and economically feasible potentials of agricultural and agro-industrial residues to generate electricity via direct combustion in centralised

power plants in Brazil Further the energy savings and greenhouse gas (GHG) reduction potential of replacing natural gas-based electricity by bioenergy have been assessed To this end a methodology hasbeen developed based on an integrated evaluation incorporating statistical and geographical informa-

tion system (GIS)-based analysis and a life-cycle-assessment approach Results reveal that the envi-ronmentally sustainable generation potential is nearly 141 TWhyear mainly concentrated in the South

Southeast and Midwest regions of the country Sugarcane soybean and maize crop residues are themajor feedstocks for available bioenergy On the other hand the economic potential is far lower ac-

counting to 39 TWhyear The total GHG mitigation is nearly 18 million tonne CO2e and could reach 64million tonne CO2e yearly if the technical potential is considered The gap between technical and eco-

nomic potentials implies that constraints to bioenergy are not related to a lack of resources but ratherassociated to economic logistical regulatory and political barriers

copy 2015 Elsevier Ltd All rights reserved

1 Introduction

The Brazilian power sector is on a knife-edge Historically thecountry has been a World leader on renewable energy with theshare of hydropower and bioelectricity making up approximately

79 of the countrys power generation portfolio in 2013 [1] How-ever year after year this contribution has been decreasing On theone hand on the demand side in the last decade electricity con-sumption increased two-fold up to 516 TWhyear partly due to therising quality of life of an emerging middle-class On the other

hand on the supply side the expansion of hydropower plant projects has been limited due to socio-environmental restrictions [23]Accordingly the Brazilian government has announced that theexpansion of large reservoir hydropower facilities will be con-

strained after 2025e30 [4] Reservoir hydro systems are equipped

with water storage facilities in order to control the water sent to

turbines allowing a variation in the amount of generated powerAlthough these systems are particularly capable to handle peakelectricity loads they raise environmental con1047298icts and socialconcerns especially in the Amazon basin and other environmen-tally sensible ecosystems Future projects might therefore be

limited to run-of-the-river technologies which imply reducedwater 1047298ooding and limited environmental impacts In these sys-tems water is streamed without a reservoir to a pipe that suppliesthe water turbine and then 1047298ows freely downstream While these

systems have low ecological and climate footprint run-of-the-rivertechnologies have limited capacity to provide 1047297rm energy to thegrid as the power generation oscillates considerably and is verymuch vulnerable to weather conditions [5]

The capacity of water storage in the dam reservoirs has beensteadily decreasing since 2008 (Fig 1) [6] Aggravating the situa-tion the country is facing a seriousdrought which as of April 2015reduced water level in reservoirs to an average of 31 of their total

storage capacity highlighting the vulnerability of the country to-wards extreme weather events [78] The autonomy of hydropowersystems expressed as the number of months that hydropowerplants can supply the countrys power demand excluding the

Corresponding author Energy Planning Program COPPE Universidade Federal

do Rio de Janeiro Centro de Tecnologia Sala C-211 CP 68565 Cidade Universitaria

Ilha do Fund~ao 21941-972 Rio de Janeiro RJ Brazil

E-mail addresses portugalpereirappeufrjbr joanaportugalgmailcom

(J Portugal-Pereira)

Contents lists available at ScienceDirect

Biomass and Bioenergy

j o u r n a l h o m e p a g e h t t p w w w e l s ev i e r c o m l o c a t e b io m b i o e

httpdxdoiorg101016jbiombioe201508010

0961-9534copy

2015 Elsevier Ltd All rights reserved

Biomass and Bioenergy 81 (2015) 521e533



dispatch of thermal power plants has been decreasing sharply tohistorically low levels While in late 1990s the water available incountrys reservoirs had capacity to supply 1047297rm power equivalentto consumption needs for about four months as of beginning of

2015 waterin reservoirs only guaranteed supply up to one month of demand

Forecasts predict that electricity consumption will double from2010 levels to 1100 TWh in 2035 [9] Following a business-as-usual

scenario this growth will partly be met with fossil fuel resources

[10] In recent years the Brazilian government has announcedaggressive investments to explore pre-salt oil and gas reserves and

even unconventional natural gas (shale and tight) This is seen as astrategy to increase the energy security of supply and to foster theresilience and resource diversi1047297cation of the power supply sector inparticular [11] Paradoxically in global terms increasing the share

of fossil fuels in the electricity generation portfolio results in higherGHG emissions with the possible consequence of inducing moresevere weather events which indirectly intensi1047297es the vulnera-bility of hydropower systems Thus the country is currently trap-

ped in a development vicious cycleRecent attention has been put on bioelectricity as a feasible

alternative to turn this tendency into a virtuous cycle It wouldsimultaneously diversify energy sources [12] reduce fossil-fuel

dependence [1314] and tackle climate change [1516] Althoughtraditional dedicated biomass has already a signi1047297cant expressionin the countrys power supply particularly based on sugarcanebagasse thermal power plants [17e20] there is a vast potential

from agricultural and agro-industrial residues which are currentlynot recovered Instead of being left on the farmland and slowlydecomposed (aerobically on the1047297eld or anaerobically in land1047297lls orcommon garbage dumps) releasing GHG emissions this valuable

feedstock could be collected and processed to generate electricityvia conventional thermochemical processes Assessing the bio-energy potential is therefore essential to characterise feedstocksboth qualitatively and quantitatively and to prospect the potential

substitution of fossil fuels and the associated reduction in GHGemissions

A small number of studies can be found in the literature thattouches this subject At the national level the technical potentialfor electricity generation from major agricultural crop residues andanimal manure has been estimated [2122] In more detail other

assessments quanti1047297ed the energy potentials of the main biomassresources in different regions of Brazil [23e26] A common limi-tation of these studies is the reliance on crude assumptions andsimple national statistics to quantify the potential of residue pro-

duction disregarding the economic and environmental limitations

of residue collection and processing Furthermore previous studiesare restricted to a speci1047297c area in the country or to a particular

technology Another downside is the lack of georeferenced statis-tical data in the bioenergy potential estimations As highlighted by[27] data about spatial distribution of biomass are needed tooptimise the ef 1047297cient use of resources

Aiming at overcoming this gap this study attempts to estimatethe technical environmentally sustainable and economic feasiblepotentials of agricultural and agro-industrial residues to generateelectricity via direct combustion in centralised systems in Brazil

Further it applies an integrated geographic information system(GIS)-based analysis to map residue availability and assesses howmuch bioenergy can replace fossil fuel resources and contribute to areduction in GHG emissions To this end a statistical analysis has

been conducted followed by a GIS mapping which identi1047297esoptimal locations for bioenergy generation centres under techno-economic and environmental constraints Then a life-cycleapproach has been undertaken to quantify the non-renewable

energy and GHG emission savings from replacing fossil-fuel-based electricity

This paper is structured as follows Section 2 presents the in-tegrated assessment applied in the study including key theoretical

principles about analytical quanti1047297cation of bioenergy with a sta-tistical based approach and GIS mapping as well as assumptionsapplied in the environmental assessment This is followed by Sec-tion 3 which discusses key results lessons learnt and limitation of

the study Lastly Section 4 outlines 1047297nal remarks and implicationsof the study to policy making

Fig 1 Regulation capacity of hydropower reservoirs in Brazil

Source Own elaboration based on [6]

J Portugal-Pereira et al Biomass and Bioenergy 81 (2015) 521e533522



2 Materials and methods

This study adopts a resource-based assessment that takes intoaccount the main characteristics of biomass feedstocks (Section 21)to estimate the technical environmentally sustainable and eco-nomic potentials for centralised electricity generation via direct

combustion in isolated systems (Section 221) Then resourceshave been mapped with a GIS tool considering logistic and eco-nomic limitations in order to estimate an indicator of economicbioenergy potential in rural areas in Brazil in terms of kWh

year km2 (Section 222) Lastly a Life Cycle Assessment (LCA) hasbeen conducted to evaluate fossil fuel savings and GHG reductionsof substituting fossil-fuel-based electricity by bioelectricity (Sec-tion 23)

