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The use of biomass to produce biofuels can lead to both direct and indirect Land Use Change (LUC). While the causes underlying LUCs are complex their quantification is a scientific challenge that hinders decision-making. Here we demonstrate the application of participatory modelling in combination with System Dynamics techniques to the analysis of the land-change dynamics associated with biofuel supply chains. The ambition is to provide decision-makers with useful and credible knowledge of direct and indirect LUCs. We illustrate the application of the approach by applying it to a real‐world project for the production of advanced biofuels in Sardinia (Italy). The results show that the land use displacements vary in intensity and persistence depending on the crop management regime applied and the future development of the market of sheep cheese. The results were considered credible by actors with direct knowledge of the ‘real’ system and useful by decision makers .

Curbing aviation emissions is clear goal for the aviation sector, but it is a challenging task. At international level, the ICAO CORSIA initiative promotes the use of alternative fuels as a means to decarbonise flights. Among alternative fuels, lower carbon aviation fuels (LCAF) have been proposed under CORSIA. LCAF refers to a fossil fuel, which have been produced in a way that results in at least 10% lower lifecycle GHG emissions compared to a benchmark value. This paper analyses potential LCAF solutions for reducing GHG emissions of kerosene production and evaluates them relative to the ICAO baseline of 89.0 gCO2eq/MJ of fuel. The study analyses the levers that can reduce GHG upstream emissions (emissions from crude oil production) and refining emissions as well. This study shows that no one lever can reduce emissions to a sufficient level to meet the requirement of being a CORSIA-eligible fuel, and therefore that the deployment of multiple levers needed. Since jet fuel comprises only around 10% of total refining output, the LCAF measures could support the implementation of large, high-abatement cost changes, such as refinery-wide carbon capture and storage that affects multiple fuels.

Aviation fuel demand is expected to continue to grow over the next decades and continue to rely heavily on kerosene fuel for use in jet engines. While efficiency and operational improvements are possible ways to reduce GHG emissions, decarbonisation will need to heavily rely on low carbon kerosene drop-in alternatives. Currently, alternative fuels make up a very small share of fuel used in aviation, but their commercialisation is making good progress. Hydrogen offers a longer term alternative fuel option but requires aircraft design and fuelling infrastructure changes. Electrification is emerging as an option for providing propulsion in aircraft, either in pure form in small aircraft or in hybrid mode in larger aircraft. This paper reviews the status, challenges and prospects of alternative fuels and electrification in aviation.

E4tech conducted an important study (in 2018) for the Dutch Biofuels Platform and the Port of Rotterdam, as part of the development of a roadmap for decarbonising shipping in the Netherlands. In particular, biofuels can provide large reductions in GHG and non-GHG emissions, with a range of solutions for decarbonisation in the short and longer term. They offer greater decarbonisation potential compared to fossil alternatives aimed at tackling air quality emissions (e.g. LNG). The biofuels analysed were hydro-treated vegetable oil (HVO – including from waste oils and fats), Fatty acid methyl ester (FAME), straight vegetable oil (SVO), ethanol (both conventional and advanced production processes), bio-methanol, bio-LNG, Fischer-Tropsch diesel (FT-diesel) and Upgraded Pyrolysis Oil (UPO). The study determined the most attractive biofuel options based on criteria such as GHG reduction potential, readiness of production, cost and compatibility with the current vessel fleet in each shipping sub-sector: deep-sea, short-sea and inland shipping. It also provided recommendation on coordinated interventions from the range of actors in shipping industry that can support the uptake of biofuels, overcoming a range of technical, economic and operational barriers to their use.

The international aviation industry expects aviation biofuels to make a substantial contribution to reducing the sector’s CO2 emissions by 2050. This paper provides an analysis of the potential supply of sustainable aviation fuels globally and an insight into the contribution they could and would need to make towards carbon neutral growth of the aviation industry post 2020. It does so by developing scenarios of how much sustainable aviation fuel may be produced globally to 2030, and the resulting CO2 emissions savings. It then estimates the volume of sustainable fuel required to meet the aviation industry’s fuel-related CO2 emissions savings projections for 2050 and discusses the viability of such ambition.

