Life-cycle assessment in the renewable energy sector

The Polish energy industry is facing challenges regarding energetic safety, competitiveness, improvement of domestic companies and environmental protection. Ecological guidelines concern the elimination of detrimental solutions, and effective energy management, which will form the basis for sustainable development. The Polish power industry is required to systematically increase the share of energy taken from renewable sources in the total energy sold to customers. Besides the economic issues, particular importance is assigned to environmental factors associated with the choice of energy source. That is where life-cycle assessment (LCA) is important. The main purpose of LCA is to identify the environmental impacts of goods and services during the whole life cycle of the product or service. Therefore LCA can be applied to assess the impact on the environment of electricity generation and will allow producers to make better decisions pertaining to environmental protection. The renewable energy sources analysed in this paper include the energy from photovoltaics, wind turbines and hydroelectric power. The goal and scope of the analysis comprise the assessment of environmental impacts of production of 1 GJ of energy from the sources mentioned above. The study will cover the construction, operation and waste disposal at each power plant. Analysis will cover the impact categories, where the environmental influence is the most significant, i.e. resource depletion, global warmth potential, acidification and eutrophication. The LCA results will be shown on the basis of European and Australian research. This analysis will be extended with a comparison between environmental impacts of energy from renewable and conventional sources. This report will conclude with an analysis of possibilities of application of the existing research results and LCA rules in the Polish energy industry with a focus on Poland's future accession to the European Union. Definitions of LCA fundamental concepts, its methodology and application are described in the ISO 14040-14049 series of standards. These standards have already been introduced in some countries, but in Poland they are still at the stage of translation into Polish. Nevertheless some companies in Poland try to assess how their products influence the environment and what are the possibilities of technology improvement in the existing production process reduce their environmental impact.     

Domestic solar thermal water heating: A sustainable option for the UK?

This paper considers life cycle environmental sustainability of solar water heating systems in regions with low solar irradiation, such as the UK. The results suggest that flat plate collectors have slightly lower environmental impacts than evacuated tube designs. Reducing the current energy losses of 65%–45% would reduce the impacts by around 35%. Compared to a gas boiler, solar thermal systems are a better option for only five out of 11 environmental impacts considered, with global warming and depletion of fossil resources being lower by 88% and 83%, respectively. Other impacts such as human and eco-toxicity are up to 85% higher. The solar systems score better relative to electrical water heating for eight out of 11 impacts. They are also environmentally more sustainable than heat pumps for seven categories. However, their potential is hampered because they need a back-up heating system, typically gas boiler. For this reason as well as due to a lack of suitable locations and poor efficiency, the potential of solar thermal systems to contribute to a more sustainable domestic energy supply in the UK is limited.     

燃生物质颗粒工业锅炉系统的生命周期评价

为了研究生物质工业锅炉系统对环境影响和能源消耗情况,本文采用了生命周期(LCA)的研究方法,从该系统的原料生产制作,到系统建立运行进行全面分析。结果表明:处理每1 t生物质颗粒,对环境的总影响负荷为16 434.47毫人当量,资源耗竭系数为2.547毫人当量,燃生物质工业锅炉系统对环境影响主要为全球变暖为95.36%,各个过程中锅炉系统运行影响为98.55%,秸秆种植从环境中吸收CO22 136.24 kg,因此,燃生物质工业锅炉系统在减少温室气体排放上能起积极作用,与燃煤锅炉相比生物质锅炉是一种环境友好并且减少化石燃料消耗的项目。     

Reformulating taxes for an energy transition

An energy transition toward clean energy sources would reduce environmental impacts. One proposal to trigger this energy transition uses economic instruments, particularly environmental taxes. This research studies the potential impact of taxes on electricity on the environment and the economy. Using a dynamic computable general equilibrium model for Spain with energy and environmental extensions, we assess their current impact on GDP growth, energy use, and a set of different pollutant emissions. Then we propose a reform that would foster an energy transition toward clean energies and assess their economic and environmental impact. We find that only taxing the production of electricity by coal, oil, and natural gas can be better for the environment and economy than taxing all forms of electricity production in a revenue-neutral context. Moreover, the production of electricity by biomass, though considered renewable, is an important source of pollutant emissions and, in these terms, should have less importance in an energy transition.     

