A carbon footprint assessment of multi‐output biorefineries with international biomass supply: a case study for the Netherlands

Australia is one of the major producers and exporter of agricultural products. Annually, Australian agriculture produces approximately 151 Tg CO2 equivalent emissions. The use of fossil fuels in crop cultivation, harvesting and transportation are considered as the primary source of these greenhouse gas (GHG) emissions. Moreover, agronomic management and crop residues left in the field also contribute to these GHG emissions. Alternative waste management practices include the use of crop residues and agro-wastes as feedstocks for bioenergy production. Anaerobic digestion is considered as sustainable environmental technology to convert industrial sugarcane residues to carbon dioxide (CO2) - neutral biogas. The biogas thus produced can be used to produce heat, electricity and upgrade to biomethane for vehicle use. The produced biomethane can replace the diesel consumption associated with GHG emission in cane transport. Sugarcane is one among the most cultivated crop in the world. Australia alone produced nearly 33.5 million tonnes of cane in 2018 (FAO 2018). These large production of sugarcane lead to an increase in crop residues and agro-wastes from the sugarcane industry. In this study, an investigation regarding the anaerobic co-digestion of crop residues and agro-wastes from sugarcane industry viz, sugarcane trash (SCT) or sugarcane bagasse (SCB) with chicken manure (CM) was investigated in a batch experiment at 37 °C. In spite of various researches conducted till date about co-digestion of lignocellulosic waste with manure, no research data was available regarding the effect of feed ratio on co-digestion of SCT/SCB with CM. This research gap was investigated in this study. In addition to this, steam explosion pre-treatment of SCT/SCB was included to investigate how the pre-treatment influence methane yield among different feed ratios of SCT/SCB with CM. At first, SCT and SCB were subjected to steam explosion pre-treatment (steam impregnation at 130 °C for 5 minutes followed by steam explosion). Later, two sets of biochemical methane potential (BMP) tests were conducted at an Inoculum to Substrate Ratio (ISR) of 2. Co-digestion of untreated and steam exploded SCT or SCB with CM was investigated at feed ratios of 75:25, 50:50 and 25:75 on volatile solids (VS) basis. Assays with 100% untreated and steam exploded SCT or SCB were also included. Chemical analysis revealed that the steam explosion improved the VS content in pre-treated biomass compared with untreated biomass. The increase in VS was 1.6% and 5.7% in SCT and SCB, respectively. On the other hand, a slight reduction in total solids (TS) of nearly 4% and 1% were observed in the case of SCT and SCB, respectively. BMP results showed that the steam explosion had a profound effect on the methane production rates and yields, especially for SCB than SCT. Methane (CH4) yields of 201.8 and 199 ml CH4/gVSadded were obtained during the mono-digestion of untreated SCT and SCB, respectively. The corresponding values for 100% steam-exploded SCT and SCB were 207.5 and 225.6 ml/gVSadded, respectively. In comparison to mono-digestion, the co-digestion of SCB or SCT with CM did not improve the methane yields. Nevertheless, pre-treatment improved the methane production rates and yields of pre-treated biomass than untreated biomass. Among the studied feed ratios, best methane yields of 206.5 ml/gVSadded were obtained when steam-exploded SCT was co-digested with CM at 75:25 ratio. However, methane yields decreased with an increase in the amount of CM added. SCB also showed a similar trend. The best methane yield of 199.5 ml/gVSadded was obtained when steam-exploded SCB was co-digested with CM at 75:25 ratio. Among the tested feed ratios, all co-digestion mixtures except for 75:25 and 50:50 ratios of untreated SCT to CM showed synergistic effects. The best synergistic effect of 18.57% was observed when untreated SCB was co-digested with CM at 25:75 ratio. Kinetic modelling results confirmed that the steam explosion pre-treatment improved the methane production rates and yields by increasing the hydrolysis rate constant values. However, a higher hydrolysis rate constant was noticed for SCT than SCB. The highest hydrolysis rate constant of 0.16 d-1 was achieved at feed ratios of 50:50 and 25:75 of pre-treated SCT:CM. Interestingly, more than 75% of methane in pre-treated assays was produced by Day 11. The study thus suggests that the steam explosion can improve the methane production rates, yields and productivity of SCT and SCB. However, the use of CM as co-substrate did not improve the methane yields when compared to the mono-digestion of SCT or SCB, but a positive synergism was evident in most of the co-digestion feed ratios.