The paper presents a mixed integer linear programming (MILP) approach to optimize multi-biomass and natural gas supply chain strategic design for heat and power generation in urban areas. The focus is on spatial and temporal allocation of biomass supply, storage, processing, transport and energy conversion (heat and CHP) to match the heat demand of residential end users. The main aim lies on the representation of the relationships between the biomass processing and biofuel energy conversion steps, and on the trade-offs between centralized district heating plants and local heat generation systems. After a description of state of the art and research trends in urban energy systems and bioenergy modelling, an application of the methodology to a generic case study is proposed. With the assumed techno-economic parameters, biomass based thermal energy generation results competitive with natural gas, while district heating network results the main option for urban areas with high thermal energy demand density. Potential further applications of this model are also described, together with main barriers for development of bioenergy routes for urban areas.

The paper presents the application of a mixed integer linear programming (MILP) methodology to optimize multi-biomass and natural gas supply chain strategic design for heat and power generation in urban areas. The focus is on spatial and temporal allocation of biomass supply, storage, processing, transport and energy conversion (heat and CHP) to match the heat demand of residential end users. The main aim lies on the assessment of the trade-offs between centralized district heating plants and local heat generation systems, and on the decoupling of the biomass processing and biofuel energy conversion steps. After a brief description of the methodology, which is presented in detail in Part I of the research, an application to a generic urban area is proposed. Moreover, the influence of energy demand typologies (urban areas energy density, heat consumption patterns, buildings energy efficiency levels, baseline energy costs and available infrastructures) and specific constraints of urban areas (transport logistics, air emission levels, space availability) on the selection of optimal bioenergy pathways for heat and power is assessed, by means of sensitivity analysis. On the basis of these results, broad considerations about the key factors influencing the use of bioenergy into urban energy systems are proposed. Potential further applications of this model are also described, together with main barriers for development of bioenergy routes for urban areas.

This paper describes ESCO approaches and business models for biomass heating and CHP generation. State of the art, policy measures and main barriers towards the implementation of such ESCO operations in Italy are discussed. Moreover, on the basis of the proposed framework, representative case studies in the Italian residential, tertiary and industrial market segments are compared. The case studies are referred to a 6 MWt wood chips fired plant. The case study of the industrial sector is based on a constant heat demand of a dairy firm, while in the tertiary and residential sectors the options to serve a concentrated heat demand (hospital) and a community housing by a district heating network are explored. The further option of coupling an organic Rankine cycle (ORC) for CHP is explored. The relevance of the research relies on the assessment of the main key factors towards the development of biomass-ESCO operations. The results of the techno-economic assessment show that the agro-industrial case study for heat generation is extremely profitable, because of the high baseline energy cost, the high load rate, the availability of incentives for biomass heating. The cogeneration option is also profitable, even if the higher investment cost determines a longer pay back time. The tertiary sector case study is also a profitable, for the presence of a concentrated load with high heat load rate and high energy cost. Finally, the residential sector case study is the least profitable, for the high district heating cost and the lower heat load rate, not compensated by the higher heat selling price. The higher investment cost of CHP, even if attracting further income from electricity sale, does not present higher profitability than the only heat generation plant. In addition, the heat load rate results a more influencing factor than the thermal energy selling price.

The production of next-generation biofuels both in the EU-27 and the USA involves producing biofuels beyond the conventional sugar, starch, vegetable oils, and animal-fat-based biofuels now produced commercially. Next-generation biofuels can be derived from non-food crops or agricultural residues, fast-growing trees, forestry, and municipal wastes, etc., and include (cellulosic) ethanol, butanol, methanol, dimethyl ether (DME), Fischer-Tropsch diesel, upgraded pyrolysis oils, microbial drop-in gasoline and diesel substitutes, and biofuels made from microbial oils and algae. The context of policy development for next-generation biofuels both in the USA and the EU-27 is based on the evidence that as demand for biofuels is growing and both the market and policies become more ambitious, a broader variety of feedstocks are needed to meet increasing production and use goals. At the moment, in both regions, policies to support conventional biofuels are still in place, but new strategies are being adopted at a fast rate to build a bridge from first-generation to next-generation biofuels and ensure sustainable supply. This paper presents the background and rationale for the current policy regimes and funding schemes in the USA and EU-27 in relation to next-generation biofuels, gives an update of the current market developments and provides a set of recommendations on the key issues that future policy formation should take into account to efficiently translate the ‘ambitious’ targets into a commercialization prospects. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd

