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Energy 101 (2016) 91e99

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Energy

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Energy crop storage: An alternative to resolve the problem ofunpredictable hydropower generation in Brazil

Julian David Hunt*, 1, Vincent Guillot, Marcos Aur�elio Vasconcelos de Freitas,Renzo S.E. SolariInternational Virtual Institute of Global Change, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil

a r t i c l e i n f o

Article history:Received 18 August 2015Received in revised form28 December 2015Accepted 3 February 2016Available online xxx

Keywords:EucalyptusEnergy cropsEnergy storage

* Corresponding author. Centro de Tecnologia, blocRio de Janeiro, CEP 21949-972, Brazil. Tel.: þ55 21 98

E-mail addresses: julian.hunt@ivig.coppe.ufrj.br (gmail.com (V. Guillot), mfreitas@ivig.coppe.ufrj.brcoppe.ufrj.br (R.S.E. Solari).

1 Permanent address: Av. Prado Junior, 237, 901,Brazil.

http://dx.doi.org/10.1016/j.energy.2016.02.0110360-5442/© 2016 Elsevier Ltd. All rights reserved.

a b s t r a c t

Due to the lack of energy storage in the new hydropower plants in the Amazon region, Brazil will requirethermoelectric power plants to generate electricity during the dry period (MayeOctober). Biomass basedelectricity generation, especially eucalyptus trees, can be used to replace the expensive liquefied naturalgas infrastructure required to generate electricity during the dry seasons and emergency generationduring dry years in Brazil. This article presents a new electricity generation scheme called “Energy CropStorage”. In this scheme, biomass is grown and stored in eucalyptus plantations in order to match thesupply of energy to its demand. For example, during wet years in Brazil, when biomass plants operate at50% capacity, the eucalyptus trees are allowed to continue growing. During dry years, the biomass storedis used more intensively as biomass generation raises to 90% of its capacity. It was concluded that naturalgas is a high risk investment in Brazil because, if there are several consecutive wet years, the expensiveinfrastructure dedicated to natural gas based electricity generation will remain on standby. Biomassplantations, on the other hand, are a more reliable investment as the biomass is stored when the biomassdemand is lower.

© 2016 Elsevier Ltd. All rights reserved.

1. Introduction

The Brazilian Southeast is currently going through one of itsworst droughts [1]. This is starting to bring into question thecapability the country has to rely on its hydropower generation andenergy storage capacity. The published decennial electricity plan2013e2023 [2] expects that the Brazilian hydropower storage po-tential will generate electricity until the end of the dry period andthat, with additional support from natural gas backup generation,the annual demand for energy would be met. In addition, hydro-power storage would serve as a buffer to the wind and solarintermittent electricity generation. The Brazilian climate seems tobe changing over recent years, either due to global climatic changesor due to changes in regional climate resulting from deforestation,

o C, sala 211, Ilha do Fund~ao,923 2088.J.D. Hunt), vincentguillot11@(M.A.V. Freitas), renzo@ivig.

Copacabana, Rio de Janeiro,

the reliability of hydropower generation in Brazil is becomingquestionable [3].

Over the next 10 years, the hydroelectric energy storage capacitywill not increase as the new hydropower generation, which willincrease 33% in the next 10 years. This increase will be in theAmazon water basin with no storage and most of its electricity willbe generated during the wet period without storage [2]. Other al-ternatives such as wind and solar will partially complement theelectricity generation. The Brazilianwind potential has started to beexplored and is foreseen to reach 24 GW of wind power by 2024.This is convenient because it generates more electricity during thedry period, when hydropower generation is reduced. Solar powerhas less seasonal variations and is set to increase by 7 GW capacityby 2024.