The United States of America is making great efforts to transform the renewable and abundant biomass resources into cost-competitive, high-performance biofuels, bioproducts, and biopower. This is the key to increase domestic production of transportation fuels and renewable energy, and reduce greenhouse gas and other pollutant emissions. This dissertation focuses specifically on assessing the life cycle environmental impacts of biofuels and bioenergy produced from renewable feedstocks, such as lignocellulosic biomass, renewable oils and fats. The first part of the dissertation presents the life cycle greenhouse gas (GHG) emissions and energy demands of renewable diesel (RD) and hydroprocessed jet fuels (HRJ). The feedstocks include soybean, camelina, field pennycress, jatropha, algae, tallow and etc. Results show that RD and HRJ produced from these feedstocks reduce GHG emissions by over 50% compared to comparably performing petroleum fuels. Fossil energy requirements are also significantly reduced. The second part of this dissertation discusses the life cycle GHG emissions, energy demands and other environmental aspects of pyrolysis oil as well as pyrolysis oil derived biofuels and bioenergy. The feedstocks include waste materials such as sawmill residues, logging residues, sugarcane bagasse and corn stover, and short rotation forestry feedstocks such as hybrid poplar and willow. These LCA results show that as much as 98% GHG emission savings is possible relative to a petroleum heavy fuel oil. Life cycle GHG savings of 77 to 99% were estimated for power generation from pyrolysis oil combustion relative to fossil fuels combustion for electricity, depending on the biomass feedstock and combustion technologies used. Transportation fuels hydroprocessed from pyrolysis oil show over 60% of GHG reductions compared to petroleum gasoline and diesel. The energy required to produce pyrolysis oil and pyrolysis oil derived biofuels and bioelectricity are mainly from renewable biomass, as opposed to fossil energy. Other environmental benefits include human health, ecosystem quality and fossil resources. The third part of the dissertation addresses the direct land use change (dLUC) impact of forest based biofuels and bioenergy. An intensive harvest of aspen in Michigan is investigated to understand the GHG mitigation with biofuels and bioenergy production. The study shows that the intensive harvest of aspen in MI compared to business as usual (BAU) harvesting can produce 18.5 billion gallons of ethanol to blend with gasoline for the transport sector over the next 250 years, or 32.2 billion gallons of bio-oil by the fast pyrolysis process, which can be combusted to generate electricity or

Chapter 8 - Challenges and Opportunities for International Trade in Forest Biomass

Renewable energy, including biomass, has received increasing attention because of worldwide efforts to prevent global warming and alleviate soaring oil prices. When biomass is used as an energy source, for example, it is converted to ethanol as an alternative to gasoline or burned in a boiler to generate heat and power. Cereals such as corn are promising candidates for easily convertible biomass for ethanol production. However, it is possible that the supply of such potential biofuels will become unstable because of conflicts with food production. For example, corn prices have doubled or have reached levels not seen in many years11. In contrast, woody biomass is inedible and thus may be a promising candidate as a future renewable energy source. Woody biomass can be collected in large amounts from forests or as a by-product of the forest industry. However, forests are unevenly distributed throughout the world, and so the distribution of woody biomass is uneven. Countries belonging to the Association of Southeast Asian Nations (ASEAN) have a vast range and abundance of forest resources. However, these resources have been considerably reduced because of unrestrained logging in some countries. Sustainable forest management is necessary for the continued use of the available biomass as a renewable energy source. Our objective was to investigate the current status of the use and consumption of woody biomass to discuss future possibilities and difficulties in the use of woody biomass as an energy source. We focused on Cambodia, Indonesia, Laos, Malaysia, the Philippines, Thailand, and Vietnam. Hereafter, our use of the term “ASEAN countries,” unless otherwise specified, refers to these seven countries.