Since early 2000, several biomass assessment studies were delivered at European and global level mostly driven by the increasing demand for the development of bioenergy and biofuels, and the need to secure sustainable, continuous supply for the emerging plants. Ongoing research and development and industrial development plus increased drivers to use renewable raw materials in industrial sectors beyond energy have seen the focus of the biomass markets widen to include value chains for bio-based chemicals, pharmaceuticals, and other materials. Consequently, research is now exploring increasingly varied configurations of value chains with the aims of understanding which types and quantifying how much biomass can be extracted sustainably, generate financial returns, and help the industry achieving high-quality products for consumers. This chapter sets the scene for research on biomass supply assessments in Europe and reviews 40 studies delivered during the last 14 years. It analyzes context, key components in terms of terminology, framework conditions and assumptions, models used, and evidence provided so far for policy, research, and industry. It further discusses the main challenges, identifies gaps, and provides recommendations.

Energy modelling that quantifies the costs and benefits of alternative energy strategies and implementation options has long held a central role in energy policy. Among others, MARKAL is a technology focused dynamic cost optimisation model, which contributed to numerous and wide-ranging energy policy studies, as well as to academic analysis of key energy policy and technology diffusion studies. This paper aims to review the representation of bioenergy chains in the current UK-MARKAL model up to 2050, and to propose some key improvements to be undertaken. The review is undertaken module by module, following the structure of the model, and the findings are listed with possible improvements suggested for bioenergy pathways.The improvements proposed to the UK-MARKAL model are wide-ranging, in line with the complexity of more credible bioenergy systems. They notably cover aspects such as: infrastructure costs and logistics, information asymmetry, socioeconomic factors, household economics, learning curves, imported biomass externalities, biomass supply dynamics (costs vs quantity), and representation of the demand side appropriate to policy analysis. Therefore, the proposed focus on a small number of key changes to the representation of bioenergy chains / pathways allows for the generation of preliminary insights on the scenarios to be investigated and the additional updates needed.

Biomass from lignocellulosic energy crops can contribute to primary energy supply in the short term in heat and electricity applications and in the longer term in transport fuel applications. This paper estimates the optimal feedstock allocation of herbaceous and woody lignocellulosic energy crops for England and Wales based on empirical productivity models. Yield maps for Miscanthus, willow and poplar, constrained by climatic, soil and land use factors, are used to estimate the potential resource. An energy crop supply-cost curve is estimated based on the resource distribution and associated production costs. The spatial resource model is then used to inform the supply of biomass to geographically distributed demand centres, with co-firing plants used as an illustration. Finally, the potential contribution of energy crops to UK primary energy and renewable energy targets is discussed.

In 2003 the UK Government introduced the reduction of CO2 emissions as a core objective of domestic energy policy. This initiated a policy process intended to realise a major expansion in the supply and use of biomass in the UK. Evidence of an expansion in the use of biomass is slight, and historically the UK has shown limited response to policy initiatives. This paper describes the policy context in the UK and EU, and presents a structured framework for analysing the policy debate including best practice criteria for policy formation. This framework is then used to assess whether the current debate is likely to affect the rate of implementation. We conclude that increased deployment will be driven by EU policy rather than domestic initiatives, and that the UK policy process falls short of best practice in that it fails to make a causal link between policy objectives and anticipated outcomes.

How large is the potential demand for bio-heat in the UK? Whilst most research has focused on the supply of biomass for energy production, an understanding of the potential demand is crucial to the uptake of heat from bioenergy. We have designed a systematic framework utilising market segmentation techniques to assess the potential demand for biomass heat in the UK. First, the heat market is divided into relevant segments, characterised in terms of their final energy consumption, technological and fuel supply options. Second, the key technical, economic and organisational factors that affect the uptake of bioenergy in each heat segment are identified, classified and then analysed to reveal which could be strong barriers, which could be surmounted easily, and for which bioenergy heat represents an improvement compared to alternatives. The defined framework is applied to the UK residential sector. We identify provisionally the most promising market segments for bioenergy heat, and their current levels of energy demand. We find that, depending on the assumptions, the present potential demand for bio-heat in the UK residential sector ranges between 3% (conservative estimate) and 31% (optimistic estimate) of the total energy consumed in the heat market.