21 Feedstock characterisation

Brazil one of the Worlds major agricultural producers [28]

generates signi1047297cant amounts of biomass residues in activitiesarising from harvesting and processing of agricultural productssuch as rice cotton sugarcane corn soybeans among others

Agricultural waste comes from the agricultural phase of the culti-

vation of certain species while agro-industrial residues result fromthe industrial processing of biomass

Much of the agricultural crops produced in Brazil are covered in

this work Among the most important crops in terms of the po-tential for use of residues one can cite sugarcane maize and soy-beans [28]

Three different solid residues are produced from sugarcane

processing straw (during farming) bagasse and 1047297lter cake (in theprocessing of ethanol) Currently the main source of agro-electricity in Brazil is sugarcane bagasse (operating capacity of 94 GW) due to the large sugarcane production for ethanol and

sugar and consequent production of this residue in sugar mills andethanol distilleries [29e31] It is noteworthy that recently otheragricultural and industrial sugarcane residues have been widely

studied for power generation Brazil already has in operation aconsiderable number of biomass power plants running on differentfeedstocks beyond sugarcane bagasse for example black liquor(17 GW) wood residues (371 MW) biogas (85 MW) rice husk(36 MW) charcoal (35 MW) elephant grass (32 MW) and palm oil

(4 MW) [29]Agricultural residues generated in the maize harvest which are

usually left in the 1047297eld are cobs stalks and stems (culms) and stoveIn this study we considered only stove for the purpose of energy

use with low heating value (LHV) moisture content residue-to-product ratio (RPR) availability of residues and annual availabilityfactor shown in Table 1

During the harvest of soybean the same residues as the maize

crop which are stalks stems and leaves commonly called soybean

straw are produced The harvester reaps the grain in the 1047297eld anddiscards these residues During processing products of highervalueadded such as bran and soybean oil are generated Due tothe

waste and by-products of soybean for food and feed supplemen-tation competition only straw from the harvest of soybeans wasconsidered as a residue

22 Waste-to-energy potential

221 Statistical quanti 1047297cation of agricultural and agro-industrial

residues

Bioenergy potential is constrained by the theoretical capacity of biomass production its environmental impacts and techno-economic viability [2728] The theoretical capacity de1047297nes the

maximum available bioenergy under biophysical and agro-

ecological conditions that hold down the growth of crops andresidues such as temperature solar radiation rainfall and soil

properties This potential is albeit limited by environmental con-straints as agricultural residues are important biome regulators Asdescribed by [53] residues create a buffer that mitigate impacts of rain and wind erosion agents and also protect soil from excessive

sunlight and evaporation Furthermore several studies ([5455])suggest that agricultural residues contribute to nutrient recyclingand organic matter 1047297xation and support microbial and macroinvertebrate activity The techno-economic viability on the other

hand refers to the fraction of the environmentally sustainablepotential available under technological possibilities logistic re-strictions and takes into account competition of other non-energyuses of residues Fig 2 lays out the schematic difference between

the biomass potentials under evaluation In this study the theo-retical geographic and technical potentials were implicitly quan-ti1047297ed while the environmentally sustainable and economicpotentials are presented in the following sections

Considering the techno-economic and environmental con-straints described above this study follows a bottom-up statisticalanalysis to determine the environmentally sustainable and techno-

economic feasible potentials of bioenergy from agricultural resi-

dues as follows

RP j frac14X

AiP iRPR jiESR j AR jLHV jh = 36 = 106 (1)

where

RP j agricultural residue potential (GWhyear)Ai agricultural area of crop i (hayear)Pi productivity of crop i (tonneha)

RPR ji residue of j to product i ratio () (see Table 1)ESR j environmentally sustainable removal rate of residue j ()AR j availability rate of residue j () (see Table 1)LHV j low heating value of residue j (MJkg) (see Table 1)

h conversion energy ef 1047297ciency of standalone biomass Rankinepower plant (18LHV ) [21]

Similarly the potential of bioelectricity from agro-industrialresidues has been evaluated as follows

RP k frac14X

eth AiP i ARkLHV kTHORNh = 36 = 106 (2)

where

RPk agro-industrial residue potential (GWhyear)Ai agricultural area of crop i (hayear)Pi productivity of crop i (tonneha)

AR k availability rate of residue k () (see Table 1)

LHV k low heating value of residue k (MJkg) (see Table 1)h conversion energy ef 1047297ciency of standalone biomass Rankinepower plant (18LHV ) [21]

Data regarding agricultural harvest area (Ai) and crop yields(Pi) have been collected in national database sets available from

the Brazilian Institute of Geography and Statistics (IBGE) underthe Municipal Agricultural Survey (PAM) for all Brazilian munic-ipalities (5565 in total according to the political division of 2010)in the baseline year 2010 [58] The biophysical and agro-ecological

limitations of residue generation expressed as the ratio of residuegenerated per product (RPR i) derive from the literature as shownin Table 1 Nonetheless it should be underlined that residue yieldvaries locally with agricultural practices climatic conditions and

crop yields As discussed in [59] empirical evidences suggest that

J Portugal-Pereira et al Biomass and Bioenergy 81 (2015) 521e533 523



residue yields increase up to a certain level and then remainconstant after that Thus 1047297eld surveys to measure residue pro-duction of crops under different climate conditions in severalBrazilian states would reduce the uncertainty of the conducted

assessmentThe environmental sustainable rate (ESR) assumes that part of

the residues needs to remain on the farmland to regulate theecosystem This factor should be evaluated locally based on speci1047297c

crops climate and soil conditions of agricultural land However to

the authors knowledge such data are not available for Brazilianconditions Thus in this study a conservative average removal rateof 30 has been considered (based on [384060e64]) The potentialof residues is further restricted by competition with other non-

energy uses and logistic constraints as described by the availablerate (AR i) as presented in Table 1

The power conversion ef 1047297ciency (h) of the standalone biomass-fuelled Rankine power plant is assumed to be 18 [21] which is

quite a conservative assumption Although more advanced

Table 1

Characterisation of evaluated residues

Resource Residue LHV a (MJkg)

Moisture contentb (wdbwdb)

Residue-to-product ratio(RPR)c

Availability of residues (wdbwdb)d

Annual availability factor()f

Sugarcane Straw 1862 600 022 65 50

Bagasse 1981 1039 022 10 50

Filter cake 1981 1039 002 10 50

Rice Straw 1722 863 154 100 50

Husk 1708 1000 026 30e

50Soybean Straw 2009 1400 201 100 40

Cotton Straw 2010 1400 281 100 25Cassava Peels and tops 2009 1400 111 100 50

Peanut Straw 2010 1400 252 100 33

Shell and husk 1898 799 056 70 33

Coffee Husk 1939 1075 059 50 58

Coconut Husk 2150 810 084 90 100

Shell 2009 1400 042 90 100

Palm oil Shell 1554 799 006 80 100

Fibres 1562 799 012 80 100

Empty fruit

bunches

1517 1200 020 100 100

Bean Stems and leaves 1433 900 145 30 50

Rye Straw 2008 820 161 100 25

Barley Straw 1968 881 148 100 25

Corn Stover 1867 565 153 100 50

Sorghum Straw 1906 704 190 100 25Oat Straw 1958 1232 154 100 25

Wheat Straw 1954 1124 155 100 33

a LHV of residues has been estimated based on the High Heating Value (HHV) proposed by [32e36] having as a reference the ultimate analysis of residues [37]b Based on [37]c Based on average Residue to product ratio (RPR) proposed by [38e49]d As for crop straws except for sugarcane straw an availability of 100 has been considered admitting that straw is currently left on the farmland without any recovery A

factor of 65 has been assumed for sugarcane straw taking into account the rate of farmland that is harvest mechanically with no open-air burning [50]e According to [51] 70 of rice husk are directly used in CHP units Only 30 of total residues are available for bioelectricity generationf Considering the period in months per year during which raw materials are available It is used as a proxy for the period in which the crop harvest occurs Based on [52]

Fig 2 Technical environmental sustainable and techno-economic potential of bioenergy generation

Source Adapted of [275657]




technologies are already availablein the market the heterogeneousmix of residues and their different physicochemical characteristics

are expected to reduce boiler ef 1047297ciency to lower levels than undernormal conditions