Natural gas based electricity generation in Brazil has an esti-mated capital cost of US$ 1.07 million/MWand an operation cost ofUS$ 66/MWh2 [4] to cover the infrastructure to explore, extract,process and transport the gas to the power plant and to generateelectricity with the gas. This investment should cover the worst

2 Brazilian Reals to Dollar to conversion of 3.5.

J.D. Hunt et al. / Energy 101 (2016) 91e9992

scenario in order to guarantee that there will be enough electricitygeneration in case of a dry year in Brazil.

Considering the supply over the last few years, this infrastruc-ture was used at only around 28% of its capacity, see Fig. 1. This isnot an appropriate investment as the capacity is under-utilized. Inaddition, it increases the cost of natural gas in the market for theindustrial, residential and commercial sectors to guarantee thesupply of natural gas for electricity generation. The priority pro-gram for thermal power plants schemes was created especially tosubsidise natural gas for electricity generation and has beenextensively criticized [5].

Fig. 1 shows a trend of increased natural gas generation. This is aresult of lower than the average rainfall in 2012, 2013 and 2014,which resulted in an increase in electricity prices up to 70% in 2015.The consumption of natural gas is set to increase even furtherduring the dry period due to the lack of increase in Brazilian storagecapacity.

Biomass electricity generation based on eucalyptus plantationshas an estimated capital cost of US$ 1 million/MW and flexibleoperation cost of US$ 44/MWh to cover the costs of land use,seeding, harvesting, cutting, biomass transportation, gasifying orburning the biomass to generate electricity [7]. This article arguesthat an important aspect of biomass is its flexible operation cost,which makes it possible to generate energy when it is required. Forexample, if there are 4 wet years in a row, the investment in theeucalyptus plantations will be reduced after the second year andthe eucalyptus trees will continue growing, reducing the futureinvestment costs.

This article compares both natural gas and biomass sourcesof energy and proposes a solution to the unreliable Brazilianhydroelectric storage potential through the planting of large-scale eucalyptus plantations. This assures the generation ofelectricity when there is lower than average hydropowergeneration.

This paper is divided into sections. Section 1.1 describes theissues Brazil will have to face to generate electricity in the nextdecades and presents alternative solutions. Section 1.2 presentsthe environmental and social issues involved in the plantation ofeucalyptus. Section 1.3 indicates that the reduction in paperconsumption will facilitate the increase of eucalyptus basedelectricity generation. Section 2.1 presents the new schemecalled “ECS” (Energy Crop Storage). Section 2.2 shows that theECS scheme is suitable to the Brazilian energy sector and climate.Section 2.3 describes how ECS could be implemented in Brazil.Section 3 presents the results of the implementation of ECS inBrazil. Section 4 discusses the other aspects that influence thisresearch, and presents the advantages and disadvantages ofbiomass electricity. Section 6 presents the conclusion of thispaper.

Fig. 1. Maximum and actual electricity generation capacity from natural gas in Brazil.Data taken from Refs. [2,6].

1.1. Brazilian electricity generation for the next decades

Brazil generates around 70% of its electricity from hydropowerand still has an enormous hydroelectricity potential to be devel-oped in the Amazon Watershed. However, due to its flat geology,large storage reservoirs are not practical in the Amazon region [3].Thus, they will generate most of it electricity during 6 months inthe wet season (NovembereApril).

Current studies propose the further development of the Amazonhydro potential with the inclusion of Seasonal Pumped-StorageSchemes, named “Enhanced-Pumped-Storage”, in the Southeastregion, to store energy during the six wet months and generateelectricity during the six dry months [8]. The South, Southeast andNortheast regions of Brazil have the appropriate geology for theconstruction of storage reservoirs and can be used to store theenergy generated in the Amazon. Fig. 2 shows how this Enhanced-Pumped-Storage could be used to allow Brazil to develop all thehydropower potential in the Amazon region, by increasing thestorage capacity in the other regions.

The current Governmental solution is to generate thermoelec-tricity during the six dry months, especially with LNG (liquefiednatural gas) based Gas fired power plants. In addition, in case of anexceptionally dry year, as in 2013, 2014 and 2015, the power plantswould operate as base load throughout the year to replace the lackof hydropower.