This chapter describes a UK Sustainable Fuels Roadmap that was developed by the UK’s Sustainable Aviation (SA) Group in 2014. SA represents the main UK airlines, airports, manufacturers, and air navigation service providers, and works on a collective approach to tackle the challenge of ensuring a sustainable future for the aviation industry. The Roadmap assessed the potential for sustainable fuels to mitigate carbon dioxide (CO 2 ) emissions from UK aviation in the period up to 2050. The study concluded that with supportive policy mechanisms in place, sustainable fuels could reduce emissions from UK aviation by up to 24% in the period up to 2050. A UK-based sustainable fuels sector could provide up to 12 new production biorefineries in the UK by 2030 and the creation of a Gross Added Value to the UK economy of up to £265 m.

The major purpose of this book is to lay out the broad landscape of global energy issues and how they might develop in coming decades.

Climate change, air quality and energy security will change the way energy is used and supplied over the next century. Supplying increasing amounts of clean and secure energy will be a challenge that will require a great deal of innovation and investment. However, this paper shows that there are visible paths to clean and secure energy. There are plenty of resource and technology options that could lead to emissions reductions in the heat, transport and electricity sector, while improving energy security. The costs of supplying energy from different options vary widely. However, several clean energy options are viable today and several others are likely to be so in the future, as technologies improve, costs are reduced, and the competitive landscape for energy technologies evolves. Tackling climate change and energy security requires the simultaneous deployment of available commercial clean technologies, demonstration and commercialisation of technologies at the advanced research, development and demonstration stage, and research into new technologies.

One of the principal barriers to the widespread use of hydrogen as a road transport fuel is the need for a refuelling infrastructure to be established. The lack of an adequate refuelling infrastructure would severely inhibit an uptake of hydrogen vehicles. On the other hand, without significant penetration of these vehicles, the demand for hydrogen would be insufficient to make a widespread conventional refuelling infrastructure economic. The infrastructure is likely to develop initially in cities, due to the high concentration of vehicles and the anticipated air quality benefits of a switch to hydrogen as a road transport fuel. While trial schemes such as the Clean Urban Transport for Europe (CUTE) bus project will establish initial hydrogen refuelling sites, it is not clear how a transition to a widespread refuelling infrastructure will occur. Indeed, the number of possible different ways and scales of producing and distributing hydrogen means that the possible configurations for such an infrastructure are almost endless. Imperial College London is examining transition strategies for a hydrogen infrastructure for vehicle refuelling in London under a project funded by the UK Engineering and Physical Sciences Research Council (EPSRC). Imperial has five project partners from industry and local government to assist in this study: the Greater London Authority (GLA), BP, BOC, BMW and Air Products. This paper presents initial results from technical modelling of hydrogen infrastructure technologies and how they could be deployed to provide an initial facility for the refuelling of hydrogen fuel-cell buses in London. The results suggest that the choice of H2 production technology can have significant effects on when the infrastructure would be installed, and the timing of hydrogen production, and bus refuelling.

Increasing demand for power and the depletion of fossil fuels are providing opportunities for the development of fuel cells as power generating systems. This paper investigates the integration of a solid oxide fuel cell (SOFC) with biomass gasification for the production of power and heat (combined heat and power (CHP) system). A steady-state model was developed in the gPROMS modelling tool to investigate the integrated system. The system was modelled for two different options, a cold process involving gas cleaning at a reduced temperature and a hot process involving gas cleaning at a high temperature. For each option, the model was used to determine the system efficiency and prospective costs. The electrical efficiency and overall system efficiency for the hot process were found to be 23 and 60% and for the cold process the efficiencies were 21 and 34%, respectively. Superior heat management in the gas cleaning stage of the hot process results in its higher system efficiency. The capital cost for the hot process appears higher than that for the cold process. This differential capital cost may be justified by the income earned from selling the extra heat produced in the hot process. Conversely, the cold process produces a gas stream with lower levels of impurities than the hot process.

Fuel cells are still in development as power generation technologies. They are potentially efficient and low-emissions power generation technologies with a wide range of applications. Their deployment world wide and in developing countries in particular could result in mitigation of future greenhouse gas emissions and possibly other environmental and social benefits. The economics of the systems and their competitiveness with other power generation systems will be heavily dependent on local costs and infrastructure. Modelling, based energy demand projection and on fuel cell demand curves derived from expert interviews, suggests that worldwide, projected future cost reductions in fuel cells could result in fuel cell penetration of up to 50% of the world distributed generation market by 2020. This penetration, coupled with the use of a mix of low-carbon fuels, such as natural gas, would result in significant avoided emissions of CO2 over the same period. Also, a comparison of the levelised costs of generation for the Philippines and South Africa suggests that some fuel cell technologies could become competitive with centralised generation within the next decade. Assuming that fuel cell durability can be demonstrated, the potential for fuel cells to be introduced into distributed generation in certain developing countries appears high, from a technical, economic and environmental perspective.