Risks and financing decisions in the energy sector: An empirical investigation using firm-level data

Using a sample of 102 UK energy firms over the period 1981–2009, this paper empirically examines the effects of uncertainty on firms' leverage decisions. The results indicate that both firms-specific and macroeconomic uncertainty have negative, sizeable, and statistically significant impacts on the UK energy sector firms' target leverage. The results also indicate that the profitability of energy firms plays an important role in uncertainty–leverage relationship by changing the (total) effect of uncertainty on leverage. While more profitable firms appear to reduce their leverage by a relatively large amount in response to increased macroeconomic uncertainty, they are less likely to be affected by firm-specific uncertainty. These results suggest that stability in macroeconomic conditions and business activity is important to the stability of the capital structure of firms in the energy sector which would in turn be conducive to stability in their investments and production.     

Demand reduction in the UK—with a focus on the non-domestic sector

A demand reduction strategy is considered in the context of the UK and in the light of the UK Government's 2006 Energy Review. This paper discusses how a mechanism—a Demand Reduction Obligation (DRO)—can be established to achieve radical energy demand reduction targets in electricity and gas use in the industrial, commercial and public administration sectors. A DRO would require energy suppliers to invest in energy-saving measures so as to reduce energy demand in these sectors. The investment for this activity would be funded by energy suppliers who would increase prices in order to cover the cost of achieving the carbon reductions. Public opinion surveys suggest that a large proportion of the public would prefer to support demand reduction measures compared to other energy options. It may be practical to deliver carbon emission reductions equivalent to around 30% of emissions from the UK electricity sector over a 15-year period through a broad-based demand reduction strategy. Demand reduction is considered in the context of an assessment of costs and resources available from other low carbon options including renewable energy and nuclear power.     

Selected environmental impacts of the technical production of wood chips from poplar short rotation coppice on marginal land

The use of marginal land for Short Rotation Coppice (SRC) might contribute to a sustainable energy supply in future. We assessed the environmental impacts of common production chains for manufacturing wood chips from SRC with poplar, including all the processes necessary to produce and deliver chips to a plant gate in 50 km distance from the field site (“cradle-to-plant gate”).To do so, we carried out a Life Cycle Analysis (LCA) including upstream processes. Results showed clearly that the specific environmental impacts were mainly caused by the processes “harvesting” and “transport”. Using a cut-and-chip harvesting system with a forage harvester generated low impacts during harvesting because of its high productivity. Using a cut-and-storage harvesting system with a whole rod harvester, however, didn't require accompanying tractor-trailer units during harvesting and allowed storing stems before chipping thereby, reducing the moisture content to approximately 30%. Consequently, the transport to the plant caused significantly lower environmental impacts at the same distance (50 km) which lead to a better result when looking at the overall production chain (26 vs. 36 kg CO₂-eq Mg_dm⁻¹). Respective energy output to energy input ratios were 23:1 and 26:1.We also analysed the impacts of irrigation and fertigation as they might be options to increase biomass yield. Both treatments lead to considerably increased environmental impacts in all analysed categories which might be balanced only if the biomass yields increase substantially; an effect which could not be verified within the current study.     

Integrated policies for energy and the environment: Options for the UK in a World Context

A sustainable global strategy for energy and the environment should be based on two fundamental precepts: the effective harnessing of ambient energy (that originating from either incident insolation or gravitational forces between the Earth and the Moon); the employment of processes that ensure the harnessed energy is used efficiently, for example, via CHP plant or fuel cells, and in general through well designed and operated, and usually thermally insulated systems. If present trends persist, the world may experience by the middle of the twenty-first century severe difficulties in meeting from fossil fuels its requirements for energy. Thus the UK needs to avoid acting exclusively for the short term, and to devise and soon implement a long-term strategy for energy and environmental. This report identifies the constraints on British energy policy and assesses future prospects for various energy sources, including their environmental impacts.     

Life cycle impacts of waste wood biomass heating systems: A case study of three UK based systems

With increasing renewable energy targets and the use of biomass for energy production, questions arise about the sustainability of differing types of bioenergy. Much has been made about the renewable transport fuel obligations and the impact the production of biofuel can have on the environment, but there has been less consideration of more small scale biomass heating systems. This work examines the life cycle impacts of the production and use of three such systems using waste wood in the South West of England. Burning of wood in the UK was reduced after the introduction of legislation to reduce smog in the 1950s, and so the impact of the emissions from the boilers has been examined. Whilst the boilers studied complied with UK emissions legislation, the emissions were the most significant impact found. However, there were differences in the emission levels depending on the loading of the boiler. In all cases the energy payback of the systems was under one year, ranging from approximately four to ten months.     

