Supply chain optimization of residual forestry biomass for bioenergy production: The case study of Portugal

Within a large set of renewable energies being explored to tackle energy sourcing problems, bioenergy can represent an attractive solution if effectively managed. The supply chain design supported by mathematical programming can be used as a decision support tool to the successful bioenergy production systems establishment. This strategic decision problem is addressed in this paper where we intent to study the design of the residual forestry biomass to bioelectricity production in the Portuguese context. In order to contribute to attain better solutions a mixed integer linear programming (MILP) model is developed and applied in order to optimize the design and planning of the bioenergy supply chain. While minimizing the total supply chain cost the production energy facilities capacity and location are defined. The model also includes the optimal selection of biomass amounts and sources, the transportation modes selection, and links that must be established for biomass transportation and products delivers to markets. Results illustrate the positive contribution of the mathematical programming approach to achieve viable economic solutions. Sensitivity analysis on the most uncertain parameters was performed: biomass availability, transportation costs, fixed operating costs and investment costs.     

Energy policy and the role of bioenergy in Poland

Poland, as many other countries, has ambitions to increase the use of renewable energy sources. In this paper, we review the current status of bioenergy in Poland and make a critical assessment of the prospects for increasing the share of bioenergy in energy supply, including policy implications. Bioenergy use was about 4% (165 PJ) of primary energy use (3900 PJ) and 95% of renewable energy use (174 PJ) in 2003, mainly as firewood in the domestic sector. Targets have been set to increase the contribution of renewable energy to 7.5% in 2010, in accordance with the EU accession treaty, and to 14% in 2020. Bioenergy is expected to be the main contributor to reaching those targets. From a resource perspective, the use of bioenergy could at least double in the near term if straw, forestry residues, wood-waste, energy crops, biogas, and used wood were used for energy purposes. The long-term potential, assuming short rotation forestry on potentially available agricultural land is about one-third, or 1400 PJ, of current total primary energy use. However, in the near term, Poland is lacking fundamental driving forces for increasing the use of bioenergy (e.g., for meeting demand increases, improving supply security, or further reducing sulphur or greenhouse gas emissions). There is yet no coherent policy or strategy for supporting bioenergy. Co-firing with coal in large plants is an interesting option for creating demand and facilitating the development of a market for bioenergy. The renewable electricity quota obligation is likely to promote such co-firing but promising applications of bioenergy are also found in small- and medium-scale applications for heat production. Carbon taxes and, or, other financial support schemes targeted also at the heating sector are necessary in the near term in order to reach the 7.5% target. In addition, there is a need to support the development of supply infrastructure, change certain practices in forestry, coordinate RD&D efforts, and support general capacity building. The greatest challenge for the longer term lies in reforming and restructuring the agricultural sector.     

The energy forestry production systems

When growing and using energy forests a long chain of steps is taken: choice of site, site characterization, amelioration, choice of plant material and spacing, land preparation, planting, management, harvest and handling, transport, conversion, production of hot water and electricity.

The economics of energy forestry must be improved to make the whole concept viable. Although the economics need strengthening, it has been agreed that energy forestry is one of the most promising alternatives to cereal crops on farm land. There are two main ways to improve the economics: to increase production of stemwood per area and time, and to lower the costs of production. Good achievements along these routes have been reached over the last three years. Improving each step in growing is being achieved gradually. Lowering the costs is a more stepwise process, for example as was the case when a modified maize harvester proved to work surprisingly well as an energy forestry harvester.

Introductary work done during the three-year period indicates that expert systems or decision support systems may play an important role to share and use the knowledge on energy forestry production systems. For immediate use, a handbook on how to grow short rotation forests has been made published.     