Hydrogen fuel cell vehicle (H 2 FCV) trials are taking place in a number of cities around the world. In Italy, Milan and Turin are the first to have demonstration projects involving hydrogen-fuelled vehicles, in part to satisfy increasing consumer demand for improved environmental performance. The Italian transport plan specifically highlights the potential for FCVs to enter into the marketplace from around 2005. A scenario for FCV penetration into Italy, developed using projected costs for FCV and hydrogen fuel, suggests that by 2015, 2 million Italian cars could be powered by fuel cells. By 2030, 60% of the parc could be FCVs. To develop an infrastructure to supply these vehicles, a variety of options is considered. Large-scale steam reforming, on-site reforming and electrolysis options are analysed, with hydrogen delivered both in liquid and gaseous form. Assuming mature technologies, with over 10,000 units produced, on-site steam reforming provides the most economic hydrogen supply to the consumer, at US$ 2.6/kg. However, in the early stages of the infrastructure development there is a clear opportunity for on-site electrolysis and for production of hydrogen at centralised facilities, with delivery in the form of liquid hydrogen. This enables additional flexibility, as the hydrogen may also be used for fuel refining or for local power generation. In the current Italian context, energy companies could have a significant role to play in developing a hydrogen infrastructure. The use of hydrogen FCVs can substantially reduce emissions of regulated pollutants and greenhouse gases. Using externality costs for regulated pollutants, it is estimated that the use of hydrogen fuel cell buses in place of 5% of diesel buses in Milan could avoid US$ 2 million per year in health costs. The addition of even very low externality costs to fuel prices makes the use of untaxed hydrogen in buses and cars, which is slightly more expensive for the motorist than untaxed gasoline or diesel, competitive on a social cost basis.

Using an open-frame helium-neon (He-Ne) laser and optical spectrum analyser, students performed several upper-division laboratory experiments investigating important concepts regarding laser fundamentals. Such experiments include cavity stability (mirror geometry and thermal effects), longitudinal and transverse modes, free spectral range, and mode sweeping. In this paper we discuss, in an elementary way, the experimental procedures and results obtained.

The paper describes results of the BioCosts project in which a comprehensive analysis of the economic and environmental performance of the energy use of biomass was carried out for selected existing facilities throughout the European Union. It is demonstrated that the appropriately organized use of biofuels has significant environmental advantages compared to the use of fossil fuels. Mitigation of global warming is the largest single incentive to use biofuels. However, only a few technologies are economically competitive under prevailing conditions, while others lead to up to 100% higher energy production costs than fossil fuels. Employment effects of using biofuels are small but positive. http://www.sciencedirect.com/science/article/B6V2S-41JM99D-4/1/514a3253589af4590f84544e2966bcb3

The possibility that future solid polymer fuel cell vehicles will be fuelled by methanol has been suggested. If this is the case, it will have significant implications for the future structure of the methanol supply industry, and methanol supply and availability may have an impact on the take-up of these SPFC vehicles. In this study, a model assessing the possible future penetration of methanol SPFC vehicles was constructed. This suggested that it would be possible for SPFC vehicles to achieve rapid market penetration after an initially slow start. A further model indicated that methanol supply would be adequate for vehicle demand until about 2013, when significant new capacity would be required. The cost of this new capacity was estimated, along with the cost of providing refuelling infrastructure such as road tankers, storage, and suitable fuelling stations. Amortising the cost over a short period (to 2013) could double the pre-tax price of methanol as a fuel, while over a longer timeframe (to 2029) it would add less than 10% to this value. The model suggests that methanol capacity need not be a constraint to the future introduction of SPFC vehicles using it as a fuel, but that other factors such as fuel purity and safety must be carefully considered before real costs can be calculated.