The proposed solution in this article is similar to the currentGovernmental solution. However, instead of LNG based electricitygeneration, the thermoelectricity would be generated with euca-lyptus using the ECS scheme.

1.2. Myths and truths about eucalyptus in Brazil

Eucalyptus plantations in Brazil are increasing and the marketfor its products are promising. In 2013, Brazil already had 7.2million hectares of planted eucalyptus trees, out of 360 millionhectares of arable land, as shown in Fig. 3. With current policies andgovernment incentives, the country is set to double its plantedforest to 16 million hectares in 10 years [9].

Although some sectors of society believe that eucalyptus maycause negative effects on biodiversity, it can be seen as an alter-native for nature conservation because it reduces the impact onnative forests. Moreover, eucalyptus plantations show environ-mental benefits such as reduced erosion, increased infiltration ofrainwater, local climate conservation, biomass production, captureand storage of CO2, among others. Currently, there is no more spacein the market for productive segments that do not reconcile eco-nomic activity with environmental preservation. In this context,the growing eucalyptus is presented as a sustainable forest plan-tation, able to meet these new environmental assumptions [9].Table 1 presents the main products and services resulted fromeucalyptus plantations. Another benefit from biomass energy cropsis the high number of jobs created [10].

Fig. 4 shows the average productivity of eucalyptus plantationsin Brazil. It varies considerably with the climate, especially theaverage precipitation of the region. The average production ofplanted eucalyptus forests is 41 m3/ha/year, with a maximum po-tential of 70 m3/ha/year [11]. It is, therefore, essential to the searchfor increased productivity of these forests, both in nurseries and inthe field [12].

1.3. Decrease of paper production

Around 33% of forestry plantations in Brazil are used to producecellulose [14]. The production of cellulose in Brazil increased from 9billion tons in 2003 to 15 billion tons in 2013 [15].

Fig. 2. Proposed solution for energy storage using Enhanced-Pumped-Storage to complement the electricity generation in the Amazon during the wet period. Original backgroundfigure taken from Ref. [8].

J.D. Hunt et al. / Energy 101 (2016) 91e99 93

However, the world's paper industry is reaching its limits as thedemand is decreasing. People are sharing information over theinternet and using software for work, reducing the need for paper.This pattern is likely to become more common as young peoplebecome accustomed to reading on digital screens instead ofnewspapers, magazines and books. Thus, it is expected that theworld paper production will eventually fall.

Fig. 3. Agricultural land distribution in Brazil. Figure taken from Ref. [9].

For example, paper consumption in the US is already falling, butthis has being buffered by the growth in Chinese consumption, asseen in Fig. 5. It might reach a point when the BRICS consumptionwill start to fall similarly to the US and Europe. Thus, the Brazilianeucalyptus plantation sector will have to change its market focus.Electricity generation is a good alternative for paper makingproduction.

The differences between eucalyptus forests for cellulose andbiomass production are the eucalyptus species used, the biomasstrees are cut sooner and are planted with a smaller spacing, typi-cally 2 � 2 m, or more than 2.500 trees per hectare and energyforests are characterized by smaller diameter trees [17].

2. Methodology

This article explores the possibility of storing energy in euca-lyptus plantations in order to give more flexibility to biomassgeneration and help the supply of bioenergy tomeet the demand ofenergy. This methodology is applied with the intention to adapt theuse of biomass to the peculiarities of the Brazilian electricity gen-eration sector. Firstly, this section presents a new concept named“ECS” (Energy Crop Storage). Secondly, it shows how the probabilityof dry and wet years in Brazil suits the ECS eucalyptus based

Table 1Products and services resulted from eucalyptus plantations. Table taken from Ref. [9].