Decentralised bioenergy systems: A review of opportunities and threats

Decentralised bioenergy systems are receiving increasing attention due to the potential ability to support local development, create local employment, and contribute to climate change mitigation. These issues, along with other bioenergy sustainability issues, are reviewed through eighteen international case studies with the objective of identifying opportunities and threats to decentralised bioenergy systems. The case studies were selected based on feedstock type, bioenergy type, production capacity, synergistic alliances, ownership structure and physical locations. This variation was used to provide a basis for evaluating opportunities and threats from different contexts. Commercial viability remains the primary concern for the sustainability of decentralised bioenergy systems. There are, however, opportunities for compounding benefits through integrating small scale decentralised bioenergy systems with other production systems. Integrated production, including closed loop models, allow waste materials from one process to be used as inputs in other production processes, and thereby increasing economic, social and environmental outcomes. Synergistic opportunities along the bioenergy production chain, which include feedstock production, bioenergy marketing and distribution could also be exploited by communities and other investors to minimise decentralised production risk.     

Impacts of policy means for increased use of forest-based bioenergy in Norway—A spatial partial equilibrium analysis

Like the European Union (EU), Norway has defined quite ambitious targets regarding increased use of bioenergy. However, the bioenergy market develops relatively slowly, and stronger policies seem necessary to reach the targets. This study analyses how different policy means, high on the agenda in the Norwegian energy debate, may affect the use of forest-based bioenergy in Norway. The means studied are (i) subsidies reducing investment costs of district heating installations, (ii) deposit grant for replacement of oil burners with burners based on bioenergy (iii) feed-in supporting energy production in district heating based on bioenergy. The study is based on a regionalised partial equilibrium model covering forestry, forest industries and the bioenergy sector. The advantage of this methodology is that it allows for assessments of the economic potential of bioenergy under different policy alternatives, taking into account the competition for raw materials from the forest industries, regional differences regarding heat demand and wood fibre supply, as well as important spatial aspects connected to inter-regional transport and trade of wood.

The results of the study give medium-term projections for bioenergy use in Norway under different bioenergy policy regimes. Some investments in bioburners in central heating systems and new district heating based on bioenergy are profitable at the current energy prices, but policy incentives in terms of grants, subsidies or feed-in systems make it possible to overcome inertia in investments decisions and provide substantial increase in the supply of bioenergy. The results show that the analysed policy means are effective at the current energy price levels and have a significant impact on bioenergy production. While some results are specific to Norway, other results and the methodology used are of more general value also to other European countries.     

BECCS in South Korea—Analyzing the negative emissions potential of bioenergy as a mitigation tool

The objective of this study is to analyze the in situ BECCS capacity for green-field bioenergy plants in South Korea. The technical assessment is used to support a policy discussion on the suitability of BECCS as a mitigation tool. We examined the technical potential of bioenergy production from domestic forest biomass. In a first step, the biophysical global forestry model (G4M) was applied to estimate biomass availability. In a second step, the results from G4M were used as input data to the engineering model BeWhere, which optimizes scaling and location of combined heat and power plants (CHP). The geographically explicit locations and capacities obtained for forest-based bioenergy plants were then overlaid with a geological suitability map for carbon storage. From this, a theoretical potential for in situ BECCS was derived. Results indicate that, given the abundant forest cover in South Korea, there is substantial potential for bioenergy production, which could contribute not only to substituting emissions from fossil fuels but also to meeting the targets of the country's commitments under any climate change mitigation agreement. However, there seems to be only limited potential for direct in situ carbon storage in South Korea.     

Integration of bioenergy systems into UK agriculture–New options for management of nitrogen flows

The large flow of reactive nitrogen (N) through agriculture causes negative environmental impacts, pointing to a need for changes in agricultural practices. At the same time, agriculture is expected to provide biomass to support the increasing demand from the UK bioenergy sector. A high-level aggregated model of the agricultural system in the UK was developed, which maintains the existing level of food and livestock production and at the same time increases N recirculation. Integrating three different bioenergy sub-systems into the agricultural system was an essential component of the model development. Cellulosic bioenergy crops were located in the landscape as vegetation filters to intercept and capture N and thereby reduce N leaching. Efficient collection and digestion of manure produced organic N fertiliser and biogas. Efficient forage production for cattle allowed further cultivation of bioenergy plants. Five implementation scenarios were developed to clarify the contribution of these bioenergy sub-systems to improved N management. The results point to a significant potential for improving the productive use of reactive N and for decreasing N losses to water and air. The interception and recirculation of N presently leaching from arable fields is assessed as the most important option. It is also important to increase recirculation of N in manure and in bioenergy system by-flows. Besides mitigating the environmental impacts of agriculture these measures reduce the requirements for newly synthesised N fertilisers. A systems perspective on N, agriculture, and bioenergy systems facilitates N recirculation and promotes effective N use, reducing the need for additional N inputs.     

