Potentialities of energy generation from waste and feedstock produced by the agricultural sector in Brazil: The case of the State of Paraná

The State of Paraná contributes significantly for the Brazilian production of sugar cane, ethanol, soybeans and pigs. In addition to the current production of ethanol, the State has a huge potential for electricity, biodiesel and biogas production. This paper presents an overview of the current situation regarding energy generation from the agricultural sector in the State, an assessment of the potentialities of energy generation from sugar cane residues and pig agricultural chains, as well as an analysis of the socioeconomic factors underlying the availability of feedstock for biodiesel production. This study has shown that it is possible to expand the energy supply in the State using residual biomass from the sugar cane and pig production. On the other side, the biodiesel production increase in the State will depend on the expansion in the consumption of products that use the cake as raw material; the increase in the feedstock availability other than canola, castor beans and sunflower; the increase of the number of family farmers as feedstock providers, so as to ensure access for biodiesel producers to the Social Fuel Stamp.     

Sugarcane industry's socioeconomic impact in São Paulo,Brazil: A spatial dynamic panel approach

This study assesses the socioeconomic development impacts of the recent sugarcane industry expansion on municipalities in the Brazilian state of São Paulo over seven years, from 2005 through 2011. It was used as socioeconomic development indicator the Index of Municipal Development (IFDM), provided by the Federation of the State of Rio de Janeiro Industries (FIRJAN). A dynamic spatial panel model was built using the System Generalized Method of Moments (GMM-SYS) to assess the impacts of the sugarcane industry, caused by the expansion of both the cultivated area and the presence of ethanol and sugar processing plants. We found that the presence of a processing plant has a positive effect in the socioeconomic development of the municipality where the plant is located and in neighboring municipalities. Besides, we found a small negative relationship between increases in the amount of area devoted to sugarcane cultivation in a municipality and the IFDM value for that municipality, which can be explained by job losses in the farming sector, most likely by the recent mechanization process of sugarcane harvesting.     

The sustainability of ethanol production from sugarcane

The rapid expansion of ethanol production from sugarcane in Brazil has raised a number of questions regarding its negative consequences and sustainability. Positive impacts are the elimination of lead compounds from gasoline and the reduction of noxious emissions. There is also the reduction of CO₂ emissions, since sugarcane ethanol requires only a small amount of fossil fuels for its production, being thus a renewable fuel. These positive impacts are particularly noticeable in the air quality improvement of metropolitan areas but also in rural areas where mechanized harvesting of green cane is being introduced, eliminating the burning of sugarcane. Negative impacts such as future large-scale ethanol production from sugarcane might lead to the destruction or damage of high-biodiversity areas, deforestation, degradation or damaging of soils through the use of chemicals and soil decarbonization, water resources contamination or depletion, competition between food and fuel production decreasing food security and a worsening of labor conditions on the fields. These questions are discussed here, with the purpose of clarifying the sustainability aspects of ethanol production from sugarcane mainly in São Paulo State, where more than 60% of Brazil's sugarcane plantations are located and are responsible for 62% of ethanol production.     

Full chain energy analysis of fuel ethanol from cane molasses in Thailand

An analysis of energy performance and supply potential was performed to evaluate molasses utilization for fuel ethanol in Thailand. The Thai government recently has set up a production target of 1.925 million litres a day of sugar-based ethanol. The molasses-based ethanol (MoE) system involves three main segments: sugar cane cultivation, molasses generation, and ethanol conversion. Negative net energy value found for MoE is a consequence of not utilizing system co-products (e.g. stillage and cane trash) for energy. Taking into account only fossil fuel or petroleum inputs in the production cycle, the energy analysis provides results in favour of ethanol. A positive net energy of 5.95 MJ/L which corresponds to 39% energy gain shows that MoE is efficient as far as its potential to replace fossil fuels is concerned. Another encouraging result is that each MJ of petroleum inputs can produce 6.12 MJ of ethanol fuel. Regarding supply potential, if only the surplus molasses is utilized for ethanol, a shift of 8–10% sugar cane produce to fuel ethanol from its current use in sugar industry could be a probable solution.     