Fuel cells (FCs) offer significant environmental benefits over competing technologies and hence the environment is a strong driving force behind the development of FC systems for transport and stationary applications. This paper provides a comprehensive comparison of FC and competing systems, and points out strengths and weaknesses of the different FC systems, suggesting areas for improvement. The results presented build on earlier work [D. Hart, G. Hormandinger, Initial assessment of the environmental characteristics of fuel cells and competing technologies, ETSU F/02/00111/REP/1, ETSU, Harwell, UK, 1997.] and provide a detailed analysis of a wider range of systems. The analysis takes the form of a model, which compares system emissions (global, regional and local pollutants) and energy consumption on a full fuel cycle basis. It considers a variety of primary energy sources, intermediate fuel supply steps and FC systems for transport and stationary end-uses. These are compared with alternative systems for transport and stationary applications. Energy and pollutant emission reductions of FC systems compared to alternative vehicle technology vary considerably, though all FC technologies show reductions in energy use and CO2 emissions of at least 20%; as well as reductions of several orders of magnitude in regulated pollutants compared to the base-case vehicle. The location of emissions is also of importance, with most emissions in the case of FC vehicles occurring in the fuel supply stage. The energy, CO2 and regulated emissions advantages of FC systems for distributed and baseload electricity are more consistent than for transport applications, with reductions in regulated pollutants generally larger than one order of magnitude compared to competing technologies. For CHP applications, the advantages of FC systems with regard to regulated pollutants remain large. However, energy and CO2 emission advantages are reduced, depending largely on the assumptions made for the heat/power ratio and system comparison.

Mechanisation of sugarcane harvesting is growing rapidly in Southern Brazil where nearly 80% of Brazil’s crop is cultivated. Currently a maximum of 20% of the cane is mechanically harvested and the proportion is expected to rise to about 50% by 2005. However, most of the cane is burned prior to harvesting and less than 2% is harvested green. Issues such as topography, crop cultivation and management methods, labour costs, machine performance, environmental legislation and markets for sugarcane residues will influence the increase in mechanical harvesting of burned or green cane. This paper discusses the prospects for green cane harvesting technology, with emphasis on Southern Brazil, and compares harvesting technologies which are being commercialised today. The paper also addresses the recovery of cane residues (dry and green tops and leaves) and comments on their possible use and commercialisation, particularly for electricity generation.

This paper discusses the performance characteristics of a 280 kWth fluidized bed gasifier fueled with bagasse pellets. The gasifier was designed by the State University of Campinas (UNICAMP) and built by TERMOQUIP Energia Alternativa Ltda, based in Campinas, Brazil. Preliminary tests were performed in 1996 to determine the reactor performance as part of the gasification pilot plant test programme. A series of parameters, such as the lower heating value, heat losses, cold and hot gas thermal efficiency and gas yield, were measured as a function of the gasification air factor.

Externalities of electricity production from biomass and coal are investigated and compared for the Dutch context. Effects on economic activity and employment are investigated with help of input/output and multiplier tables. Valuations of damage from emissions to air are based on generic data from other studies. In addition external costs are estimated for nitrogen leaching and for the use of agrochemicals for energy crop production. The average private costs for biomass and coal based power generation are projected to be 68 and 38 mECU/kWh, respectively in the year 2005. It is assumed that biomass production takes place on fallow land. Coal mining is excluded from the analysis. If the quantified external damages and benefits are included the cost range for bio-electricity is 53–70 mECU/kWh and 45–72 mECU/kWh for coal. Indirect economic effects (increment of gross domestic product) and the difference in CO 2 emissions are the most important distinguishing factors between coal and biomass in economic terms. Damage costs of other emissions to air (NO x , SO 2 , dust and CO) are of the same order of magnitude for both coal and biomass (coal mining excluded). In this analysis environmental impacts of energy farming are compared mainly with fallow land focused on the use of fertilisers and agrochemicals. The related damage costs appear to be low but should be considered as a preliminary estimate only. The quantitative outcomes should not be considered as the external costs of the two fuel cycles studied. Many impacts have not been valued and large uncertainties persist, e.g. with respect to the costs of climate change and numerous dose–response relations. More detailed analysis is desired with respect to macro-economic impacts. The results serve as a first indication, but the outcomes plead for the support of bio-electricity production and/or taxation of coal-based power generation.

This study develops a modelling framework within which the effects of technology choice and policy on the sustainability of cities may be assessed. A life cycle accounting system for environmental impacts is combined with systems analysis, to represent the flows of resources into cities, the wastes and pollution generated and the technological choices available in an urban environment. The approach is demonstrated through a case study of the demand for paper and management of wastepaper. The case study questions the applicability for paper of the accepted 'hierarchy' of waste management techniques; incineration imposes lower environmental costs than recycling, and consequently lower total costs under some circumstances.