The energy and environmental impacts of Italian households consumptions: An input–output approach

Promoting sustainable consumption and production patterns is a key challenge for the future, in order to use the Earth resources efficiently, to reduce the greenhouse gas emissions, and to decouple the economic growth from the environmental degradation.New or customized methods have to be applied to support decisions makers in the choice of environmental-friendly products, and to select policy priorities and sustainable strategies.A modified input–output model can aid to analyse the relationships among economic growth, energy consumptions and pollutants, in order to assess the energy and environmental impacts due to the actual production and consumption patterns.The following paper introduces an energy and environmental extended input–output model and combines it with the Life Cycle Assessment (LCA) methodology.The authors apply this model to the Italian context in order to assess the energy and environmental impacts related to the consumptions of the Italian households in the period 1999–2006 and to identify the economic sectors involving the highest impacts.The paper represents one of the first Italian studies aimed at identifying those national economic sectors and final goods and services to be assumed prior in the definition of sustainable production and consumption strategies. Results show that about the 70% of the total energy, needed to meet the household final demand of products, is consumed by the productive sectors. In particular tertiary, “electricity, gas and vapour”, road transports and “food and beverage” sectors are the most contributors, accounting for about 75%.Further, the environmental impact analysis associated to Italian households consumptions is carried out, starting from three different data sources The results point out that, to include emissions arising both from energy and non-energy sources, in the assessment of environmental impacts is of paramount importance to obtain reliable simulations of the link between households consumptions and energy and environmental performances.     

Life cycle assessment of geothermal binary power plants using enhanced low-temperature reservoirs

Geothermal binary power plants that use low-temperature heat sources have gained increasing interest in the recent years due to political efforts to reduce greenhouse gas emissions and the consumption of finite energy resources. The construction of such plants requires large amounts of energy and material. Hence, the question arises if geothermal binary power plants are also environmentally promising from a cradle-to-grave point of view. In this context, a comprehensive Life Cycle Analysis (LCA) on geothermal power production from EGS (enhanced geothermal systems) low-temperature reservoirs is performed. The results of the analysis show that the environmental impacts are very much influenced by the geological conditions that can be obtained at a specific site. At sites with (above-) average geological conditions, geothermal binary power generation can significantly contribute to more sustainable power supply. At sites with less favorable conditions, only certain plant designs can make up for the energy and material input to lock up the geothermal reservoir by the provided energy. The main aspects of environmentally sound plants are enhancement of the reservoir productivity, reliable design of the deep wells and an efficient utilization of the geothermal fluid for net power and district heat production.     

Optimal design of wind-powered hydrogen refuelling station for some selected cities of South Africa

The transport sector is considered as one of the sectors producing high carbon emissions worldwide due to the use of fossil fuels. Hydrogen is a non-toxic energy carrier that could serve as a good alternative to fossil fuels. The use of hydrogen vehicles could help reduce carbon emissions thereby cutting down on greenhouse gases and environmental pollution. This could largely be achieved when hydrogen is produced from renewable energy sources and is easily accessible through a widespread network of hydrogen refuelling stations. In this study, the techno-economic assessment was performed for a wind-powered hydrogen refuelling station in seven cities of South Africa. The aim is to determine the optimum configuration of a hydrogen refuelling station powered by wind energy resources for each of the cities as well as to determine their economic viability and carbon emission reduction capability. The stations were designed to cater for 25 hydrogen vehicles every day, each with a 5 kg tank capacity. The results show that a wind-powered hydrogen refuelling station is viable in South Africa with the cost of hydrogen production ranging from 6.34 $/kg to 8.97 $/kg. These costs are competitive when compared to other costs of hydrogen production around the world. The cities located in the coastal region of South Africa are more promising for siting wind powered-hydrogen refuelling station compared to the cities located on the mainland. The hydrogen refuelling stations could reduce the CO₂ and CO emissions by 73.95 tons and 0.133 tons per annum, respectively.     

Life cycle assessment of various cropping systems utilized for producing biofuels: Bioethanol and biodiesel