Sugar-ethanol-electricity co-generation in Hawai’i: An application of linear programming (LP) for optimizing strategies

This research develops a linear programming (LP) model to assess various options for sugar and biofuel production from sugarcane and other feedstock in Hawaii. More specifically, the study focuses on finding optimal sugar and biomass feedstock that would maximize producer profits in the production of sugar, ethanol and electricity. Feedstock included in the model were sugarcane, banagrass, energy cane and sweet sorghum. Given available land resources for growing energy crops on the island of Maui, four land resource scenarios were considered. If available land resources were used in the production of sugarcane and energy crops with added utilization of non-prime lands, Hawaii's ethanol goal for year 2020 could be achieved while maintaining two-thirds of Hawaii's current sugar production. Crop yields and unit production costs are key factors in determining optimal quantities of feedstock in the optimization model tested in this study.     

Synthesis and parameter optimization of a combined sugar and ethanol production process integrated with a CHP system

The combined sugar and ethanol production process from sugar cane is a paradigmatic application for energy integration strategies because of the high number of hot and cold streams involved, the external hot utility requirement at two temperature levels for juice evaporation and crystallization, and the electricity demand for juice extraction by milling. These conditions make it convenient to combine the sugar-cane process with a CHP system fuelled by bagasse, the main by-product from juice extraction. The strategies, tools and expertise on energy integration developed separately by the research teams authoring this paper are applied here jointly to optimize the synthesis and the design parameters of the process and of the total site starting from the basic idea of dissociating the heat exchanger network design problem from the total site synthesis problem. At first the minimization of the external heat requirement for the process alone is pursued and results show that a one third reduction can be achieved by optimal heat integration. Then the use of the by-product bagasse for on-site power generation is considered and two bagasse-fuelled CHP systems are optimized along with some parts of the sugar and ethanol production process in order to obtain maximum total site net power. Results show a variety of interesting scenarios of combined sugar, ethanol and electricity production plants with considerably high electricity output.     

Ethanol Production from Sugar Cane: Assessing the Possibilities of Improving Energy Efficiency through Exergetic Cost Analysis

The sugar and ethanol production is one of the most important economical activities in Brazil, mainly due its high efficiency and competitiveness. Ethanol production is done by a series of steps: juice extraction, treatment, fermentation, and distillation. The juice extraction and treatment is a common operation of both the sugar and ethanol industries. The process begins with the sugar cane juice extraction, usually done by mills, where the cane is compressed between large cylinders for the separation of the juice from the bagasse. Recently, a juice extraction system, called a diffuser, was introduced in some sugar and ethanol plants. In diffusers, after the sugar cane preparation stage was completed with knives and shredders, the cane passes through a bed where the juice is separated from bagasse by the addition of imbibition water and steam, resulting in a leaching process. The present study evaluates different possibilities of decreasing the thermal energy consumption through exergetic cost analysis. The base case is a traditional ethanol production plant, for which the unitary exergetic cost of ethanol and electrical energy are determined. In the following cases, two proposals were assessed: the use of the diffuser as an extraction system and the use of pinch technology to perform an energetic integration between distillation and extraction (diffuser) systems. The results of exergetic efficiency, irreversibility generation, and unitary exergetic cost of products of the three cases are analyzed and compared. The results show the feasibility of using diffusers and heat recovery to decrease thermal energy consumption in ethanol production plants.     