Previous controlled studies have shown that preventive home visits are a promising method for disability prevention in elderly persons; however, due to the lack of data on cost effectiveness and optimal intervention methods, there is still debate on their usefulness. Therefore, additional controlled studies must use new methods to resolve these unanswered issues. We present a novel approach used in the project EIGER (Evaluation of In-Home Geriatric Health Visits in Elderly Residents), an ongoing randomized controlled trial of preventive home visits in community-residing persons aged 75 years and older in Bern, Switzerland. The intervention consists of inhome visits with structured comprehensive geriatric assessment and follow-up by specially trained nurses who collaborate with geriatricians and an interdisciplinary team. Special methods were used to optimize the sample size, to improve the health care cost analysis, to minimize and explore refusal to participate, to apply stratified randomization for subgroup analysis, and to evaluate the intervention process with a tracer method. Selected baseline findings (N=791, mean age 82 years, 73% female) include uncontrolled systolic hypertension (54%), balance/gait disorder (9%), cognitive impairment (7%), 6 or more medications (21%), depressive symptoms (10%), and impaired basic ADL (15%). Baseline findings demonstrate that this study is likely to contribute to some of the unresolved issues of in-home prevention for older persons. (Aging Clin. Exp. Res. 7: 218-223, 1995)

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Working Paper

Background Calculating the greenhouse gas savings that may be attributed to biofuels is problematic because production systems are inherently complex and methods used to quantify savings are subjective. Differing approaches and interpretations have fuelled a debate about the environmental merit of biofuels, and consequently about the level of policy support that can be justified. This paper estimates and compares emissions from plausible supply chains for lignocellulosic ethanol production, exemplified using data specific to the UK and Sweden. The common elements that give rise to the greatest greenhouse gas emissions are identified and the sensitivity of total emissions to variations in these elements is estimated. The implications of including consequential impacts including indirect land-use change, and the effects of selecting alternative allocation methods on the interpretation of results are discussed. Results We find that the most important factors affecting supply chain emissions are the emissions embodied in biomass production, the use of electricity in the conversion process and potentially consequential impacts: indirect land-use change and fertiliser replacement. The large quantity of electricity consumed during enzyme manufacture suggests that enzymatic conversion processes may give rise to greater greenhouse gas emissions than the dilute acid conversion process, even though the dilute acid process has a somewhat lower ethanol yield. Conclusion The lignocellulosic ethanol supply chains considered here all lead to greenhouse gas savings relative to gasoline An important caveat to this is that if lignocellulosic ethanol production uses feedstocks that lead to indirect land-use change, or other significant consequential impacts, the benefit may be greatly reduced. Co-locating ethanol, electricity generation and enzyme production in a single facility may improve performance, particularly if this allows the number of energy intensive steps in enzyme production to be reduced, or if other process synergies are available. If biofuels policy in the EU remains contingent on favourable environmental performance then the multi-scale nature of bioenergy supply chains presents a genuine challenge. Lignocellulosic ethanol holds promise for emission reductions, but maximising greenhouse gas savings will not only require efficient supply chain design but also a better understanding of the spatial and temporal factors which affect overall performance.

The cost effective production of transport fuels from biomass is essential if the EU aspiration to substitute 10% of transport fuels with sustainable alternatives by 2020 is to be met. The hope, voiced by the Parliament’s Industry and Energy Committee, is that at least 40% of the 2020 target will come from second-generation biofuels, and therein lies the challenge: second-generation conversion technologies are not yet commercial. Multiple pathways are being investigated around the globe, but dominant pathways have yet to emerge and business models have yet to be proven. Nevertheless, expectations are running high and there has been significant investment in R&D in the US, Europe and Asia. The production of ethanol from lignocellulosic biomass is commercially and environmentally one of the most promising options, and in 2007 the US Department of Energy (DOE) provided more than US$1 billion toward lignocellulosic ethanol (LE) projects. Their goal was to make the fuel cost competitive at $1.33 per gallon, when deployed at scale, by 2012. The majority of studies also suggest that LE will result in superior greenhouse gas savings compared to ethanol produced from starch. Despite favourable predictions for cost and environmental performance, market deployment requires practical and plausible development paths that are able to support progress from existing small-scale demonstration plant to large industrial installations. Moreover, these development paths must be sufficiently attractive to persuade developers and investors that lignocellulosic ethanol remains an opportunity worth pursuing.