The potential for Eucalyptus as a wood fuel in the UK

Considerable potential exists in the UK for utilising woody biomass, grown under short rotation forestry management systems, to produce electricity or heat. There are benefits to using biomass in generating heat and power the main environmental benefit being from substituting for fossil fuel combustion and consequent carbon emissions. Woody biomass production in short rotation forestry involves growing single stemmed trees rather than coppice over rotations of between 10 and 15 years. Eucalypts are particularly suited to such biomass production as they exhibit relatively high wood density, have suitable chemical characteristics, exhibit low moisture content and can be easily harvested all year around using conventional machinery if single-stemmed growth form is maintained.The UK has a climate that is not well suited to the majority of eucalypts. However, there is a small number of eucalypt species that can withstand the stresses caused by frozen ground and desiccating winds or sub-zero temperatures that can occur. These species are from more southern latitudes and high altitude areas of Australia. However, even the most cold resistant species can be damaged by UK winter climate extremes and therefore careful matching of species to site environmental constraints is critical. Informed decision making is made problematic by the small area and limited distribution of current planting, although it is clear that particularly cold areas and for most species, sites with poor drainage should be generally avoided. This article provides a discussion of the potential of, and constraints to, using eucalypts for biomass in the UK and provides a tentative list of recommended species, their potential growth rates and their advantages and disadvantages.     

Combining bioenergy and food security: An approach and rapid appraisal to guide bioenergy policy formulation

In the bioenergy discourse that ties energy and agricultural markets closely together, evidence based policy formulation is key to ensure integrated food and energy systems are developed when viable. Bioenergy is a particularly complex form of renewable energy as it covers a broad range of disciplines thus requiring a multidisciplinary approach to ensure viability. If built in a specific manner it has the option to target and provide investments in agriculture, a key sector for a number of developing economies.Due to the complexity of the issue, generating information, especially when resources are limited, can be cumbersome. We present a multidisciplinary approach, the Bioenergy and Food Security (BEFS) Rapid Appraisal, that can provide a first level of information within the decision making process.The analysis within the BEFS Rapid Appraisal defines the country context, estimates the biomass available for bioenergy production and ties this amount to specific bioenergy supply chains. Available biomass originating from agriculture is calculated net of current and foreseen uses and needs, thus accounting for food security. The bioenergy production potential is evaluated by quantifying the feedstock available, identifying income and employment opportunities, and energy access options. We present an application of the BEFS Rapid Appraisal for rural electrification options in Malawi.     

Optimization of bioenergy yield from cultivated land in Denmark

A cost minimization model for supply of starch, oil, sugar, grassy and woody biomass for bioenergy in Denmark was developed using linear programming. The model includes biomass supply from annual crops on arable land, short rotation forestry (willow) and plantation forestry. Crop area distributions were simulated using cost data for year 2005. Five scenarios with different constraints, e.g. on food and feed supply and on nitrogen balance were considered focusing on: a) constraints as the year 2005, b) landscape aesthetics and biodiversity c) groundwater protection, d) maintaining current food and feed production, or e) on site carbon sequestration. In addition, two oil price levels were considered. The crop area distributions differed between scenarios and were affected by changing fossil oil prices up to index 300 (using 55$ per barrel in 2005 as index = 100). The bioenergy supply (district heating, electric power, biogas, RME or bioethanol) varied between 56 PJ in the “2005” scenario at oil index 100 and 158 PJ at oil index 300 in the groundwater scenario. Our simple model demonstrates the effect of prioritizing multiple uses of land resources for food, feed or bioenergy, while maintaining a low nitrogen load to the environment. In conclusion, even after drastic landuse changes the bioenergy supply as final energy will not exceed 184 PJ annually (including 26 PJ processed biowaste sources) by far lower than the annual domestic total energy consumption ranging between 800 and 850 PJ yr^?1.     