Wood biomass including forest residues, waste wood, and construction residuals has been widely generated in Korea, but forest biomass from the National Forest Management Operation Project plays a big role in generating wood biomass. Unfortunately the promotion policy of woody energy organized by the Forest Service in Korea concentrates more on demand creation rather than on supply expansion. Therefore, in order to utilize insufficient wood resources effectively, it is greatly required to develop uses for maximizing their added value. In particular, more attention to the use of the second generation biomass has been paid in foreign countries because there is a threshold that the first generation biomass cannot produce enough biofuel without threatening food supplies and biodiversity. In Korea, wood pellets are regarded as the alternative clean fuels to oils and coals that emit green house gases into the atmosphere. However, using wood as pellet raw materials can not be an economic way because the value of wood disappears right after burning in the boiler in spite of its contribution to the decrease of carbon emission. Differently from wood pellets, kraft pulping process using woody biomass produces black liquor as a by-product which can be used to generate electricity, bioenergy and biochemicals through gasification. Thus, it can be more economical to make a torrefaction of lignocellulosic biomass such as low-quality wood and agricultural leftovers as raw materials of pellets.

Finland considers energy production from woody biomass as an efficient energy planning strategy to increase the domestic renewable energy production in order to substitute fossil fuel consumption and reduce greenhouse gas emissions. Consequently, a number of developmental activities are implemented in the country, and one of them is the installation of second generation liquid biofuel demonstration plants. In this study, two gasification-based biomass conversion technologies, methanol and combined heat and power (CHP) production, are assessed for commercialization. Spatial information on forest resources, sawmill residues, existing biomass-based industries, energy demand regions, possible plant locations, and a transport network of Eastern Finland is fed into a geographically explicit Mixed Integer Programming model to minimize the costs of the entire supply chain which includes the biomass supply, biomass and biofuel transportation, biomass conversion, energy distribution, and emissions. The model generates a solution by determining the optimal number, locations, and technology mix of bioenergy production plants. Scenarios were created with a focus on biomass and energy demand, plant characteristics, and cost variations. The model results state that the biomass supply and high energy demand are found to have a profound influence on the potential bioenergy production plant locations. The results show that methanol can be produced in Eastern Finland under current market conditions at an average cost of 0.22 €/l with heat sales (0.34 €/l without heat sales). The introduction of energy policy tools, like cost for carbon, showed a significant influence on the choice of technology and CO2 emission reductions. The results revealed that the methanol technology was preferred over the CHP technology at higher carbon dioxide cost (>145 €/tCO2). The results indicate that two methanol plants (360 MWbiomass) are needed to be built to meet the transport fuel demand of Eastern Finland.

World energy consumption is at an all-time high and is projected to continue growing for the foreseeable future. Currently, much of the energy that is produced comes from non-renewable fossil energy sources, which includes the burden of increased greenhouse gas emissions and the fear of energy insecurity. Woody biomass is being considered as a material that can be utilized to reduce the burden caused by fossil energy. While the technical capability to convert woody biomass to energy has been known for a long period of time, the cost of the feedstock has been considered too costly to be implemented in a large commercial scale. Increasing the use of woody biomass as an energy source requires that the supply chains are setup in a way that minimizes cost, the locational factors that lead to development are understood, the facilities are located in the most favorable locations and local resource assessments can be made.;A mixed integer linear programming model to efficiently configure woody biomass supply chain configurations and optimize the harvest, extraction, transport, storage and preprocessing of the woody biomass resources to provide the lowest possible delivered price. The characteristics of woody biomass, such as spatial distribution and low bulk density, tend to make collection and transport difficult as compared to traditional energy sources. These factors, as well as others, have an adverse effect on the cost of the feedstock. The average delivered cost was found to be between {dollar}64.69-98.31 dry Mg for an annual demand of 180,000 dry Mg. The effect of resource availability and required demand was examined to determine the impact that each would have on the total cost.;The use of woody biomass for energy has been suggested as a way to improve rural economies through job creation, reduction of energy costs and regional development. This study examined existing wood using bio-energy facilities in the northeastern United States to define the drivers of establishment of bio-energy projects. Using a spatial econometric framework, a spatial autoregressive probit model was estimated based on the Bayesian methods to define the factors that impact the location of wood using bio-energy facilities in the United States. Through the analysis it was found that the energy policy of the state is the biggest driver of the choice of location for bioenergy facilities.;The choice of site is of great importance when trying to meet the goal of producing cost-effective biofuels, due to the spatial dispersion of