我国非粮燃料乙醇的原料资源量分析

目前世界燃料乙醇的生产原料约60%为甘蔗或甜菜等糖质原料、33%为玉米或小麦等淀粉质原料,而纤维质原料正日益受到重视。我国可用于生产燃料乙醇的非粮淀粉质原料主要有甘薯、木薯、蕉藕、葛根等。其中蕉藕目前尚未形成产业化生产;葛根原料价格高,不宜作为乙醇原料;甘薯归属粮食范畴;只有木薯是最适宜制燃料乙醇的非粮淀粉质原料。纤维质原料主要包括农作物秸秆、农林废弃物、木屑等,其中农作物秸秆是我国产量最大的非粮燃料乙醇原料。秸秆资源密度考虑,利用区域应主要集中在河南、山东、江苏等地,保守估计这3个省的秸秆量可供生产1117×104t乙醇。目前制约纤维质原料制乙醇的关键瓶颈之一是原料的收集、运输及供应保障,若没有国家大的政策扶持和资金补贴,纤维质原料因缺乏经济可行性而尚不具备工业化生产乙醇的条件。糖质原料主要有甘蔗、甜菜、甜高粱茎秆和菊芋。由于菊芋菊粉附加值高,不宜作乙醇原料;甘蔗、甜菜主要用于糖业,不会作为乙醇原料;从单位土地面积乙醇产量和原料成本、农民种植收益综合来看,甜高粱茎秆是适宜生产燃料乙醇的糖质原料。需要寻求产业化种植模式来落实资源总量,提高资源保障度;另一方面要进一步研究低成本、安全保质的茎秆储藏技术。     

Optimizing ethanol and bioelectricity production in sugarcane biorefineries in Brazil

In sugarcane biorefineries, the lignocellulosic portion of the sugarcane biomass (i.e. bagasse and cane trash) can be used as fuel for electricity production and/or feedstock for second generation (2G) ethanol. This study presents a techno-economic analysis of upgraded sugarcane biorefineries in Brazil, aiming at utilizing surplus bagasse and cane trash for electricity and/or ethanol production. The study investigates the trade-off on sugarcane biomass use for energy production: bioelectricity versus 2G ethanol production. The BeWhere mixed integer and spatially explicit model is used for evaluating the choice of technological options. Different scenarios are developed to find the optimal utilization of sugarcane biomass. The study finds that energy prices, type of electricity substituted, biofuel support and carbon tax, investment costs, and conversion efficiencies are the major factors influencing the technological choice. At the existing market and technological conditions applied in the upgraded biorefineries, 300 PJ y⁻¹ 2G ethanol could be optimally produced and exported to the EU, which corresponds to 2.5% of total transport fuel demand in the EU. This study provides a methodological framework on how to optimize the alternative use of agricultural residues and industrial co-products for energy production in agro-industries considering biomass supply chains, the pattern of domestic energy demand, and biofuel trade.     

Ethanol production and fuel substitution in Nepal—Opportunity to promote sustainable development and climate change mitigation

This paper explores the potential for ethanol production and fuel substitution in Nepal based on established sugarcane production, installed capacity for sugar and ethanol production, economic opportunities for the national economy, and potential to reduce greenhouse gas emissions. At present conditions, 18,045 m³ ethanol can be annually produced in Nepal without compromising the production of food products from sugar cane such as sugar, chaku and shakhar. The effects for the country can be manifold. As much as 14% of gasoline import reduction, and annual savings of US$ 10 million could be achieved through the introduction of the E20. The activity can provide an incentive for improved yields in sugarcane production, and help develop the industrial sector. This, in turn, will have a positive effect in terms of job and income generation in the rural areas where 85% of the population live. Improvement of agricultural practices for sugarcane could also have an indirect and positive effect on improving other agriculture activities. Furthermore, the use of ethanol in the transport sector will have a positive environmental effect while reducing CO₂ emissions and combating pollution in the Kathmandu Valley. Finally, the substitution of ethanol in transport will imply lower imports of oil products and less draining of resources from the Nepalese economy.     

Can increasing gasoline supply in the United States affect ethanol production in Brazil?