Table 2 summarises the key assumptions made to estimate thetechnical and environmentally-friendly and techno-economic po-

tentials Under the technical potential availability of residues hasno restrictions excepted for its use in other energy or non-energyprocesses as detailed in Table 1 As for the environmentally sus-tainable potential a theoretical constraint for removal of residues

has been applied due to environmental concerns about soil erosionand nutrient recycle as earlier explained The economic potentialon the other hand assumes that only biomass residues within acircle of 50 km radius [65] from power substations were able to be

converted into bioelectricity in centralised thermal power plants(see Section 222)

222 Spatial quanti 1047297cation

Bioenergy from agriculture and agro-industry has signi1047297canttechnical and environmentally sustainable potentials in speci1047297cmunicipalities of Brazil Although this knowledge is important it isnot enough to propose policies and projects that enable its energy

recovery Thus it is fundamental to quantify its economic andmarket potentials This paper assessed the economic potential byidentifying geographically the best suitable areas for the develop-ment of bioenergy power plants by applying a GIS analysis Themost important criteria to identify the suitability of areas of the

bioenergy power plants were the concentration of biomass resi-dues by area and their proximity to power substations For thispurpose the technical and environmentally sustainable potentialwas allocated to the respective rural areas of municipalities shape

1047297les with their division obtained from IBGE with datum SIRGAS2000 [58] Then shape 1047297les were converted to the ldquoGCS SouthAmerican 1969rdquo geographical coordinates by using the ldquoSouthAmerica Albers Equal Area Conicrdquo projection Rural areas of mu-

nicipalities were calculated using GIS tools An indicator of con-centration of residual biomass was calculated for everymunicipality by dividing the technical potential (GWhyear) by therespective area (km2) As a 1047297rst approximation to estimate the

economic potential it is considered in a conservative way that onlybiomass residues spread within a circle of 50 km radius areeconomically feasible to be used in centralised power plants closeto power substations where they could be connected Similar

studies evaluating economic potential for renewable energy sour-ces used similar approaches (40 km) as main criteria to restrict thetechnical potential [6667] A shape 1047297le containing coordinates of power substations was obtained from the Brazilian electricity

regulatory agency (ANEEL) [68] Using GIS tools a buffer of 50 kmradius was drawn around each power substation The area of each

municipality within the circle was then calculated to estimate theeconomic bioenergy potential

23 Environmental assessment

231 Goal and scope

In order to estimate the energy savings and avoided globalenvironmental loads of substituting marginal electricity generatedfrom natural gas by the proposed residue-based bioelectricity

system a comparative Consequential Life Cycle Assessment (CLCA)has been conducted in compliance with the ISO 14040-44 guide-lines [69] CLCA applied to the power generation system is a pro-spective modelling methodology that attempts to assess the side

effects of introducing a new power chain in the marginal powergeneration system It seeks to inform policy-makers about conse-quences on the environment of including new power generationchains in the overall power supply sector [70] This approach has

been extensively reviewed in the literature [71e73] and applied toevaluate the environmental impacts of energy chains [74] andagricultural systems [75]

The assessment has been developed by modelling input and

output energy and mass streams with the software SimaPro 801reg

[76] Each system is composed by sub-units which are segregatedin unitary processes All processes are interconnected through

inputoutput 1047298ows Results were then exported to an Excel inter-

face for further data analysis Environmental impacts have beenassessed based on depletion of fossil fuels and GHG emissionindicators

The model refers to the current Brazilian conditions of bioelectricity generation from agricultural and agro-industrialwastes The geographic coverage of the study encompasses po-tential of bioelectricity at a national level thus the scope of the

study refers to Brazils power generation Whenever national spe-ci1047297c data could not be collected for upstream processes the scopewas enlarged to include regional and worldwide coverage Evalu-ated systems focus on practices currently conducted in Brazil and

do not attempt to foresee any potential technological de-velopments Thus the technical scope of the model refers to currentpractices While other power generation options may be consid-

ered to convert biomass to electricity such as integrated gasi1047297ca-tion power cycles and organic Rankine cycles this study adopted arather conservative approach by selecting a thermodynamic cyclecommercially available with endogenous technology developed inBrazil

232 Functional unit

A functional unit has been selected in order to evaluate the

impacts of substituting marginal power by bioelectricity generatedfrom agricultural and agro-industrial wastes Thus a product basisfunctional unit has been selected to evaluate systems from a

downstream angle Impacts have been assessed per unit of gener-ated bioelectricity (GWhe) Then overall GHG mitigation potential

was estimated based on the environmentally sustainable and eco-nomic potential of bioelectricity generated in 2010

Table 2

Key assumptions of estimated technical and environmentally-friendly and techno-economic potentials

Estimated potentials Assumptions

Technical Energy recovery of biomass residues via direct combustion (biomass-fuelled Rankine power plant)Power conversion ef 1047297ciency (h) is assumed as 18

Availability of residues has no restrictions excepted for its use in other energy or non-energy processes (see factors in Table 1)

Environmentallysustainable

Only 30 of total residues are collected in order to protect the ecosystem from erosion and nutrient depletion

Techno-economic Only biomass residues spread within a circle of 50 km radius from the power substations are economically feasible to be used in centralised

power plants




233 System boundary and allocation

System boundaries of the bioelectricity generation system

include both upstream (collection transport and mechanical pre-treatment of residues) and downstream processes (operation of the power plant to generate bioelectricity) (Fig 3) Additionally theanalysis includes the ldquoCradle-to-Gate cyclerdquo of thermal power plant

infrastructure construction as well as the manufacture of agricul-tural machineries and equipment The reference systems describethe baseline pathways substituted by the bioelectricity generationsystem Thus the collection of agricultural residues displaces the

impacts of crop residues left on the 1047297eld mainly emissions of nitrous oxide (N2O) released by nitrifying and denitrifying micro-organisms that convert the nitrogen of aboveground residues intoN2O Further the recovery of agro-industrial residues displaces

disposal of waste in land1047297ll and consequent fossil fuel resourceconsumption and methane emissions Also the bioelectricitygenerated is assumed to substitute electricity of the national gridgenerated in a combined cycle gas turbine power plant (500 MW)

fuelled with onshore natural gas and avoided depletion of fossilfuel resources and corresponding GHG emissions

234 Inventory and data collection

The life cycle inventory has been developed in line with IPCCguidelines [77] and based on secondary data sets of EcoInvent li-braries [78] and tailored to re1047298ect the speci1047297cities of bioelectricity

parameters for technologies operating in Brazil (eg carbon andnitrogen content of fuels collection distance from farmland toprocessing unit energy conversion ef 1047297ciency and harvest ma-chinery) Impacts have been assessed in terms of GWP (100 years)

of GHGs While several air pollutants have a greenhouse effect themain anthropogenic drivers for radiative forcing in the bioenergysector are CO2 CH4 and N2O emissions [79] The aggregation of individual GHG 1047298ows into carbon dioxide equivalent (CO2e) has

been conducted as recommended by the IPCC in its 5th assessmentreport following the metrics CO2e frac14 CO2 thorn 34$CH4 thorn 298$N2O[79]

The following paragraphs brie1047298y describe the main assumptionsconsidered to model the bioelectricity and reference systems

2341 Bioelectricity system The bioelectricity system comprisesupstream and downstream processes Upstream processes include

collection of residues and transport from farmland to the powerplant unit (50 km distance as discussed in Section 222) Pre-

treatment operations are also taken into account which includesun-drying mechanical crunching and conditioning Farming ac-tivities have not been assessed as energy consumption and envi-ronmental loans were entirely allocated to crop products This

assumption admits that farmers only grow crops to collect mainproducts regardless of the agricultural residues produced The in-ventory employed derived from EcoInvent libraries [78]

Upstream processes include the operation of the biomass power

plant and emissions of methane and nitrous oxide from incompletecombustion of residues Carbon dioxide emissions released frombiomass combustion were not included in the inventory as biomasslife cycle is assumed to be carbon neutral ie carbon emissions

emitted during biomass combustion are equal to the atmosphericcarbon dioxide up taken during biomass growth