Spatially explicit assessment of local biomass availability for distributed biogas production via anaerobic co-digestion - Mediterranean case study

Renewable energies, especially energy from biomass, contribute to the sustainable development of the territory. Simultaneously, by using biomass to produce bioenergy, bioreproductive land is devoted to supply energy. As the bioreproductive land area on the European level is decreasing, bioenergy competes against other demands like the production of food, industrial resources or cultural goods and services, among others, thus the correct assessment of the available local potential is important for local and regional planning. Moreover, bioenergy system being a socio-ecological system requires integrated approaches for the evaluation of the factors, components and interactions of such a system, considering that agriculture presents one of the major drivers of the land use change and biodiversity loss. Therefore, this work was focused on the development of the approach for and on the assessment of biogas potentials to provide a support for decision-makers and bioenergy industry at a local scale. The approach exploits the spatial relations among territorial units (i.e., a contiguity analysis), and integrates time series of continuous and discrete data. It is based on the analytic hierarchy process (AHP) combined with GIS-based analysis, and permitted to develop a territorial information system in support for biogas planning, perform analysis of feedstock for biogas from different sources potential and produce plausible scenarios for identification of biogas suitable territorial clusters; the analysis of the tradeoffs between the use of different local sources of the feedstock for biogas production are discussed as well.     

Sustainability impact assessment for local energy supplies' development – The case of the alpine area of Lake Como,Italy

The development of distributed energy systems has important environmental, social and economic implications. Local decision-making processes must be guided by a careful evaluation of the sustainability of production chains and alternative choices. The aim of this study is to explore if and how an integrated assessment can quantify the extent to which bioenergy supply chain development contributes to rural development and energy policy objectives. We applied a Sustainability Impact Assessment (SIA) for local bioenergy development in the alpine area of Lake Como (Italy). We modeled the local bioenergy chain in 2008 and eleven scenarios considering different biomass utilizations, mechanization levels, combustion technologies, and subsidies schemes at 2020. We calculated economic, social and environmental indicators. We interpret and discuss the scenario analysis in order to support the bioenergy planning under the light of its implications for the different policy aims and concerns.     

A bottom-up assessment and review of global bio-energy potentials to 2050

In this article, a model for estimating bioenergy production potentials in 2050, called the Quickscan model, is presented. In addition, a review of existing studies is carried out, using results from the Quickscan model as a starting point. The Quickscan model uses a bottom-up approach and its development is based on an evaluation of data and studies on relevant factors such as population growth, per capita food consumption and the efficiency of food production. Three types of biomass energy sources are included: dedicated bioenergy crops, agricultural and forestry residues and waste, and forest growth. The bioenergy potential in a region is limited by various factors, such as the demand for food, industrial roundwood, traditional woodfuel, and the need to maintain existing forests for the protection of biodiversity. Special attention is given to the technical potential to reduce the area of land needed for food production by increasing the efficiency of food production. Thus, only the surplus area of agricultural land is included as a source for bioenergy crop production. A reference scenario was composed to analyze the demand for food. Four levels of advancement of agricultural technology in the year 2050 were assumed that vary with respect to the efficiency of food production. Results indicated that the application of very efficient agricultural systems combined with the geographic optimization of land use patterns could reduce the area of land needed to cover the global food demand in 2050 by as much as 72% of the present area. A key factor was the area of land suitable for crop production, but that is presently used for permanent grazing. Another key factor is the efficiency of the production of animal products. The bioenergy potential on surplus agricultural land (i.e. land not needed for the production of food and feed) equaled 215–1272 EJ yr⁻¹, depending on the level of advancement of agricultural technology. The bulk of this potential is found in South America and Caribbean (47–221 EJ yr⁻¹), sub-Saharan Africa (31–317 EJ yr⁻¹) and the C.I.S. and Baltic States (45–199 EJ yr⁻¹). Also Oceania and North America had considerable potentials: 20–174 and 38–102 EJ yr⁻¹, respectively. However, realization of these (technical) potentials requires significant increases in the efficiency of food production, whereby the most robust potential is found in the C.I.S. and Baltic States and East Europe. Existing scenario studies indicated that such increases in productivity may be unrealistically high, although these studies generally excluded the impact of large scale bioenergy crop production. The global potential of bioenergy production from agricultural and forestry residues and wastes was calculated to be 76–96 EJ yr⁻¹ in the year 2050. The potential of bioenergy production from surplus forest growth (forest growth not required for the production of industrial roundwood and traditional woodfuel) was calculated to be 74 EJ yr⁻¹ in the year 2050.     