The increasing supply of non-conventional oil in the U.S. has changed the dynamics of crude oil market and the flow of oil products in the Atlantic Basin. The Gulf of Mexico (GoM) emerges as an exportation hub of oil products, contributing to a scenario in which gasoline prices tend to decline. Meanwhile, from 2010, the competitiveness of the Brazilian sugarcane ethanol has been ruptured by the country's gasoline price policy that had not followed international price parity. The political conjuncture of the U.S. incites high utilization rates of their refining system in the GoM. In this context the profitability of the ethanol business can be impacted in Brazil, by either the current policy of controlled domestic gasoline prices or a future scenario of declining gasoline international prices. Therefore, this study tests if this gasoline price scenario can compromise even more the competitiveness of the Brazilian ethanol. Particularly, for a scenario of falling prices, ethanol production in Brazil would be under strong pressure of gasoline supply coming from the U.S. This can impact Brazil's ethanol industry, whose development has been justified by climate change policies. In that sense, the paper also discusses the future opportunities and challenges for Brazil's ethanol industry.     

A simple rule for bioenergy conversion plant size optimisation: Bioethanol from sugar cane and sweet sorghum

Fuel ethanol from agricultural crops, “bioethanol”, is more expensive than petrol. Here we consider ways to reduce ethanol costs, by using mixed crops to extend the processing season and by optimising plant capacity. We derive a simple model of general applicability by balancing crop transport costs (which increase with plant size) against the (decreasing) production costs. We show that at the optimum, the cost of transporting crop, per unit quantity of alcohol, must be a predictable proportion of the unit cost of production, generally in the range 0.4–0.6. Under current Australian conditions, cane sugar and cane plus sweet sorghum bioethanol plants have optimum capacities around 245,000 and 175,000 kl/year, respectively. the model is equally applicable to any other bioenergy conversion plant which requires biomass to be transported from surrounding areas. The model also shows quantitatively how more efficient transport allows larger scale production, while lower production costs make smaller plants more economic.     

The benefits of ethanol use for hydrogen production in urban transportation

The purpose of this paper is to describe the benefits of sugar cane ethanol in Brazil, appointing the productivity of this type of fuel based on hectares of plantation, its carbon dioxide cycle and the contribution to reduce the greenhouse effect. In the following step the uses of ethanol for hydrogen production by steam reforming is analyzed and some comparison with natural gas steam reforming is performed. The sugar cane industry in Brazil, in a near future, in the hydrogen era, could be modified according to our purpose, since besides the production of sugar, and ethylic and anhydric alcohol, Brazilian sugar cane industry will also be able to produce biohydrogen.Fuel cells appear like a promising technology for energy generation. Among several technologies in the present, the PEMFC (proton exchange membrane fuel cell) is the most appropriate for vehicles application, because it combines durability, high power density, high efficiency, good response and it works at relatively low temperatures. Besides that it is easy to turn it on and off and it is able to support present vibration in vehicles. A PEMFC's problem is the need of noble catalysts like platinum. Another problem is that CO needs to be in low concentration, requiring a more clean hydrogen to avoid fuel cell deterioration.One part of this paper was developed in Stockholm, where there are some buses within the CUTE (clean urban transport for Europe) project that has been in operation with FC since January 2004. Another part was developed in Guaratinguetá, Brazil. Brazil intends to start up a program of FC buses. As conclusion, this paper shows the economical analysis comparing buses moved by fuel cells using hydrogen by different kinds of production. Electrolyze with wind turbine, natural gas steam reforming and ethanol steam reforming.     