Emission factors were given by [77] and approximated to factorsof generic primary solid biomass combustion The energy required

and environmental loans of infrastructure of power plant compo-nents (boiler turbine and generator) have also been inventoried[78] Table 3 summarised key parameters of the bioelectricity sys-

tem assumed in the conducted LCA

2342 Reference systems

23421 Agricultural residues left on the 1047297eld As a baseline this

study assumes that agricultural residues are left on the 1047297eld toreduce impacts of erosion agents and increase organic matter andnutrient levels of the soil On the downside these abovegroundresidues also contribute to N2O emissions Their impacts are

signi1047297cantly lower than N2O emissions from inorganic and organicN-fertiliser application and open air burning practices Nonethe-less they should be also quanti1047297ed in accordance to IPCC Guide-lines of National Greenhouse Gas Emissions [77]

The N2O emissions of crop residues are released directly orindirectly via leaching and runoff from land during nitri1047297cationprocesses by nitrifying microorganisms that convert NH4

thorn to NO3

and realise N2O as a by-product as well as denitri1047297cation processes

by anoxic organisms that transform nitrogen oxides (NO3) into

atmospheric N2 via N2O Direct emissions are calculated as a frac-tion of 1 of the N-content of crop residues [77] Indirect emissionson the other hand are only relevant when runoff exceeds water

Fig 3 System boundary of the bioelectricity life cycle and reference systems




holding capacity of the soil or when 1047297elds are irrigated As local

data are not available a conservative approach has been adoptedassuming that leaching occurs in 30 of agricultural land in Brazilas suggested by Ref [77] Indirect emissions are estimatedassuming a fraction of 075 of the leached N-content of cropresidues

Emissions derived from synthetic and organic N fertilisers aswell as N mineralisation associated with loss of soil organicmatter resulting from management of soils are not considered inthe inventory as these impacts are associated to the agricultural

crop 23422 Agro-industrial residues in land 1047297ll The reference

pathway of agro-industrial residues assumes their disposal inland1047297lls Thedecomposition of these residues produces noteworthy

amounts of methane via anaerobic degradation of organic matter

This inventory assumes that the decomposable and degradableorganic carbon (50) is totally converted into methane

23423 Natural gas power plant The bioelectricity produced

is assumed to displace the generation of natural gas-based elec-tricity in a conventional combined cycle gas turbine of 500 MWcapacity with a conversion ef 1047297ciency of 45 The inventory ac-

counts for the direct impacts of the natural gas combustion as wellas the indirect loans of upstream processes from natural gasextraction and conditioning as well as infrastructure components[78] Direct emissions from carbon dioxide were estimated based

on the carbon content of natural gas (7487 wdbwdb) whereas

methane and nitrous oxide emission factors derive from defaultfactors of IPCC [77]

Table 4 reveals the overall life cycle inventory assessment of thebioelectricity and reference systems in terms of non-renewableenergy consumption and GHG emissions

3 Results and discussion

31 Waste-to-Energy potential

311 Environmentally sustainable potential of bioenergy

This sub-section presents the sustainable potential of bio-energy without considering economic limitations which will beaddressed in Section 32 Thus it refers to the amount of bioenergy

that could be recovered under environmentally sustainablepractices

Fig 4 reveals the spatial distribution of the bioenergy sustain-able potential of selected agricultural and agro-industrial residuesin 2010 Overall the sustainable potential is nearly 141 TWhyearwhich is equivalent to 27 of electricity generated in Brazil in 2010

This potential is mainly concentrated in the Southeast (33) South(28) and Midwest (27) which host major agricultural areaswhile the North and Northeast regions have limited bioenergypotential Nearly 88 of total potential derive from residues of

Table 3

Parameterisation of the bioelectricity system

Parameters

Upstream

- Collection distance 50 km rural road

- Transport type Generic rural truck powered with diesel

Speci1047297c consumption per km 1215 MJdiesel

Life time 30 years

Tonnage 5600 tonnesMaterial expenditure per vehicle 6 tonnessteel and 800 kgplastic

- Pre-treatment activities Sun-drying mechanical crunching and conditioningSpeci1047297c consumption of diesel 21 kJMJresidue

1

Material expenditure 183 tonnessteelMW1 and 10 tonnesHDPE MW1

Operating time yearly 1000 h year1

Life time 10 years

Ef 1047297ciency 99 (ww)

Downstream

- P ower plant o peration Mate rial expenditure 20 tonnessteel MW1 and 50 tonnesconcrete MW1


Life time 15 years

Net conversion ef 1047297ciency 18LHV

Table 4

Life cycle inventory of bioelectricity and reference systems

Non-renewable energy consumption (kgoil eq GWh1) CO2 (kgGWh1) CH4 (kg GWh1) N2O (kg GWh1) GHG(kgCO2e GWh1)

Bioelectricity system

Upsteam

- Collection 298Ethorn00 848Ethorn00 136E03 302E04 862Ethorn00

- Transport 107Ethorn00 262Ethorn00 353E03 263E04 282Ethorn00- Pre-treatment 184Ethorn01 626Ethorn01 147E 01 271E 02 757Ethorn01

- Infrastructure 283Ethorn00 112Ethorn01 175E02 361E04 119Ethorn01

Downstream

- Power plant op 000Ethorn00 000Ethorn00 540Ethorn02 720Ethorn01 398Ethorn04


Total 263Ethorn01 888Ethorn01 540Ethorn02 720Ethorn01 399Ethorn04

Reference systems

- Agricultural Residues left on the 1047297eld 000Ethorn00 000Ethorn00 000Ethorn00 255E01 759Ethorn01

- Agro-industrial residues in land1047297ll 409E04 000Ethorn00 287Ethorn02 000Ethorn00 975Ethorn03

- Natural gas-based electricity life cycle 192Ethorn05 449Ethorn05 802Ethorn00 800E01 445Ethorn05




Fig 4 Environmentally sustainable bioenergy potential

Fig 5 Estimation of economic bioenergy potential




sugarcane soybean and maize crops as these are the main agri-cultural cash crops in Brazil

312 Economic feasible potential

Fig 5 shows the areas in Brazil considered with economic po-tential to implement centralised bioenergy power plants within

50 km from power substations of the national power grid network(see Section 23) A further detailed 1047297gure which presents aregional zoom of each region in Brazil is presented in Annex A Theoverall economic potential of bioenergy in Brazil is estimated to be39 TWh which represents around 8 of total electricity con-

sumption in 2010 Considering an average annual availability factorof 50 (based on Table 1) a complete use of the estimated potentialmeans an installed capacity of around 9 GW Similarly to thetechnical potential major opportunities to implement economic

feasible bioenergy power plants are in the Midwest (22 TWh)Northeast (9 T Wh) and North (7 TWh) regions

Fig 6 details the area where are located the two municipalities

with the highest economic bioenergy potential of Brazil namelyPradopolis and Santa Luacutecia municipalities in S~ao Paulo State Asresults show in the Midwest and South regions there are munici-palities with more than 550 kWhyearkm2

However when an economic potential is concentrated in afew areas its deployment becomes much easier which is not thecase here Instead this amount of energy is spread within bigareas in Brazil This is precisely one of the barriers for increasing

biomass residues use in the country Nevertheless policies couldbe proposed to encourage cooperative schemes between agroproducers in rural areas Several authors point out the success of this kind of policies in Denmark [8081] where networks of agro

producers were organized in the form of cooperatives This typeof policy would be even more urgent in a large country such asBrazil lowering transaction costs and allowing for each agroproductive unit to supply its biomass residues to a large cen-

tralised power plant taking advantages of scale and access to1047297nancing

Other measure to be considered is the creation of new grids totransport electricity produced in the countryside to the main

transmission and distribution lines In addition considering thatmedium and small cities are close to some of the main residue

potentials identi1047297ed in this study advanced local grids withdistributed generation from biomass could also be proposedActually the economic and market potential of biomass residues tofuel small and medium power plants connected to distribution

lines andor local grids should also be evaluated in future workswith an approach similar to [82] or even including innovativetechnological options such as mini and micro generators based onOrganic Rankine Cycle (ORC) [83e87] The aim of the current study

was to focus on centralised power systems only

32 Environmental bene 1047297ts and energy savings

Table 5 lays out the yearly fossil fuel resources and GHG emis-

sion savings of introducing bioelectricity in the electricity genera-tion matrix replacing natural gas-based electricity and avoidingimpacts from agricultural waste left on the 1047297eld and agro industrial

waste disposal treatment in land1047297lls Considering the economicpotential of bioenergy environmental loads of bioelectricity gen-eration over a year are 156 million tonne CO2e and could reach563 million tonne CO2e when considering the environmentally

sustainable potential Impacts are mainly associated to the com-bustion of biomass in the power plants Although bioelectricityplants are admitted to have no net carbon dioxide emissions due tocarbon offsets during growth of biomass by photosynthesis pro-

cesses emission factors of methane and nitrous oxide emissions arehigh given the incomplete combustion in biomass-based powergeneration units