Multi Criteria Analysis for bioenergy systems assessments

Sustainable bioenergy systems are, by definition, embedded in social, economic, and environmental contexts and depend on support of many stakeholders with different perspectives. The resulting complexity constitutes a major barrier to the implementation of bioenergy projects. The goal of this paper is to evaluate the potential of Multi Criteria Analysis (MCA) to facilitate the design and implementation of sustainable bioenergy projects. Four MCA tools (Super Decisions, DecideIT, Decision Lab, NAIADE) are reviewed for their suitability to assess sustainability of bioenergy systems with a special focus on multi-stakeholder inclusion. The MCA tools are applied using data from a multi-stakeholder bioenergy case study in Uganda. Although contributing to only a part of a comprehensive decision process, MCA can assist in overcoming implementation barriers by (i) structuring the problem, (ii) assisting in the identification of the least robust and/or most uncertain components in bioenergy systems and (iii) integrating stakeholders into the decision process. Applying the four MCA tools to a Ugandan case study resulted in a large variability in outcomes. However, social criteria were consistently identified by all tools as being decisive in making a bioelectricity project viable.     

Land use change to bioenergy: A meta-analysis of soil carbon and GHG emissions

A systematic review and meta-analysis were used to assess the current state of knowledge and quantify the effects of land use change (LUC) to second generation (2G), non-food bioenergy crops on soil organic carbon (SOC) and greenhouse gas (GHG) emissions of relevance to temperate zone agriculture. Following analysis from 138 original studies, transitions from arable to short rotation coppice (SRC, poplar or willow) or perennial grasses (mostly Miscanthus or switchgrass) resulted in increased SOC (+5.0 ± 7.8% and +25.7 ± 6.7% respectively). Transitions from grassland to SRC were broadly neutral (+3.7 ± 14.6%), whilst grassland to perennial grass transitions and forest to SRC both showed a decrease in SOC (−10.9 ± 4.3% and −11.4 ± 23.4% respectively). There were insufficient paired data to conduct a strict meta-analysis for GHG emissions but summary figures of general trends in GHGs from 188 original studies revealed increased and decreased soil CO₂ emissions following transition from forests and arable to perennial grasses. We demonstrate that significant knowledge gaps exist surrounding the effects of land use change to bioenergy on greenhouse gas balance, particularly for CH₄. There is also large uncertainty in quantifying transitions from grasslands and transitions to short rotation forestry. A striking finding of this review is the lack of empirical studies that are available to validate modelled data. Given that models are extensively use in the development of bioenergy LCA and sustainability criteria, this is an area where further long-term data sets are required.     

Developing a sustainability framework for the assessment of bioenergy systems

The potential for biomass to contribute to energy supply in a low-carbon economy is well recognised. However, for the sector to contribute fully to sustainable development in the UK, specific exploitation routes must meet the three sets of criteria usually recognised as representing the tests for sustainability: economic viability in the market and fiscal framework within which the supply chain operates; environmental performance, including, but not limited to, low carbon dioxide emissions over the complete fuel cycle; and social acceptability, with the benefits of using biomass recognised as outweighing any negative social impacts. This paper describes an approach to developing a methodology to establish a sustainability framework for the assessment of bioenergy systems to provide practical advice for policy makers, planners and the bioenergy industry, and thus to support policy development and bioenergy deployment at different scales. The approach uses multi-criteria decision analysis (MCDA) and decision-conferencing, to explore how such a process is able to integrate and reconcile the interests and concerns of diverse stakeholder groups.     

The limits of modelling. Experiences with bioenergy in practice — could models have predicted this outcome?