Attitudinal and revenue effects on non-industrial private forest owners' willingness-to-harvest timber and woody biomass

Performance estimation of energy consumption and carbon dioxide emissions for sustainable development in Baltic Sea countries

Fossil fuel reserve is declining gradually which results in serious scarcity of fuels and chemicals across the globe. In addition, fossil fuels’ versatile usage is also responsible for the ever-increasing global warming. All together a potential solution to those two problems could be the use of lignocellulosic biomass for fuel production because this alternative energy source is renewable, inexpensive, and readily available. Moreover, this biomass has neutral emission during the total biomass conversion process for fuels and chemicals coproduction. This chapter discusses bioethanol production from lignocellulosic biomass in two conversion routes - biochemical and hybrid conversion (combination of thermochemical and biochemical conversion) route. In the first biorefinery route, non-woody lignocellulosic biomass is converted into bioethanol through a biochemical conversion process that involves the conversion of biomass carbohydrates to sugars and subsequent fermentation by genetically modified Saccharomyces cerevisiae to bioethanol. The second biorefinery route uses gasification and consecutive synthesis gas fermentation in presence of Clostridium species for bioethanol production from the woody lignocellulosic biomass. In each route, the biomass pretreatment process, biomass sugar conversion process, and down-stream separation process are discussed in detail. Pretreatment processes by microbial consortia are discussed to show their impact on biomass crystallinity reduction and surface area increase in first route. Then separate hydrolysis and fermentation (SHF) process is utilized to hydrolyze lignocellulosic sugar and finally fermentation of all soluble sugars to bioethanol is discussed in the biochemical conversion process. On the contrary, in hybrid conversion process, gasification of woody biomass is carried out at first and later synthesis gas fermentation is discussed for bioethanol production. As a result, this chapter enables one to understand the details of process design steps required for second generation bioethanol production based on two large microbial consortia, genetically modified S. cerevisiae yeast and Clostridium bacteria species.

BackgroundTo be socially robust, renewable energy policies aiming at achieving a low-carbon society require public support. Woody biomass is an important renewable energy source. It accounts for a large share of the renewable energy consumption in several EU countries. However, its sustainability credentials are contested. Little is known as yet about how the public perceives woody biomass. This paper aims to examine the public’s intention to vote for continued use of woody biomass, and to find out whether this voting intention can be explained using the cognitive hierarchy model. This model posits that values, attitudes and beliefs predict higher order cognitions like intention. We extend the model by including an additional variable (perceived benefit). Although the model is widely used in connection with natural resource management issues, it has not yet been applied to the case of increasingly contested energy sources like woody biomass. We use Denmark as a case study given that woody biomass makes up the largest share of the renewable energy mix in the country.ResultsResults of a nationwide questionnaire-based survey of the general public show that a large proportion of Danes are undecided about their attitudes towards, and their intention to vote for, woody biomass. Structural equation modeling results show that belief in the mitigation potential of woody biomass has a significant positive effect on both attitudes and voting intention. Altruistic and egoistic values have a significant positive effect on attitudes, which in turn have a significant positive influence on voting intention. We also confirm the mediating role of attitudes.ConclusionsUnderstanding public opinion-making processes can help to promote environmental decision-making that takes due account of public perceptions of the ways in which energy transitions come about. The cognitive hierarchy model is an apt framework with which to predict voting intention in the context of contested energy sources.

Woody biomass has gained increased attention as a source of renewable energy. However, its categorization as a sustainable source of energy remains controversial, as its carbon neutrality depends on its end use, moisture content, bulk density, and the distance between the source of biomass and its end use. Due to these mediating factors, policies largely shape its sustainability and ability to mitigate emissions. This paper organizes and evaluates the current state of research through a systematic review of global literature from 2011 to 2021 (n = 345) on the governance of the production, transportation, sale, and use of woody biomass for energy. Peer-reviewed literature emphasizes the role of woody biomass as a decentralized energy source for individual households and communities, focusing on its harvest, transport, and localized energy conversion. Policies primarily address land management and energy infrastructure rather than direct emissions reduction. Research gaps in policy within the Global South underscore the need to examine biomass regulation in regions with limited energy diversity. The key factors that drive the sustainable uptake of woody biomass include strict sustainability criteria, fiscal incentives, technological development, and wood utilization from across its value chain. Effective policy implementation increases rural employment, boosts rural economies, provides energy security to remote areas, improves overall environmental sustainability, reduces emissions, and improves land management practices. Our systematic review reveals that future research should focus on improving conversion efficiencies in small-scale systems, reducing emissions in the international trade of woody biomass, and using the wood value chain to increase the profitability of bioenergy products.