Avoided emissions on the other hand are nearly 1758 million

tonnes of CO2e emissions Savings are mainly related to down-stream processes ie avoiding combustion of natural gas togenerate electricity The impacts could be further minimised up to6363 million tonnes of CO2e emissions if accounting for the envi-

ronmentally sustainable potential When compared to the overallemissions of the energy sector in Brazil the bioelectricity potential

has a signi1047297cant potential to mitigate GHG emissions In fact in2010 the energy sector contributed to 399 million tonnes of GHG

Fig 6 Economic bioenergy potential in some municipalities of the Southeast region




emissions which was equivalent to nearly one third of the overallGHG emission in Brazil [88] In the future energy sector relatedGHG emissions tend to sharply rise as suggested by some recent

studies (see [108990]) Thus in mid- and long-term bioelectricitywill play an essential role to guarantee a secure and sustainablepower supply in Brazil

4 Final remarks

This study sought to quantify the technical sustainable andeconomically feasible potentials of agricultural and agro-industrial

residues to generate electricity via direct combustion in centralisedpower plants in Brazil Further the energy savings and GHGemission reduction potential of replacing natural gas-based elec-tricity by bioenergy have been assessed To this end an integrated

statistical a GIS-based analysis and a life cycle assessment havebeen conducted

Overall results reveal that the environmentally sustainable po-tential is nearly 141 TWhyear mainly concentrated in the South

Southeast and Midwest regions Residues of sugarcane soybeanand maize crops are the major feedstock for available bioenergy Onthe other hand the economic potential is far lower totalling some

39 TWhyear As for 2010 the evaluated biomass has no other ap-plications and is rather left on agricultural 1047297elds or treated inland1047297ll facilities However in the future other uses might becomecost-effective and possible competition might arise with the energysector This is particularly possible for bagasse leftovers in sugar-

cane distilleries which might have other valuable applications inchemical industries

This gap between the sustainable technical and economic po-tentials implies that constraints to bioenergy penetration for power

generation portfolios are not related to a lack of resources butrather owned to economic logistical regulatory and political bar-riers In fact agricultural residue resources are spread on thefarmland after harvesting activities with limited energy density per

km2 which increases collection costs Thus a mix of measures

could help boosting the use of residues in centralised power gen-eration systems in Brazil Firstly the coordination of small andmedium farmers into cooperatives or even the implementation of

energy service companies (ESCOs) for investing in power genera-tion facilities would lower transaction costs Secondly investmentcosts could be lowered through 1047297scal incentives Thirdly connec-

tion costs could be reduced through the de1047297nition of obligationsand control of market barriers from power utilities Finally regionaland exclusive auctions for residues power generation plants couldbe implemented by the Brazilian government in accordance to

what has been done forother alternative energy sources in Brazil inthe last decade Thus a 1047297scal incentive in the form of a Feed-in-Tariff (FIT) would encourage farmers to diversify their activitiesand include bioenergy in their business portfolio Another alter-

native to1047297

nance the implementation of centralised biomass power

plants could be through public-private partnerships to supportenvironmental projects as bioelectricity can result in signi1047297cantGHG emission reductions from replacing natural gas-based elec-

tricity The total GHG mitigation is nearly 18 million tonne CO 2eyear and could reach 64 million tonne CO2e yearly when thetechnical sustainable potential is considered

Furthermore supporting policies to foster centralised genera-

tion under a cooperative scheme would result in gains of economyof scale and improve the reliability of the feedstock supply Also

state governments should reconsider the power distributionnetwork as several municipalities with high bioenergy technical

potential do not have a neighbouring substation unit whichmakes non-viable the implementation of a centralised biomasspower plant

Despite the efforts to conduct an accurate analysis of bioenergy

potential in Brazil this study presents limitations that should berevised in future works to enhance the robustness of the 1047297ndings

i Residueproduct ratio and residue removal ratio are site-speci1047297c and should be adjusted to Brazilian farming charac-teristics rather than assumed based on theoretical values

ii The availability of agricultural residues for bioenergy po-

tential should be further investigated on the 1047297eld as someleftovers may be already used in other economic activitieswhich are not of 1047297cially reported

iii The combustion of residues is assumed to take place in a

common boiler but physical characteristics of residues mightinterfere with boiler ef 1047297ciencies

iv The density of residues was uniformly considered in eachmunicipality but in reality residues are heterogeneously

concentrated Thus further land use analyses should beconducted to speci1047297cally characterise the potential of eachmunicipality

v The economic distance to collect residues was considered to

be 50 km Nonetheless this distance may be constrained byseveral logistic and infrastructure limitations which shouldalso be better examined and

vi This study is focused on centralised power options This

affected the choice of the power generation technology andthe logistic restriction related to biomass collection Furtherstudies could assess Brazils waste-to-electricity potentialthrough different technological options such as gasi1047297cation

and organic Rankine cycles (ORC) In the latter case it wouldallow studying micro and small scale generators possibilitieswhich would be mostly installed as distributed generators

Acknowledgement

Thanks are due to the Brazilian National Research Council(CNPq) (4011642012-8 - APQ) for 1047297nancial support and to Raul

Miranda for his helpful comments about GIS processing data

Table 5

GHG emissions of the bioenergy system and avoided impacts

Bioelectricity system (environmentallysustainable potential) (mil tCO2e yr1)

Bioelectricity system (economicpotential) (mil tCO2e yr1)

Avoided impacts (environmentallysustainable potential) (mil tCO2e yr1)

Avoided impacts (economicpotential) (mil tCO2e yr1)

Upstream

processes

001 000 021 006

Downstream

processes

562 155 6342 1752

Total (cradle-to-grave)

563 156 6363 1758




Annex A

References

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[2] JLDS Soito M a V Freitas Amazon and the expansion of hydropower inBrazil vulnerability impacts and possibilities for adaptation to global climatechange Renew Sustain Energy Rev 15 (6) (2011) 3165e3177

[3] E Von Sperling Hydropower in Brazil overview of positive and negativeenvironmental aspects Energy Procedia 18 (2012) 110e118

[4] EPE National energy plan 2030 (Plano Nacional de Energia 2030) (in Portu-guese) 2007 Rio de Janeiro

[5] EPE Ten-year plan of energy expansion 2022( Plano decenal de expans ~ao deenergia 2022) (in Portuguese) 2013 Rio de Janeiro

[6] ONS Stored power operation data (Historico de operaccedil~ao energia armaze-nada) (in Portuguese) Operador Nacional do Sistema Eletrico 2014 (Online)available httpwwwonsorgbrhistoricoenergia_armazenadaaspx(accessed 090415)

[7] AFP de Lucena AS Szklo R Schaeffer RR de Souza BSMC Borba IVL daCosta AOP Juacutenior SHF da Cunha The vulnerability of renewable energy toclimate change in Brazil Energy Policy 37 (3) (2009) 879e889

[8] R Schaeffer AS Szklo AF Pereira de Lucena BS Moreira Cesar BorbaLP Pupo Nogueira FP Fleming A Troccoli M Harrison MS Boulahya En-ergy sector vulnerability to climate change a review Energy 38 (1) (2012)1e12

[9] IEA Brazil Energy Outlook 2013 Paris[10] LPP Nogueira A Frossard Pereira de Lucena R Rathmann P Rua Rodriguez