Factors that complicate bioenergy model building are presented and discussed. Important aspects of ‘real-life’ energy systems that are difficult to represent in modelling are: the cost structure of energy production, information asymmetry, socioeconomic factors, household economics, strategic considerations, and policy uncertainties. The modeller can employ different strategies in dealing with these problems. Complicating aspects can be quantified and integrated in the model, mentioned when the implications of the model are discussed or they may merit separate quantitative or qualitative investigations. The authors make some recommendations as to how these aspects could be considered in the modelling work to improve model accuracy.     

Growing trade of bioenergy in the EU: Public acceptability, policy harmonization, European standards and certification needs

Since 2000, the consumption of bioenergy in the European Union has grown, along with a concurrent growth in the trade of biomass for energy purposes (though traded volumes still remain small). Bioenergy production and trade will likely continue to increase into the future, driven by climate change concerns, emissions reduction targets, increasing concerns about domestic energy security and favourable policies. The harmonization of European standards and the development of certification systems are key issues to resolving potential negative effects of increased biomass trade. Certification systems not only address the issue of environmental sustainability from production to end-use, but also allow for product differentiation while adding value to sustainably produced products, which can ultimately enhance a competitive and sustainable bioenergy market. In addition to analyzing bioenergy trade growth in the European Union, a questionnaire survey of 92 bioenergy experts from eight member states within the European Union was conducted. Survey results show that bioenergy is highly accepted in the European Union but that there is a lack of European standards and policy harmonization, along with the absence of a competitive market or a certification system, all of which are necessary for sustainable production and trade of bioenergy. A large majority (63 percent) of the total respondents agreed that the certification of bioenergy is necessary to promote the sustainable use of biomass.     

The effects of policy incentives in the adoption of willow short rotation coppice for bioenergy in Sweden

The effect of policy incentives in the development of short rotation willow plantations for bioenergy is studied by using an aggregate adoption model based on sigmoidal curves for the Swedish municipalities. A total of 56 municipalities were studied, with 891 farmers that planted willow during the period 1986–1996. The model included variables related to the subsidies applied, the taxation on fossil fuels, the development of the wood-fuel consumption by the district heating systems, and the geographical and socio-economic characteristics of the municipality. Results of the simulations using the model show an increment of almost 70% of farmers planting willow during the period studied when the subsidy and tax incentives and the increments of the wood-fuel capacity by the district heating system took place. This study gives tools for future policy implementations in order to achieve the goals of the energy strategies.     

Global bioenergy potentials from agricultural land in 2050: Sensitivity to climate change, diets and yields

There is a growing recognition that the interrelations between agriculture, food, bioenergy, and climate change have to be better understood in order to derive more realistic estimates of future bioenergy potentials. This article estimates global bioenergy potentials in the year 2050, following a "food first" approach. It presents integrated food, livestock, agriculture, and bioenergy scenarios for the year 2050 based on a consistent representation of FAO projections of future agricultural development in a global biomass balance model. The model discerns 11 regions, 10 crop aggregates, 2 livestock aggregates, and 10 food aggregates. It incorporates detailed accounts of land use, global net primary production (NPP) and its human appropriation as well as socioeconomic biomass flow balances for the year 2000 that are modified according to a set of scenario assumptions to derive the biomass potential for 2050. We calculate the amount of biomass required to feed humans and livestock, considering losses between biomass supply and provision of final products. Based on this biomass balance as well as on global land-use data, we evaluate the potential to grow bioenergy crops and estimate the residue potentials from cropland (forestry is outside the scope of this study). We assess the sensitivity of the biomass potential to assumptions on diets, agricultural yields, cropland expansion and climate change. We use the dynamic global vegetation model LPJmL to evaluate possible impacts of changes in temperature, precipitation, and elevated CO(2) on agricultural yields. We find that the gross (primary) bioenergy potential ranges from 64 to 161?EJ?y(-1), depending on climate impact, yields and diet, while the dependency on cropland expansion is weak. We conclude that food requirements for a growing world population, in particular feed required for livestock, strongly influence bioenergy potentials, and that integrated approaches are needed to optimize food and bioenergy supply.