Optimizing peracetic acid pretreatment conditions for improved simultaneous saccharification and co-fermentation (SSCF) of sugar cane bagasse to ethanol fuel

The use of several lignocellulosic materials for ethanol fuel production has been studied exhaustively in the U.S.A.. Strong environmental legislation has been driving efforts by enterprises, state agencies, and universities to make ethanol from biomass economically viable. Production costs for ethanol from biomass have been decreasing year by year as a consequence of this massive effort. Pretreatment, enzyme recovery, and development of efficient microorganisms are some promising areas of study for reducing process costs.Sugar cane bagasse constitutes the most important lignocellulosic material to be considered in Brazil as new technology such as the production of ethanol fuel. At present, most bagasse is burned, and because of its moisture content, has a low value fuel. Ethanol production would result in a value-added product. The bagasse is available at the sugar mill site at no additional cost because harvesting, transportation and storage costs are borne by the sugar production.The present paper presents an alternative pretreatment with low energy input where biomass is treated in a silo type system without need for expensive capitalization. Experimentally, ground sugar cane bagasse is placed in plastic bags and a peracetic acid solution is added to the biomass at concentrations of 0, 6, 9, 15, 21, 30, and 60% w/w of peracetic acid based on oven dried biomass. The ratio of solution to wood is 6:1; a seven day storage period had been used. Tests using hydrolyzing enzymes as an indicator for SSCF have been performed to evaluate the pretreatment efficiency.As an auxiliary method, a series of pre-pretreatments using stoichiometric amounts of sodium hydroxide and ammonium hydroxide based on 4-methyl-glucuronic acid and acetate content in the sugar cane bagasse have been performed before addition of peracetic acid. The alkaline solutions are added to the raw bagasse in a ratio of 17:1 solution to biomass and mixed for 24 hours at room temperature. Biomass is filtered and washed to a neutral pH before the peracetic acid addition.According to enzymatic hydrolysis results, peracetic acid is a powerful chemical for improving enzymatic digestibility in sugar cane bagasse with no need for using high temperatures. Basic pre-pretreatments are helpful in reducing peracetic acid requirements in the pretreatment.     

Quantitative analysis of feasibility of hydrous ethanol futures contracts in Brazil

Brazil's first ethanol futures contract, which was implemented in 2000, failed to offer sufficient liquidity to attract market agents. The purpose of this study is to determine whether the new ethanol futures contracts launched by BMF-BOVESPA in 2010 meet the requirements to render them feasible. The originality of this work stems from its approach in analyzing different cross-hedging possibilities in the food and energy chains. This analysis, which covers the period of May 2010 to April 2012, evaluates the degree of competition in the sector, the price volatility of the spot market, the price correlations between its possible substitutes, as well as the possibility of cross-hedging Brazil's ethanol with contracts in international futures markets and their potential degree of substitution. The results of this study indicate that the new configuration of BMF-BOVESPA ethanol futures contracts meets the most requirements for viability. Nevertheless, the ethanol distribution sector is relatively concentrated, which may limit the liquidity of BMF-BOVESPA ethanol futures contracts.     

Oil refining expansion criteria for Brazil

This paper assesses different strategies for the expansion of Brazil's oil refining segment, using criteria that range from energy security (reducing imports and vulnerability for key products) through to maximizing the profitability of this sector (boosting the output of higher value oil products) and adding value to Brazil's oil production (reducing exports of heavy acid oil). The development prospects are analyzed for conventional fuel production technology routes, sketching out three possible refining schemes for Brazilian oil and a GTL plant for producing gasoil from natural gas. Market scenario simulations indicate that investments will be required in Brazil's oil refining segment over and above those allocated to planned modifications in its current facilities, reducing the nation's vulnerability in terms of gasoil and petrochemical naphtha imports. Although not economically attractive, oil refining is a key activity that is crucial to oil company strategies. The decision to invest in this segment depends on local infrastructure conditions, environmental constraints and fuel specifications, in addition to oil company strategies, steady growth in demand and the definition of a government policy that eases institutional risks.     