Product, service Final product, service description

Wood Fuel, charcoal, poles, railway sleepers, piling for foundations, reconstituted wood panels, pulp, construction, crates, joineryCellulose Paper, toilet paper, diapers, medicine capsules, thickeners for food, electronicsLeaves Essential oils (cleaning, hygiene, cosmetics) and ornamentationCO2 sequestration One hectare of eucalyptus removes 60 tons of CO2 from the atmosphereEnvironmental services Protection against soil erosionSocial services Sustainable income to families in rural municipalities

Fig. 4. Average productivity of eucalyptus plantations without irrigation. Figure taken from Ref. [13].

J.D. Hunt et al. / Energy 101 (2016) 91e9994

electricity generation. Thirdly, it is shown how eucalyptus basedECS schemes should be implemented in Brazil.

2.1. ECS (Energy crop storage)

Energy Crop Storage is a concept that provides long term storageto bioenergy. The alternative for ECS to use a storage facility for thecut wood. However, an additional long term storage facilityconsiderably increases biomass costs. The need for long termstorage happens in countries inwhich their electricity consumptionand/or generation varies considerably with changes in climate andin countries that want to increase energy security.

Due to its environmental flexibility, high productivity (morethan 60m3/ha/y have been reported [18]) and energy characteristics(wooddensity andheat capacity [19]), eucalyptus is themostwidelyused tree for energy generation. The tree genus has been acclaimedas one of the best options for energy production due mainly to thelarge number of species,which enableswide ecological distribution,favouring its introduction in various regions with different soil andclimatic conditions [20]. Two species (Eucalyptus uro-phylla� Eucalyptus Grandis), spacing (3m� 3m) and location (TresLagoas Municipality), are considered in this article [21].

The main concept behind the ECS scheme is to allow the euca-lyptus to grow when there is less need to generate

Fig. 5. Declining paper consumption in OECD countries. Figure taken from Ref. [16].

J.D. Hunt et al. / Energy 101 (2016) 91e99 95

thermoelectricity and consume the eucalyptus when there is ur-gency in generating electricity. For example, in a year with goodrainfall, during the dry period the biomass power plant wouldoperate at full load and during the wet period it would not operate,resulting in an overall 50% capacity factor. This would allow theeucalyptus to grow at a higher rate, storing extra biomass for futureuse. In a dry year, the plant would operate near full capacitythroughout the whole year, which could result in a capacity factorclose to 90%. This would then consume the biomass previouslystored in the form of eucalyptus trees. This scheme is explained inFig. 6.

2.2. Suitability of ECS with the Paran�a Watershed region in Brazil

In order to check if the Energy Crops Storage scheme presentedin this paper is suitable for Brazil's climate it is important to analysethe probability of consecutive dry years and consecutive wet years.The schemewould not produce good results if there is a periodwithmore than four consecutive dry years.

The methodology was used to estimate the occurrence of dryand wet years is based on the flowrate of the Itaipú Dam to indicate

Fig. 6. Energy Crop Storage scheme suited to a

if a year was dry or wet. This flowrate represents an estimate of therainfall in the Paran�a Water Basin, apart from the Iguaçu River andParaguay River. Other reasons for choosing the Paran�a water basinare because it covers a huge arable land in Brazil and it has veryhigh potential for eucalyptus productivity, see Fig. 4. .

The median annual flowrate at the Itaipú Dam between 1972and 2012 is equal to 11,554 m3/s. It is assumed that a flowrate 5%smaller, i.e. 10,976 m3/s, is considered a dry year and a flowrate 5%bigger, i.e. 12,131 m3/s, is considered a wet year, as shown in Fig. 7.Fig. 8 shows the probability of consecutive dry and wet years. It canbe concluded that for this basin more than 4 consecutive dry or wetyears have not been seen over the measurement period.

Fig. 9 shows the difference between the median annual flowrateat the Itaipú Dam between 1972 and 2012 and the annual flowrateat the Itaipú Dam (the zero in the graph is equal to the median). Itshows that there is an appropriate balance between wet and dryyears. In other words, after dry years, there are a similar number ofwet years and after wet years there are a similar number of dryyears. This is convenient for the ECS scheme because after a few dryyears, when the average age of the trees in the eucalyptus planta-tions decrease, will follow wet years where there will be less need

ccommodate the Brazilian Energy Sector.