Rochedo A Szklo R Schaeffer Will thermal power plants with CCS play a rolein Brazils future electric power generation Int J Greenh Gas Control 24(May 2014) 115e123

[11] J Goldemberg R Schaeffer A Szklo R Lucchesi Oil and natural gas prospectsin South America can the petroleum industry pave the way for renewables inBrazil Energy Policy 64 (2014) 58e70

[12] J Domac K Richards S Risovic Socio-economic drivers in implementingbioenergy projects Biomass Bioenergy 28 (2) (2005) 97e106

[13] JM Joelsson L Gustavsson Reduction of CO2 emission and oil dependencywith biomass-based polygeneration Biomass Bioenergy 34 (7) (2010)967e984

[14] U a Schneider B a Mccarl Economic potential of biomass-based fuels forgreenhouse gas emission mitigation in Work Pap 01-wp 280 No August2001 pp 291e312

[15] RD Sands H Feuroorster C a Jones K Schumacher Bio-electricity and land usein the future agricultural resources model (FARM) Clim Change 123 (3e4)(2014) 719e730

[16] S Njakou Djomo O El Kasmioui T De Groote LS Broeckx MS VerlindenG Berhongaray R Fichot D Zona SY Dillen JS King I a JanssensR Ceulemans Energy and climate bene1047297ts of bioelectricity from low-inputshort rotation woody crops on agricultural land over a two-year rotationAppl Energy 111 (2013) 862e870

[17] M Junginger T Bolkesjoslash D Bradley P Dolzan A Faaij J Heinimeuroo B HektorOslash Leistad E Ling M Perry E Piacente F Rosillo-Calle Y RyckmansPP Schouwenberg B Solberg E Troslashmborg ADS Walter M De Wit De-velopments in international bioenergy trade Biomass Bioenergy 32 (8) (2008)717e729

[18] L Wright Worldwide commercial development of bioenergy with a focus onenergy crop-based projects Biomass Bioenergy 30 (8e9) (2006) 706e714

[19] BS Hoffmann A Szklo R Schaeffer An evaluation of the techno-economicpotential of co-1047297ring coal with woody biomass in thermal power plants inthe south of Brazil Biomass Bioenergy 45 (2012) 295e302

[20] K Hofsetz MA Silva Brazilian sugarcane bagasse energy and non-energy

Fig A Economic bioenergy potential per region in Brazil




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of availability of agriculture residues and wastes for integrated biore1047297neries inBrazil Resour Conserv Recycl 77 (2013) 78e88

[23] P Anselmo Filho O Badr Biomass resources for energy in North-EasternBrazil Appl Energy 77 (1) (2004) 51e67

[24] JL De Oliveira JN Da Silva E Graciosa Pereira D Oliveira Filho D RizzoCarvalho Characterization and mapping of waste from coffee and eucalyptus

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[25] MDFDS Ribeiro AP Raiher Potentialities of energy generation from wasteand feedstock produced by the agricultural sector in Brazil the case of theState of Parana Energy Policy 60 (2013) 208e216

[26] GM Fae Gomes ACF Vilela LD Zen E Osorio Aspects for a cleaner pro-duction approach for coal and biomass use as a decentralized energy source insouthern Brazil J Clean Prod 47 (2013) 85e95

[27] A Angelis-Dimakis M Biberacher J Dominguez G Fiorese S GadochaE Gnansounou G Guariso A Kartalidis L Panichelli I Pinedo M RobbaMethods and tools to evaluate the availability of renewable energy sourcesRenew Sustain Energy Rev 15 (2) (2011) 1182e1200

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[29] LF Pellegrini S de Oliveira Junior Combined production of sugar ethanoland electricity thermoeconomic and environmental analysis and optimiza-tion Energy 36 (6) (2011) 3704e3715

[30] JA Scaramucci C Perin P Pulino OFJG Bordoni MP da CunhaLAB Cortez Energy from sugarcane bagasse under electricity rationing inBrazil a computable general equilibrium model Energy Policy 34 (9) (Jun2006) 986e992

[31] EF Grisi JM Yusta R Dufo-L opez Opportunity costs for bioelectricity salesin Brazilian sucro-energetic industries Appl Energy 92 (2012) 860e867

[32] A Demirbas Combustion properties and calculation higher heating values of diesel fuels Pet Sci Technol 16 (7e8) (1998) 785e795

[33] S a Channiwala PP Parikh A uni1047297ed correlation for estimating HHV of solidliquid and gaseous fuels Fuel 81 (8) (2002) 1051e1063

[34] L Wilson W Yang W Blasiak GR John CF Mhilu Thermal characterizationof tropical biomass feedstocks Energy Convers Manag 52 (1) (2011)191e198

[35] LA Cortez EES Lora Biomass for energy [Biomassa para energia] [in Por-tuguese] UNICAMP Campinas SP Brazil 2008

[36] MY Koh T I Mohd Ghazi A review of biodiesel production from Jatrophacurcas L oil Renew Sustain Energy Rev 15 (5) (Jun 2011) 2240e2251

[37] ECN Phyllis 2 Database for Biomass and Waste 2012 (Online) availablehttpwwwecnnlphyllis2BrowseStandardECN-Phyllis (accessed051013)

[38] S Kim BE Dale Global potential bioethanol production from wasted cropsand crop residues Biomass Bioenergy 26 (4) (2004) 361e375[39] S Murali R Shrivastava M Saxena Quanti1047297cation of agricultural residues for

energy generation e a case study J EPHE 3 (2007) 27e31[40] J E a Seabra L Tao HL Chum IC Macedo A techno-economic evaluation of

the effects of centralized cellulosic ethanol and co-products re1047297nery optionswith sugarcane mill clustering Biomass Bioenergy 34 (8) (Aug 2010)1065e1078

[41] JEA Seabra IC Macedo Comparative analysis for power generation andethanol production from sugarcane residual biomass in Brazil Energy Policy39 (1) (2011) 421e428

[42] PS Murthy M Madhava Naidu Sustainable management of coffee industryby-products and value addition e a review Resour Conserv Recycl 66 (2012)45e58

[43] H Unal K Alibas Agricultural residues as biomass energy Energy SourcesPart B Econ Plan Policy 2 (2) (2007) 123e140

[44] B Gadde S Bonnet C Menke S Garivait Air pollutant emissions from ricestraw open 1047297eld burning in India Thailand and the Philippines EnvironPollut 157 (5) (2009) 1554e1558

[45] OECD Biomass and Agriculture Sustainability Markets and Policies 2004Paris

[46] MA Hassan LN Yee PL Yee H Arif 1047297n AR Raha Y Shirai K SudeshSustainable production of polyhydroxyalkanoates from renewable oil-palmbiomass Biomass Bioenergy 50 (2013) 1e9

[47] RP Singh a Embrandiri MH Ibrahim N Esa Management of biomass res-idues generated from palm oil mill vermicomposting a sustainable optionResour Conserv Recycl 55 (4) (2011) 423e434

[48] S Prasertsan P Prasertsan Biomass residues from palm oil mills in Thailandan overview on quantity and potential usage Biomass Bioenergy 11 (5) (1996)387e395

[49] W Pei Q Ng H Loong F Yuen M Kamal J Heng E Lim Waste-to-wealthgreen potential from palm biomass in Malaysia J Clean Prod 34 (September2011) (2012) 57e65

[50] INPE ldquoMonotoring of Sugarcane [Monitoramento da Cana-de-accediluacutecar] [inPortuguese]rdquo (Online) available httpwwwdsrinpebrlafcanasat

[51] JMCDS Dias DT De Souza M Braga MM Onoyama CHB MirandaPFD Barbosa JD Rocha Produccedil~ao de briquetes e peletes a partir de resiacuteduosagriacutecolas agroindustrais e 1047298orestais 2012 p 132

[52] EMBRAPA CNPTIA ldquoProduction Systems [Sistemas de produccedil~ao] [in Portu-guese]rdquo (Online) available httpsistemasdeproducaocnptiaembrapabr(accessed 270514)

[53] D Pimentel N Kounang Ecology of soil erosion in ecosystems Ecosystems 1(5) (1998) 416e426