Cellulase production using biomass feed stock and its application in lignocellulose saccharification for bio-ethanol production

A major constraint in the enzymatic saccharification of biomass for ethanol production is the cost of cellulase enzymes. Production cost of cellulases may be brought down by multifaceted approaches which include the use of cheap lignocellulosic substrates for fermentation production of the enzyme, and the use of cost efficient fermentation strategies like solid state fermentation (SSF). In the present study, cellulolytic enzymes for biomass hydrolysis were produced using solid state fermentation on wheat bran as substrate. Crude cellulase and a relatively glucose tolerant BGL were produced using fungi Trichoderma reesei RUT C30 and Aspergillus niger MTCC 7956, respectively. Saccharification of three different feed stock, i.e. sugar cane bagasse, rice straw and water hyacinth biomass was studied using the enzymes. Saccharification was performed with 50 FPU of cellulase and 10 U of β-glucosidase per gram of pretreated biomass. Highest yield of reducing sugars (26.3 g/L) was obtained from rice straw followed by sugar cane bagasse (17.79 g/L). The enzymatic hydrolysate of rice straw was used as substrate for ethanol production by Saccharomyces cerevisiae. The yield of ethanol was 0.093 g per gram of pretreated rice straw.     

Potential and costs for the production of electrolytic hydrogen in alcohol and sugar cane plants in the central and south regions of Brazil

This project verified the potential for the production of hydrogen via water electrolysis by using the exceeding electrical energy resultant from alcohol and sugar plants that use sugar cane bagasse as fuel. The studies were carried out in cogeneration plants authorized by the Electrical Energy National Agency (ANEEL). The processing history of sugar cane considered was based on the 2006/2007 harvests. The total bagasse produced, electrical energy generated and exceeding electrical energy in a year were calculated. It was obtained an average energy consumption value of 5.2 kWh Nm⁻³ and the hydrogen production costs regarding the amount of sugar cane processed that ranged from US$ 0.50 to US$ 0.75 Nm⁻³. The results pointed that the costs for the production of hydrogen via the bagasse exceeding energy are close to the production costs that use other sources of energy. As the energy generated from the bagasse is a renewable one, this alternative for the production of hydrogen is economical and environmentally viable.     

Impacts of a United States’ biofuel policy on New Zealand's agricultural sector

The rise in oil prices has spurred interest in biofuels. Policies in the United States like the renewable fuel standard (RFS) have led to an expansion of ethanol production, while the New Zealand government has mandated a minimum level of biofuel sales.The research used a partial equilibrium model of international trade to quantify the price and farmgate income effects of the US RFS policy. The goal was to examine the competition between food and biofuel production and to quantify the impact of the policy on the agricultural sector in New Zealand.The RFS policy has a significant impact on corn prices, but a small effect on livestock prices and production. There thus appears to be little conflict between food and fuel uses for corn at the level of the RFS mandate. New Zealand's pasture-based livestock sector benefits from the use of corn for ethanol production: it receives better prices for its products, but does not face the same input cost increases as competitors. The results suggest that New Zealand faces an interesting decision: it could support investment in biofuels research, or benefit from the biofuels boom through the indirect impacts on demand and prices for meat and milk.     

System expansion for handling co-products in LCA of sugar cane bio-energy systems: GHG consequences of using molasses for ethanol production

This study aims to establish a procedure for handling co-products in life cycle assessment (LCA) of a typical sugar cane system. The procedure is essential for environmental assessment of ethanol from molasses, a co-product of sugar which has long been used mainly for feed. We compare system expansion and two allocation procedures for estimating greenhouse gas (GHG) emissions of molasses ethanol. As seen from our results, system expansion yields the highest estimate among the three. However, no matter which procedure is used, a significant reduction of emissions from the fuel stage in the abatement scenario, which assumes implementation of substituting bioenergy for fossil-based energy to reduce GHG emissions, combined with a negligible level of emissions from the use stage, keeps the estimate of ethanol life cycle GHG emissions below that of gasoline. Pointing out that indirect land use change (ILUC) is a consequence of diverting molasses from feed to fuel, system expansion is the most adequate method when the purpose of the LCA is to support decision makers in weighing the options and consequences. As shown in the sensitivity analysis, an addition of carbon emissions from ILUC worsens the GHG balance of ethanol, with deforestation being a worst-case scenario where the fuel is no longer a net carbon saver but carbon emitter.