Fig. 7. Monotonic curve of annual average flowrate at the Itaipú Dam, from 1972 to 2012.

Fig. 8. Probability of consecutive dry or wet years in the Paran�a Water Basin.

Fig. 9. Change in average annual flowrate at the Itaipú Dam compared with the median of the flowrate between 1972 and 2012.

J.D. Hunt et al. / Energy 101 (2016) 91e9996

for thermoelectricity generation and the plantation can keepgrowing, thus the average age of the eucalyptus plantationsincreases.

2.3. ECS in Brazil

The original scheme for eucalyptus energy crops in Brazilbased on eucalyptus plantations that maintain the same plantingdensity throughout the production cycle, and whose interest forproduction is the tonnage of wood per hectare, the age of cutting

is achieved when the value of Dry Mass Annual Growth, i.e. thevalue of the annual increment, equals to the value of the DryMass Average Annual Growth, i.e. the average growth across yearzero and the year under analysis, as shown in Fig. 10. At this age,the eucalyptus plantation reaches the maximum value of woodproduction per unit area per year [21], which corresponds to thefifth year in Fig. 10. Usually this is the year when the trees arecut. Fig. 11 presents the cash flow for an eucalyptus plantionwhich was cut after 8 years. The costs assumed were taken fromTable 2.

Fig. 10. Dry mass annual and average annual volume growth per hectare of eucalyptus plantations [21].

Fig. 11. Annual and average annual cash flow per hectare of eucalyptus plantations [21].

J.D. Hunt et al. / Energy 101 (2016) 91e99 97

This article proposes a new scheme to cut the eucalyptus withthe intent to increase the energy storage capacity. In this way, theusual amount of time that the biomass is left to grow will changefrom 5 years to a range between 4 and 8 years, as shown in Fig. 10.During wet years, as the need to generate thermoelectricity be-comes less, the plantation average age increases, reaching amaximum age of 8 years. During dry years, as there is urgency ingenerating electricity, the plantation average age is reduced, downto a minimum age of 4 years old.

In case of a series of dry years, when there is the need operatethe electricity generation system at full capacity (close to 90% of thecapacity factor) as explained in Section 2.1, the older trees will becut first. However, when the trees reach a minimum of 4 years, thepower plant will have to operate at 50% capacity. This is becausethere will be no more biomass stored as eucalyptus trees tomaintain 90% generation capacity.

The difference in the ratio between the operation during dryyears (90%) and the operation duringwet years (50%), is equal to 1.8.This means that during a dry year there will be 80% more biomasselectricity generation. This is similar to the ratio between the age ofthe trees before cutting in wet years (8) and the age before cuttingin dry years (4), equal to 2. This means that the system could be ableto operate with 90% capacity for more than 4 dry years.

Such a scheme would not only allow Brazil to have a pro-grammed scheme for yearly variations in thermoelectricity gener-ation but it could also work as a buffer to give the country time tocreate other measurements to resolve the lack of electricitygeneration.

The cost estimates for eucalyptus plantation was taken fromWilchen et al. 2008 [22] and were adapted to 2015 using an infla-tion rate of 6%. The cost per hectare of fertile land for eucalyptusplantation is estimated to be US$ 428 per hectare. Table 2 shows thecosts of eucalyptus plantations in Brazil. Note that the cost analysisonly assumes one production cycle. However, each eucalyptus treecan be cut two or three times before having to be replaced. This canfurther reduce the final electricity cost.