[54] M a Altieri The ecological role of biodiversity in agroecosystems AgricEcosyst Environ 74 (1e3) (1999) 19e31

[55] JP Wight FM Hons JO Storlien TL Provin H Shahandeh RP WiedenfeldManagement effects on bioenergy sorghum growth yield and nutrient up-take Biomass Bioenergy 46 (2012) 593e604

[56] ECOFYS Global Potential of Renewable Energy Sources a Literature Assess-ment - Background Report 2008

[57] SWERANREL ldquoRenewable Energy Technical Potentials a GIS-Based Analysise Technical Reportrdquo (Colorado USA)

[58] IBGE Informaccedil~ao Estatiacutestica por Estado no Brasil 2010 Rio de Janeiro[59] NS Bentsen C Felby BJ Thorsen ldquoAgricultural residue production and po-

tentials for energy and materials services Prog Energy Combust Sci 40 (1)(2014) 59e73

[60] R Lal World crop residues production and implications of its use as a biofuelEnviron Int 31 (4) (2005) 575e584

[61] TLT Nguyen JE Hermansen L Mogensen Environmental performance of crop residues as an energy source for electricity production the case of wheatstraw in Denmark Appl Energy 104 (2013) 633e641

[62] N Scarlat M Martinov JF Dallemand Assessment of the availability of agricultural crop residues in the European Union potential and limitations forbioenergy use Waste Manag 30 (10) (2010) 1889e1897

[63] J Gan CT Smith Co-bene1047297ts of utilizing logging residues for bioenergyproduction the case for East Texas USA Biomass Bioenergy 31 (9) (2007)623e630

[64] MOS Dias MP Cunha CDF Jesus GJM Rocha JGC Pradella CEV RossellRM Filho A Bonomi Second generation ethanol in Brazil can it competewith electricity production Bioresour Technol 102 (19) (Oct 2011)8964e8971

[65] BS Hoffmann A Szklo R Schaeffer Limits to co-combustion of coal andeucalyptus due to water availability in the state of Rio Grande do Sul BrazilEnergy Convers Manag 87 (2014) 1239e1247

[66] A Burgi Avaliaccedil~ao do potencial tecnico de geraccedil~ao eletrica termossolar noBrasil a partir de modelagem em SIG e simulaccedil~ao de plantas virtuais Dis-sertaccedil~ao de Mestrado Universidade Federal do Rio de Janeiro Rio de Janeiro2013

[67] TP Fluri The potential of concentrating solar power in South Africa EnergyPolicy 37 (12) (2009) 5075e5080

[68] ANEEL Energy IGS data (Informaccedil~oes gerenciais de energia) (in Portuguese)2012

[69] I O for S ISO ISO - 14040e44 2006-Environmental management e life cycleassessment Environ Manag 3 (2006)

[70] AM Tillman Signi1047297cance of decision-making for LCA methodology Environ

Impact Assess Rev 20 (1) (2000) 113e

123[71] T Ekvall Cleaner production tools LCA and beyond J Clean Prod 10 (5)(2002) 403e406

[72] T Ekvall BP Weidema System boundaries and input data in consequentiallife cycle inventory analysis Int J Life Cycle Assess 9 (3) (2004) 161e171

[73] A Zamagni J Guinee R Heijungs P Masoni A Raggi Lights and shadows inconsequential LCA Int J Life Cycle Assess 17 (7) (2012) 904e918

[74] H Lund BV Mathiesen P Christensen JH Schmidt Energy system analysisof marginal electricity supply in consequential LCA Int J Life Cycle Assess 15(3) (2010) 260e271

[75] JH Schmidt System delimitation in agricultural consequential LCA outline of methodology and illustrative case study of wheat in Denmark Int J Life CycleAssess 13 (4) (2008) 350e364

[76] M Goedkoop M Oele M Vieira J Leijting T Ponsioen E Meijer SimaProTutorial Colophon 2014

[77] HS Eggleston L Buendia K Miwa T Ngara K Tanab K Hayama 2006Guidelines for National Greenhouse Gas Inventories Prepared by the NationalGreenhouse Gas Inventories Programme 2006 Kanagawa Japan

[78] Pre Consultants Ecoinvent Database 2013 (Online) available httpwww

ecoinventorgdatabase [79] G Myhre D Shindell F-M Breon W Collins J Fuglestvedt J Huang D Koch

J-F Lamarque D Lee B Mendoza T Nakajima a Robock G StephensT Takemura H Zhan 2013 Anthropogenic and natural radiative forcing inClim Chang 2013 Phys Sci Basis Contrib Work Gr I to Fifth Assess RepIntergov Panel Clim Chang 2013 pp 659e740

[80] Soren Using biogas for CHP andor transportation purposes in the long runin Danish Energy Agency Conference in ldquoDigestate and Biogas Utilizationepractices and Perspectives 2010

[81] M Junginger E de Visser K Hjort-Gregersen J Koornneef R Raven A FaaijW Turkenburg Technological learning in bioenergy systems Energy Policy 34(18) (2006) 4024e4041

[82] RFC Miranda A Szklo R Schaeffer Technical-economic potential of PV systems on Brazilian rooftops Renew Energy 75 (December 2012) (2015)694e713

[83] I Obernberger Decentralized biomass combustion state of the art and futuredevelopment11Paper to the keynote lecture of the session ldquoProcesses fordecentralized heat and power production based on cumbustionrdquo at the 9thEuropean Bioenergy Conference June 1996 Copen Biomass Bioenergy 14 (1)




(1998) 33e56[84] H Liu Y Shao J Li A biomass-1047297red micro-scale CHP system with organic

Rankine cycle (ORC) - thermodynamic modelling studies Biomass Bioenergy35 (9) (2011) 3985e3994

[85] BF Tchanche M Petrissans G Papadakis Heat resources and organic Rankinecycle machines Renew Sustain Energy Rev 39 (2014) 1185e1199

[86] M Imran BS Park HJ Kim DH Lee M Usman M Heo Thermo-economicoptimization of regenerative organic Rankine cycle for waste heat recoveryapplications Energy Convers Manag 87 (2014) 107e118

[87] S Lecompte H Huisseune M van den Broek B Vanslambrouck M De Paepe

Review of organic Rankine cycle (ORC) architectures for waste heat recovery

Renew Sustain Energy Rev 47 (2015) 448e461[88] MCTI Annual inventory of greenhouse emissions in Brazil (in portuguese)

(lsquoEstimativas anuais de emiss~oes de gases de efeito estufa no Brasi) 2013Brasiacutelia

[89] AFP Lucena L Clarke R Schaeffer A Szklo PRR Rochedo K DaenzerA Gurgel A Kitous T Kober Climate Policy Scenarios in Brazil a multi-model comparison for energy Clim Policy (2015) 1e25

[90] J Portugal-Pereira A Koberle A Lucena A Szklo R Schaeffer Overlookedimpacts of power generation the life cycle side of the story in 2nd Inter-national Conference on Energy and Environment Bringing Together Engi-

neering and Economics 2015




dispatch of thermal power plants has been decreasing sharply tohistorically low levels While in late 1990s the water available incountrys reservoirs had capacity to supply 1047297rm power equivalentto consumption needs for about four months as of beginning of