A life cycle assessment of different cropping systems emphasizing corn and soybean production was performed, assuming that biomass from the cropping systems is utilized for producing biofuels (i.e., ethanol and biodiesel). The functional unit is defined as 1 ha of arable land producing biomass for biofuels to compare the environmental performance of the different cropping systems. The external functions are allocated by introducing alternative product systems (the system expansion allocation approach). Nonrenewable energy consumption, global warming impact, acidification and eutrophication are considered as potential environmental impacts and estimated by characterization factors given by the United States Environmental Protection Agency (EPA-TRACI). The benefits of corn stover removal are (1) lower nitrogen related environmental burdens from the soil, (2) higher ethanol production rate per unit arable land, and (3) energy recovery from lignin-rich fermentation residues, while the disadvantages of corn stover removal are a lower accumulation rate of soil organic carbon and higher fuel consumption in harvesting corn stover. Planting winter cover crops can compensate for some disadvantages (i.e., soil organic carbon levels and soil erosion) of removing corn stover. Cover crops also permit more corn stover to be harvested. Thus, utilization of corn stover and winter cover crops can improve the eco-efficiency of the cropping systems. When biomass from the cropping systems is utilized for biofuel production, all the cropping systems studied here offer environmental benefits in terms of nonrenewable energy consumption and global warming impact. Therefore utilizing biomass for biofuels would save nonrenewable energy, and reduce greenhouse gases. However, unless additional measures such as planting cover crops were taken, utilization of biomass for biofuels would also tend to increase acidification and eutrophication, primarily because large nitrogen (and phosphorus)-related environmental burdens are released from the soil during cultivation.     

Life cycle environmental impact comparison of solid oxide fuel cells fueled by natural gas,hydrogen, ammonia and methanol for combined heat and power generation

This study aims to provide a comprehensive environmental life cycle assessment of heat and power production through solid oxide fuel cells (SOFCs) fueled by various chemical feeds namely; natural gas, hydrogen, ammonia and methanol. The life cycle assessment (LCA) includes the complete phases from raw material extraction or chemical fuel synthesis to consumption in the electrochemical reaction as a cradle-to-grave approach. The LCA study is performed using GaBi software, where the selected impact assessment methodology is ReCiPe 1.08. The selected environmental impact categories are climate change, fossil depletion, human toxicity, water depletion, particulate matter formation, and photochemical oxidant formation. The production pathways of the feed gases are selected based on the mature technologies as well as emerging water electrolysis via wind electricity. Natural gas is extracted from the wells and processed in the processing plant to be fed to SOFC. Hydrogen is generated by steam methane reforming method using the natural gas in the plant. Methanol is also produced by steam methane reforming and methanol synthesis reaction. Ammonia is synthesized using the hydrogen obtained from steam methane reforming and combined with nitrogen from air in a Haber-Bosch plant. Both hydrogen and ammonia are also produced via wind energy-driven decentralized electrolysis in order to emphasize the cleaner fuel production. The results of this study show that feeding SOFC systems with carbon-free fuels eliminates the greenhouse gas emissions during operation, however additional steps required for natural gas to hydrogen, ammonia and methanol conversion, make the complete process more environmentally problematic. However, if hydrogen and ammonia are produced from renewable sources such as wind-based electricity, the environmental impacts reduce significantly, yielding about 0.05 and 0.16 kg CO₂ eq., respectively, per kWh electricity generation from SOFC.     

A LCA (life cycle assessment) of the methanol production from sugarcane bagasse

Nowadays one of the most important environmental issues is the exponential increase of the greenhouse effect by the polluting action of the industrial and transport sectors. The production of biofuels is considered a viable alternative for the pollution mitigation but also to promote rural development. The work presents an analysis of the environmental impacts of the methanol production from sugarcane bagasse, taking into consideration the balance of the energy life cycle and its net environmental impacts, both are included in a LCA (Life Cycle Assessment) approach. The evaluation is done as a case study of a 100,000 t/y methanol plant, using sugarcane bagasse as raw material. The methanol is produced through the BTL (Biomass to Liquid) route. The results of the environmental impacts were compared to others LCA studies of biofuel and it was showed that there are significant differences of environmental performance among the existing biofuel production system, even for the same feedstock. The differences are dependent on many factors such as farming practices, technology of the biomass conversion. With relation to the result of output/input ratio, the methanol production from sugarcane bagasse showed to be a feasible alternative for the substitution of an amount of fossil methanol obtained from natural gas.     

Assessing the environmental performance and sustainability of bioenergy production in Sweden: A life cycle assessment perspective

Bioenergy is one of the most dynamic and rapidly changing sectors of the global energy economy. The use of food crops for conversion to biofuel has been criticized for several reasons, among which its competition with the global food chain. Instead, lignocellulosic substrates are claimed to provide a bioenergy alternative without competing with food demand. This is particularly true when dealing with residues or waste. In this paper, we explored the environmental performance and sustainability of a bioenergy production system that integrates wastewater treatment, willow farming, and a Combined Heat and Power plant (CHP) located in Enköping (Sweden). Several methodologies for environmental assessment are integrated in this study within a life cycle perspective to investigate material and energy requirements as well as emissions and related impacts of the whole bioenergy production chain. Results show that full integration of different subsystems of a productive network is a desirable option for bioenergy production, within a zero emission oriented production pattern. The investigated wood biomass powered CHP plant was able to co-generate heat and electricity with high production efficiency and much better environmental performance and sustainability than fossil fuel based power plants.     