3. Results

3.1. ECS costs in Brazil

Assuming an initial investment of US$ 1,665/ha, and that a drytonnage of eucalyptus is sold for US$ 29, the owner of the planta-tion will have an average return on his investment of 21.5% (Fig. 11)including an interest rate of 6% and land rental of US$ 429/ha. Thisis a reasonable return for the investment and US$ 29 per dry tonne

Table 2Eucalyptus plantation costs in Brazil.

Year Activities Labour costs US$/ha Total costs US$/ha Cumulative costs

0 Plantation preparation 209 293 293Plantation 148 442 735Maintenance & land 273 929 1665

1 Maintenance & land 27 491 21552 Maintenance & land 28 520 26753 Maintenance & land 30 551 32264 Maintenance & land 32 584 38105 Maintenance & land 33 619 44296 Maintenance & land 35 656 50867 Maintenance & land 38 696 57828 Maintenance & land 40 369 6150

Cutting 159 397 6547

J.D. Hunt et al. / Energy 101 (2016) 91e9998

of wood will result in a fuel cost of 18 US$/MWhe in the powerplant assuming a LHV of 5.4 MWh/t and an electricity generationefficiency of 30%.

In a dry year the eucalyptus is sold after 4 years growth, theowner of the plantationwill make a 27.2% return in the investment,which is better than cutting in 8 years. This is convenient to thethermoelectric power plant operator because the farmers will wantto cut the trees after 4 years but the thermoelectric generationdemand will dictate when to cut the wood. The plantation ownerswill have the return on their investment guaranteed if they cutbetween 4 or 8 years.

3.2. Increasing the Brazilian energy storage potential

The hydropower plants to be built on the Amazon Rivergenerate most their electricity from December to May and have40 GW foreseen [23]. Assuming that this power will reduce by 70%during the dry period, there will be the need for 28 GW of ther-moelectric generation from May to November.

Assuming that a capacity to generate 30 GW through eucalyptusECS thermoelectric generation to complement the excess genera-tion during the dry period in the Amazon, and that the eucalyptusplantation age reaches 8 years, it is estimated that there will bearound 105 TWh of biomass stored to operate the 30 GW capacityat 90% capacity for around 4 years. This is equivalent to 49.5% of theBrazilian energy storage capacity. In one year, this schemewould beable to consume 26 TWh of biomass energy stored. This is equiv-alent to the hydroelectric energy stored in the Furnas reservoir, thesecond biggest energy storage reservoir in the Brazil.

The estimated eucalyptus plantation land required to providethe above energy services is 5.3 million hectares. This is equivalentto 73.5% of the already existing eucalyptus plantations in Brazil and,with the future reduction in paper production, this could facilitatethe dissemination of eucalyptus destined for electricity generation.

4. Discussion

There are several details of the ECS scheme. This section at-tempts to explain the more important ones.

Table 3Typical scale of operation for various sizes and types of bioenergy plants. Table taken fro

Electricity generation (MW) Plant type Biomass (oven dry tonnes

0.01e0.025 (5500 h) Gasification 40e600.05e0.15 (5500 h) Gasification 100e12000.35e1.50 (5500 h) Gasification 1000e50005e10.0 (5500 h) Gasification 30,000e60,00025e40 (4400 h) Incineration 90,000e150,000

When there aremore than 4 consecutivewet years, the height ofthe plantations will stabilise at a maximum of 8 years growth. Thisis because the cumulative growth rate in tonnes/ha of eucalyptusplants with 4e8 years is around the half of the cumulative growthof plants with 0e4 years (Fig. 10). Thus, after a series of wet yearsthe maximum age of the plantation reaches an equilibrium of 8years, generating electricity with 50% capacity. This will allow thebiomass to be stored in case of a series of dry years. Another reasonwhy this scheme is convenient is becausewhen there are a series ofwet years, there will be water available to keep a high growth foreucalyptus trees with 8 years. The higher the eucalyptus plantation,the more water it will require to keep a high growth rate.