2015 waterin reservoirs only guaranteed supply up to one month of demand

Forecasts predict that electricity consumption will double from2010 levels to 1100 TWh in 2035 [9] Following a business-as-usual

scenario this growth will partly be met with fossil fuel resources

[10] In recent years the Brazilian government has announcedaggressive investments to explore pre-salt oil and gas reserves and

even unconventional natural gas (shale and tight) This is seen as astrategy to increase the energy security of supply and to foster theresilience and resource diversi1047297cation of the power supply sector inparticular [11] Paradoxically in global terms increasing the share

of fossil fuels in the electricity generation portfolio results in higherGHG emissions with the possible consequence of inducing moresevere weather events which indirectly intensi1047297es the vulnera-bility of hydropower systems Thus the country is currently trap-

ped in a development vicious cycleRecent attention has been put on bioelectricity as a feasible

alternative to turn this tendency into a virtuous cycle It wouldsimultaneously diversify energy sources [12] reduce fossil-fuel

dependence [1314] and tackle climate change [1516] Althoughtraditional dedicated biomass has already a signi1047297cant expressionin the countrys power supply particularly based on sugarcanebagasse thermal power plants [17e20] there is a vast potential

from agricultural and agro-industrial residues which are currentlynot recovered Instead of being left on the farmland and slowlydecomposed (aerobically on the1047297eld or anaerobically in land1047297lls orcommon garbage dumps) releasing GHG emissions this valuable

feedstock could be collected and processed to generate electricityvia conventional thermochemical processes Assessing the bio-energy potential is therefore essential to characterise feedstocksboth qualitatively and quantitatively and to prospect the potential

substitution of fossil fuels and the associated reduction in GHGemissions

A small number of studies can be found in the literature thattouches this subject At the national level the technical potentialfor electricity generation from major agricultural crop residues andanimal manure has been estimated [2122] In more detail other

assessments quanti1047297ed the energy potentials of the main biomassresources in different regions of Brazil [23e26] A common limi-tation of these studies is the reliance on crude assumptions andsimple national statistics to quantify the potential of residue pro-

duction disregarding the economic and environmental limitations

of residue collection and processing Furthermore previous studiesare restricted to a speci1047297c area in the country or to a particular

technology Another downside is the lack of georeferenced statis-tical data in the bioenergy potential estimations As highlighted by[27] data about spatial distribution of biomass are needed tooptimise the ef 1047297cient use of resources

Aiming at overcoming this gap this study attempts to estimatethe technical environmentally sustainable and economic feasiblepotentials of agricultural and agro-industrial residues to generateelectricity via direct combustion in centralised systems in Brazil

Further it applies an integrated geographic information system(GIS)-based analysis to map residue availability and assesses howmuch bioenergy can replace fossil fuel resources and contribute to areduction in GHG emissions To this end a statistical analysis has

been conducted followed by a GIS mapping which identi1047297esoptimal locations for bioenergy generation centres under techno-economic and environmental constraints Then a life-cycleapproach has been undertaken to quantify the non-renewable

energy and GHG emission savings from replacing fossil-fuel-based electricity

This paper is structured as follows Section 2 presents the in-tegrated assessment applied in the study including key theoretical

principles about analytical quanti1047297cation of bioenergy with a sta-tistical based approach and GIS mapping as well as assumptionsapplied in the environmental assessment This is followed by Sec-tion 3 which discusses key results lessons learnt and limitation of

the study Lastly Section 4 outlines 1047297nal remarks and implicationsof the study to policy making

Fig 1 Regulation capacity of hydropower reservoirs in Brazil

Source Own elaboration based on [6]




























residues










dues as follows

RP j frac14X


where





RP k frac14X


where



















Table 1








Bagasse 1981 1039 022 10 50

Filter cake 1981 1039 002 10 50

Rice Straw 1722 863 154 100 50

Husk 1708 1000 026 30e

50Soybean Straw 2009 1400 201 100 40


Peanut Straw 2010 1400 252 100 33

Shell and husk 1898 799 056 70 33

Coffee Husk 1939 1075 059 50 58

Coconut Husk 2150 810 084 90 100

Shell 2009 1400 042 90 100

Palm oil Shell 1554 799 006 80 100

Fibres 1562 799 012 80 100

Empty fruit

bunches

1517 1200 020 100 100


Rye Straw 2008 820 161 100 25

Barley Straw 1968 881 148 100 25

Corn Stover 1867 565 153 100 50


Wheat Straw 1954 1124 155 100 33

























231 Goal and scope














232 Functional unit





Table 2








power plants
































thorn to NO3




























Table 3


Parameters

Upstream




Life time 30 years



1



Life time 10 years


Downstream



Life time 15 years


Table 4




Upsteam




Downstream




Reference systems













































4 Final remarks















native to1047297






















Acknowledgement



Table 5






Upstream

processes

001 000 021 006

Downstream

processes

562 155 6342 1752


563 156 6363 1758




Annex A

References





































































































































residues










dues as follows

RP j frac14X


where





RP k frac14X


where



















Table 1








Bagasse 1981 1039 022 10 50

Filter cake 1981 1039 002 10 50

Rice Straw 1722 863 154 100 50

Husk 1708 1000 026 30e

50Soybean Straw 2009 1400 201 100 40


Peanut Straw 2010 1400 252 100 33

Shell and husk 1898 799 056 70 33

Coffee Husk 1939 1075 059 50 58

Coconut Husk 2150 810 084 90 100

Shell 2009 1400 042 90 100

Palm oil Shell 1554 799 006 80 100

Fibres 1562 799 012 80 100

Empty fruit

bunches

1517 1200 020 100 100


Rye Straw 2008 820 161 100 25

Barley Straw 1968 881 148 100 25

Corn Stover 1867 565 153 100 50


Wheat Straw 1954 1124 155 100 33

























231 Goal and scope














232 Functional unit





Table 2








power plants
































thorn to NO3




























Table 3


Parameters

Upstream




Life time 30 years



1



Life time 10 years


Downstream



Life time 15 years


Table 4




Upsteam




Downstream




Reference systems













































4 Final remarks















native to1047297






















Acknowledgement



Table 5






Upstream

processes

001 000 021 006

Downstream

processes

562 155 6342 1752


563 156 6363 1758




Annex A

References





















































































































Table 1








Bagasse 1981 1039 022 10 50

Filter cake 1981 1039 002 10 50

Rice Straw 1722 863 154 100 50

Husk 1708 1000 026 30e

50Soybean Straw 2009 1400 201 100 40


Peanut Straw 2010 1400 252 100 33

Shell and husk 1898 799 056 70 33

Coffee Husk 1939 1075 059 50 58

Coconut Husk 2150 810 084 90 100

Shell 2009 1400 042 90 100

Palm oil Shell 1554 799 006 80 100

Fibres 1562 799 012 80 100

Empty fruit

bunches

1517 1200 020 100 100


Rye Straw 2008 820 161 100 25

Barley Straw 1968 881 148 100 25

Corn Stover 1867 565 153 100 50


Wheat Straw 1954 1124 155 100 33

























231 Goal and scope














232 Functional unit





Table 2








power plants
































thorn to NO3




























Table 3


Parameters

Upstream




Life time 30 years



1



Life time 10 years


Downstream



Life time 15 years


Table 4




Upsteam




Downstream




Reference systems













































4 Final remarks















native to1047297






















Acknowledgement



Table 5






Upstream

processes

001 000 021 006

Downstream

processes

562 155 6342 1752


563 156 6363 1758




Annex A

References






























































































































231 Goal and scope














232 Functional unit





Table 2








power plants
































thorn to NO3




























Table 3


Parameters

Upstream




Life time 30 years



1



Life time 10 years


Downstream



Life time 15 years


Table 4




Upsteam




Downstream




Reference systems













































4 Final remarks















native to1047297






















Acknowledgement



Table 5






Upstream

processes

001 000 021 006

Downstream

processes

562 155 6342 1752


563 156 6363 1758




Annex A

References









































































































































thorn to NO3




























Table 3


Parameters

Upstream




Life time 30 years



1



Life time 10 years


Downstream



Life time 15 years


Table 4




Upsteam




Downstream




Reference systems













































4 Final remarks















native to1047297






















Acknowledgement



Table 5






Upstream

processes

001 000 021 006

Downstream

processes

562 155 6342 1752


563 156 6363 1758




Annex A

References

































































































































Table 3


Parameters

Upstream




Life time 30 years



1



Life time 10 years


Downstream



Life time 15 years


Table 4




Upsteam




Downstream




Reference systems













































4 Final remarks















native to1047297






















Acknowledgement



Table 5






Upstream

processes

001 000 021 006

Downstream

processes

562 155 6342 1752


563 156 6363 1758




Annex A

References



















































































































































4 Final remarks















native to1047297






















Acknowledgement



Table 5






Upstream

processes

001 000 021 006

Downstream

processes

562 155 6342 1752


563 156 6363 1758




Annex A

References













































































































Annex A

References











































































































agricultural and agro-industrial residues-to-energy techno-economic and environmental assessment in...

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