Background The production of fuel-grade ethanol from lignocellulosic biomass resources has the potential to increase biofuel production capacity whilst minimising the negative environmental impacts. These benefits will only be realised if lignocellulosic ethanol production can compete on price with conventional fossil fuels and if it can be produced commercially at scale. This paper focuses on lignocellulosic ethanol production in Europe. The hypothesis is that the eventual cost of production will be determined not only by the performance of the conversion process but by the performance of the entire supply-chain from feedstock production to consumption. To test this, a model for supply-chain cost comparison is developed, the components of representative ethanol supply-chains are described, the factors that are most important in determining the cost and profitability of ethanol production are identified, and a detailed sensitivity analysis is conducted. Results The most important cost determinants are the cost of feedstocks, primarily determined by location and existing markets, and the value obtained for ethanol, primarily determined by the oil price and policy incentives. Both of these factors are highly uncertain. The best performing chains (ethanol produced from softwood and sold as a low percentage blend with gasoline) could ultimately be cost competitive with gasoline without requiring subsidy, but production from straw would generally be less competitive. Conclusion Supply-chain design will play a critical role in determining commercial viability. The importance of feedstock supply highlights the need for location-specific assessments of feedstock availability and price. Similarly, the role of subsidies and policy incentives in creating and sustaining the ethanol market highlights the importance of political engagement and the need to include political risks in investment appraisal. For the supply-chains described here, and with the cost and market parameters selected, selling ethanol as a low percentage blend with gasoline will maximise ethanol revenues and minimise the need for subsidies. It follows, therefore, that the market for low percentage blends should be saturated before markets for high percentage blends.

This paper provides an overview of some of the key technological and market developments for leading renewable energy technologies—wind, wave and tidal, photovoltaics (PV) and biomass energy. Market growth, innovation and policy are closely interrelated in the development of renewables and the key issues in each area are explored for each of the main types of renewable energy technology. This enables the prospects for future development and cost reduction to be considered in detail. Key issues for policy are outlined. Keywords: Renewable energy, Technological development, Market growth

Sugarcane residues, in the form of bagasse and cane tops and leaves, represent a large renewable biomass energy resource in Brazil. Bagasse is currently used to satisfy the energy needs of the sugar and alcohol industry with poor efficiency and poor environmental control. Advanced conversion technologies, such as biomass integrated gasification combined cycles (BIG/CC), can lead to high conversion efficiencies and significant improvements in environmental performance. The use of cane tops and leaves, in addition to bagasse, could add significantly to the energy produced. There is then a large potential for sugarcane mills to act as economically viable decentralised power plants selling electricity to the grid. Furthermore, the power produced may present important environmental benefits compared to conventional alternatives.

There are large opportunities for the operation of fuel cells with renewable fuels in isolated and island communities. Hydrogen can be produced from the electrolysis of water using solar, wind and hydro electricity, while other fuels can be produced from the thermo-chemical or biological decomposition of biomass and waste. These can be upgraded to hydrogen or cleaned and used directly in fuel cells. Renewable fuel cell-based energy can be used in stand-alone or grid connected applications. It can provide independent power or complement variable renewable energy sources. Also, it can improve the economic and environmental performance of renewable energy systems and provide significant environmental and often economic benefits over non-renewable alternatives.

Publisher Summary This chapter throws attention on the sustainable heat and electricity supply from gasification based biomass fuel cycles. The chapter provides an analysis of the economic and the environmental performance of BIG or CC systems based on two case studies fuelled with forestry residues in Sweden, and with short rotation coppice and forestry residues in the United Kingdom. The results show that heat and electricity from BIG or CC systems may represent an important future sustainable energy supply option. Biomass integrated gasification combined cycle systems are currently being demonstrated. Their market penetration depends on their technical viability, and economic and environmental performance, in particular compared to the conventional fossil-based fuel cycles. The use of biomass fuels can also result in other environmental and socio-economic benefits. Biomass use can alleviate acidification in Swedish forests, contribute to more sustainable agricultural practice, reduce the dependency and expenditure on imported fuels, and create employment in disfavored regions and sectors. Finally, BIG or CC systems hold promise as a sustainable energy supply option, based on biomass resource potential, projected cost reductions, and environmental and social benefits compared to the conventional energy sources.