On the other hand, during more than 4 consecutive dry years,the average height of the plantations will be reduced, reaching theminimum cutting age of 4 years. Up to the point when the treesreach this age, the biomass thermoelectric power plants will beoperating at full capacity. If the dry years continue, then thebiomass power plants will have to stop operating with 90% capacityfactor and will have to operate at 50% capacity factor and theeucalyptus trees will continue to be cut at 4 years old.

Table 3 shows the type of plants that should be used for differentsizes and the amount of lorries and land area required [24]. Undernormal circumstances the scheme operates for 4400 h during thedry period as base load with incineration and 1100 h during thewetperiod with gasification and syngas storage. Other biomass basedelectricity generation technologies can be seen in Ref. [24].

It should be noted, however, that the plantations areas will onlybe able to generate electricity for around 4 consecutive dry years. Itis not advisable to rely only in biomass because after 4 consecutivedry years there will not be enough eucalyptus to generate elec-tricity with 90% capacity factor. In addition, land productivity de-creases during dry conditions, which will further decrease theavailability of biomass after an extended dry period.

Eucalyptus plantations consume a lot of water. Energy demandand costs for irrigation is high [26]. However, as most of thewood isplanned to be cut during the dry period and during a dry year, theECS scheme is convenient because:

1) During the dry period, the water consumption of a eucalyptusplantation is reduced because the eucalyptus are being cut and

m Ref. [24].

/year) Lorries delivery to the plant Land area required

3e5/year 1e3% within 1 km radius10e140/year 5e10% within 2 km radius150e500/year 1e3% within 5 km radius5e10/day 5e10% within 10 km radius25e50/day 2e5% within 50 km radius

J.D. Hunt et al. / Energy 101 (2016) 91e99 99

will consume less water. This results in a more efficient use ofwater resources.

2) During the first and second dry years, the water consumption ineucalyptus plantations will also be reduced because the euca-lyptus are being cut and will consume less water. However, afterthe third dry year the water consumption will increase becausethe plantations will grow at a faster rate.

5. Conclusion

This article presented a new scheme for storing energy in theform of eucalyptus plantations. During years that thermoelectricityis not highly demanded, biomass is accumulated in eucalyptusplantations. This biomass is then used to generate electricity duringyears when there is urgent need for thermoelectricity generation.

This scheme suits the Brazilian energy sector because Brazilgenerates most of its electricity with hydropower. There are twostrongly marked climate seasons, the dry season (MayeOctober)and the wet season (NovembereApril). As the new hydroelectricdams in the Amazon will not have storage reservoirs, Brazil willhave to generate thermoelectricity during the dry period. Anotherissue is that there are years with a lower rainfall average whichreduces the countries overall hydropower generation.

The Energy Crop Storage scheme can resolve this issuebecause during wet years, the biomass thermoelectric powerplants would only operate during the dry period and the euca-lyptus plantations will continue to grow. When there is an overalldry year, the thermoelectric power plants will then operate at fullcapacity throughout the whole year, consuming some of thebiomass stored in the eucalyptus plantations.

It was estimated that 30 GWgeneration of eucalyptus based ECSfor thermoelectric generation is needed to complement the excessgeneration during the wet period in the Amazon. This will increasethe Brazilian energy storage potential by 49.5%. In one year, thisscheme would be able to generate 26 TWh of biomass energystored per year. The estimated eucalyptus plantation land requiredto provide the above energetic services is 5.3 million hectares,which is 73.5% of the already existing eucalyptus plantation inBrazil.

The future of the biomass sector points in the direction of bio-refineries. The technology is in an advanced stage of maturity, andadoption by the domestic industry is feasible. This study foundseveral positive factors for business leverage linked to biorefineries,for example, the creation of opportunities to expand the portfolio ofindustrial products with higher added value, and the developmentof intellectual and industrial property for these new productsconnected to the sector [25].

Acknowledgements

We would like to thank CAPES/BRAZIL for the research grant aspart of the Science without Borders Program and the International

Virtual Institute for Global Change for the possibility to interactwith experts in the field.

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