Using life-cycle inventory production data, the net global warming potential (GWP) of a typical inland Northwest softwood lumber mill was evaluated for a variety of fuel types used as boiler inputs and for electricity generation. Results focused on reductions in carbon emissions in terms of GWP relative to natural gas as the fossil alternative. Woody feedstocks included mill residues, forest residuals, and wood pellets. In all fuel-substitution scenarios, increasing the use of biomass for heat generation decreased GWP. Using woody biofuels for electricity production is somewhat less effective in lowering carbon emissions than when used for heat energy. Heat generation at the mill under the current practice of using about half self-generated mill residues and half natural gas resulted in a 35 percent reduction in GWP over 100 percent natural gas. The greatest reduction in GWP (66%) was from increased use of forest residuals for heat energy, eliminating the use of fossil fuels as a direct heating fuel at the mill. We summarize the results by documenting that greater use of woody biomass for heat energy will reduce carbon emissions over fossil-based fuels.

Processing biomass into multifunctional products can contribute to food, feed, and energy security while also mitigating climate change. However, biorefinery products nevertheless impact the environment, and this influence needs to be properly assessed to minimize the burden. Life cycle assessment (LCA) is often used to calculate environmental footprints of products, but distributing the burdens among the different biorefinery products is a challenge. A particular complexity arises when the outputs are a combination of energy carrying no mass, and mass carrying no energy, where neither an allocation based on mass nor on energy would be appropriate. A novel hybrid mass–energy (HMEN) allocation scheme for dealing with multifunctionality problems in biorefineries was developed and applied to five biorefinery concepts. The results were compared to results of other allocation methods in LCA. The reductions in energy use and GHG emissions from using the biorefinery's biofuels were also quantified. HMEN fairly distributed impacts among biorefinery products and did not change the order of the products in terms of the level of the pollution caused. The allocation factors for HMEN fell between mass and economic allocation factors and were comparable to energy allocation factors. Where the mass or the energy allocation failed to attribute burdens, HMEN addressed this shortcoming by assigning impacts to nonmass or to nonenergy products. Under the partitioning methods and regardless of the feedstock used, bioethanol reduced GHG by 72–98% relative to gasoline. The GHG savings were 196% under the substitution method, but no GHG savings occurred for sugar beet bioethanol under the surplus method. Bioethanol from cellulosic crops had lower energy use and GHG emissions than from sugar beet, regardless of the allocation method used. HMEN solves multifunctional problems in biorefineries and can be applied to other complex refinery systems. LCA practitioners are encouraged to further test this method in other case studies.

Woody biomass is a renewable energy feedstock with the potential to reduce current use of nonrenewable fossil fuels. We estimated the physical availability of woody biomass for cocombustion at coal-fired electricity plants in the 20-state US northern region. First, we estimated the total amount of woody biomass needed to replace total annual coal-based electricity consumption at the state level to provide a representation of the potential energy footprints associated with using woody biomass for electric energy. If all woody biomass available were used for electric generation it could replace no more than 19% of coal-based electric generation or 11% of total electric energy generation. Second, we examined annual woody biomass increment at the state level in a series of concentric circles around existing coal-fired electricity plants to examine some of the opportunities and limitations associated with using woody biomass for cofiring at those plants to coincide with state-level renewable portfolio standards. On average, an individual coal-fired power electricity plant could theoretically replace 10% of annual coal use if it obtained 30% of the net annual woody biomass increment within a 34-km radius of the plant. In reality, the irregular spatial distribution of coal-fired power plants means potential biomass supply zones overlap and would greatly diminish opportunities for cofiring with biomass, numerous other regulatory, economic, and social considerations notwithstanding. Given that woody biomass use for electricity will be limited to selected locations, use of woody biomass for energy should be complementary with other forest conservation goals.