The energy and environmental implications of UK more electric transition pathways: A whole systems perspective

Electricity generation contributes a large proportion of the total greenhouse gas emissions in the United Kingdom (UK), due to the predominant use of fossil fuel (coal and natural gas) inputs. Indeed, the various power sector technologies [fossil fuel plants with and without carbon capture and storage (CCS), nuclear power stations, and renewable energy technologies (available on a large and small {or domestic} scale)] all involve differing environmental impacts and other risks. Three transition pathways for a more electric future out to 2050 have therefore been evaluated in terms of their life-cycle energy and environmental performance within a broader sustainability framework. An integrated approach is used here to assess the impact of such pathways, employing both energy analysis and environmental life-cycle assessment (LCA), applied on a ‘whole systems’ basis: from ‘cradle-to-gate’. The present study highlights the significance of ‘upstream emissions’, in contrast to power plant operational or ‘stack’ emissions, and their (technological and policy) implications. Upstream environmental burdens arise from the need to expend energy resources in order to deliver, for example, fuel to a power station. They include the energy requirements for extraction, processing/refining, transport, and fabrication, as well as methane leakage that occurs in coal mining activities – a major cotribution – and from natural gas pipelines. The impact of upstream emissions on the carbon performance of various low carbon electricity generators [such as large-scale combined heat and power (CHP) plant and CCS] and the pathways distinguish the present findings from those of other UK analysts. It suggests that CCS is likely to deliver only a 70% reduction in carbon emissions on a whole system basis, in contrast to the normal presumption of a 90% reduction. Similar results applied to other power generators.     

The application of ecosystems services criteria for green building assessment

In the discussion of environmental architecture, we are conjoining two disciplines, the subject of architecture and that of ecology. At their best, green buildings are examples of applied ecology, where designers understand the constitution, organization, and structure of ecosystems, and the impacts of architecture are considered from an environmental perspective. By utilizing the concepts, methods, and language of ecology, designers can create architecture that intentionally engages the natural systems of a site.The establishment of assessment criteria implies the definition of building design criteria. If we establish criteria that are based on our best scientific understanding of environmental capacity, we will begin to develop a building stock that is sustainable. To do this we must quantify the link between the resulting environmental impacts and their cause in building production and use. This is not done in traditional building environmental impact assessment methods, which are based on quantifying assumed negative impacts of man-made interventions on the natural environment, typically using a code compliant reference building as a standard to improve upon. These indexes lack an ecologically derived baseline, or standard of measure, under which sustainable developments can be analyzed and compared on a universal basis.An ecologically derived baseline can be used to measure negative impacts as well as positive impacts of buildings. It also allows vastly different project types, sizes and locations to be compared on an equal basis. This study extends the concept of ecological capacity into an architectural context, and develops carrying capacity as a time and area dependent tool to evaluate the effectiveness of environmental building design. The ecosystem services criteria study uses an objective metric of carrying capacity as an ecologically derived baseline (hectare/years) to assess building sustainability. The farmhouse, a low energy, biological material based building located in Boulder, Colorado is evaluated to show the application of this method. The relative ecological impact of energy and materials for this project is described, as well as identification of effective strategies for reducing environmental impacts of typical buildings.     

An integrated assessment of a large-scale biodiesel production in Italy: Killing several birds with one stone?

Biofuels are often presented as a contribution towards the solution of the problems related to our strong dependency on fossil fuels, i.e. greenhouse effect, energy dependency, urban pollution, besides being a way to support rural development. In this paper, an integrated assessment approach is employed to discuss the social desirability of a large-scale biodiesel production in Italy, taking into account social, environmental and economic factors. The conclusion is that the advantages in terms of reduction of greenhouse gas emissions, energy dependency and urban pollution would be very modest. The small benefits would not be enough to offset the huge costs in terms of land requirement: if the target of the European Directive 2003/30/EC were reached (5.75% of the energy used for transport by 2010) the equivalent of about one-third of the Italian agricultural land would be needed. The consequences would be a considerable increase in food imports and large environmental impacts in the agricultural phase. Also, since biodiesel must be de-taxed in order to make it competitive with oil-derived diesel, the Italian energy revenues would be reduced. In the end, rural development remains the only sound reason to promote biodiesel, but even for this objective other strategies look more advisable, like supporting organic agriculture.