Challenges in Quantifying Greenhouse Gas Impacts of Waste-Based Biofuels in EU and US Biofuel Policies: Case Study of Butanol and Ethanol Production from Municipal Solid Waste

Conversion of wastes to biofuels is a promising route to provide renewable low-carbon fuels, based on a low- or negative-cost feedstock, whose use can avoid negative environmental impacts of conventional waste treatment. However, current policies that employ LCA as a quantitative measure are not adequate for assessing this type of fuel, given their cross-sector interactions and multiple potential product/service streams (energy, fuels, materials, waste treatment service). We employ a case study of butanol and ethanol production from mixed municipal solid waste to demonstrate the challenges in using life cycle assessment to appropriately inform decision-makers. Greenhouse gas emissions results vary from −566 gCO2 eq/MJbiofuel (under US policies that employ system expansion approach) to +86 gCO2 eq/MJbiofuel and +23 gCO2 eq/MJbiofuel (under initial and current EU policies that employ energy-based allocation), relative to gasoline emissions of +94 gCO2 eq. LCA methods used in existing policies thus provide contradictory information to decision-makers regarding the potential for waste-based biofuels. A key factor differentiating life cycle assessment methodologies is the inclusion of avoided impacts of conventional waste treatment in US policies and their exclusion in EU policies. Present EU rules risk discouraging the valorisation of wastes to biofuels thus forcing waste toward lower-value treatment processes and products

Environmental and cost analysis of carbon fibre composites recycling

While carbon fibre reinforced plastic (CFRP) can reduce transportation energy use and greenhouse gas emissions by reducing vehicle weight, the production of virgin carbon fibre (CF) itself is energy intensive. CFRP recycling and the reutilisation of the recovered CF have the potential to compensate for the high impact of virgin CF production due to low cost and to open up new composites markets – e.g., in the automotive sector. The aim of the research is to examine the life cycle environmental and financial implications of a fluidised bed process to recycle CFRP wastes and to identify potential markets for CFRP reuse in automotive applications. Firstly, process models of the fluidised bed carbon fibre recycling technologies are developed based on thermodynamic principles and established modelling techniques to quantify the heat and electricity requirements and predict the energy efficiency of a hypothetical commercial-scale plant. The energy model shows that the energy requirement of recycled CF production is generally less than 10% relative to virgin CF and results are robust across likely operating conditions. Further optimisation of the fluidised bed recycling process is needed to balance to the feed rate per unit bed area to minimise process energy use and potential implications for recycled CF properties. Opportunities exist for recovering stack heat loss which could further improve the energy efficiency of the fluidised bed process. Secondly, process models for recycled CF processing (i.e., wet-papermaking/ fibre alignment) and subsequent CFRP manufacture (i.e., compression moulding/ injection moulding) technologies are developed to quantify the energy and material requirements of a hypothetical operating facility. Models are based on optimised parameters based on the best performance from previous experiments, where available, while target values are used for the fibre alignment technologies currently under development. Thirdly, the life cycle environmental implications of recovering carbon fibre and producing composite materials as substitutes for conventional materials (e.g., steel, aluminium, virgin CFRP) are assessed and proposed as lightweight materials in automotive applications, based on process models of the fluidised bed recycling process and remanufacturing processes or available life cycle assessment databases. Life cycle impact assessments demonstrate the environmental benefits of recycled CFRP compared with end-of-life treatment options (landfilling, incineration). Recycled CF components can achieve the lowest life cycle environmental impacts of all materials considered, although the actual impact is highly dependent on the design criteria of the specific components. Low production impacts associated with recycled carbon fibre components are observed relative to lightweight competitor materials (e.g., aluminium, virgin CFRP). Recycled CF components also have low in-use fuel consumption due to mass reduction and associated reduction in mass-induced fuel consumption. The results demonstrate the potential environmental viability of recycled CF materials. Finally, financial analysis of carbon fibre recycling, processing, and use in recycled CFRP materials is undertaken to assess potential market opportunities in the automotive sector. Cost impacts of using recycled CF as a substitute for conventional materials are also assessed in the full life cycle, making use of data from energy and cost models, manufacturers and existing cost databases. Recovery of CF from CFRP wastes can be achieved at $5/kg and less across a wide range of process parameters. CFRP materials manufactured from recycled CF can offer cost savings and weight reductions relative to steel and competitor lightweight materials in some cases, but are dependent on the specific application and associated design constraints– e.g., the material design index - as this drives the weight reduction/in-use fuel consumption and material requirements. Fibre alignment could potentially improve financial performance by inducing larger vehicle in-use fuel cost savings associated with weight reductions. Further investigations to monetise environmental impacts show larger cost benefits for recycled CFRP materials in replacement of conventional steel and lightweight competitor materials

Techno-economic evaluation of multiple energy piles for a ground-coupled heat pump system

A technical and economic feasibility study of multiple energy piles (EPs) for a ground-coupled heat pump (GCHP) system is presented in this paper. The GCHP system energy performance and life-cycle cost (LCC) are evaluated, it is found that the system energy output (heating and cooling) could meet a domestic building comfortable environment requirement with the annual average COP of 3.63 and EER of 4.62. The LCC evaluation indicates that the system net present value (NPV) is approximately £26,095 at the market discount rate of 8.75% for a 20-year operating period. Moreover, the payback period of the GCHP system is approximately 4.31 years, which is sensitive to the main parameters including electricity price, capital investment and energy generation. Furthermore, the low discount rate and high energy generation are beneficial to the GCHP system with the high NPV and cash flows. The capital price of the system should be regulated to a lower level for the larger market potential

Wind turbine blade end-of-life options: an eco-audit comparison

Wind energy has developed rapidly over the last two decades to become one of the most promising economical and green sources of renewable energy, responding to concerns about use of fossil fuels and increasing demand for energy. However, attention is now turning to what happens to end-of-life wind turbine waste, and there is scrutiny of its environmental impact. In this study, we focus on one aspect of this, the blades. We analyse and compare end-of-life options for wind turbine blade materials (mainly glass fibre reinforced plastic and carbon fibre reinforced plastic) in terms of environmental impact (focusing on energy consumption), using our own data together with results gathered from the literature. The environmental impacts of each end-of-life option are discussed, looking at processing energy consumption, the recycling benefits and the effect of blade technology development trends. There is considerable variability in the results, and lack of consensus on predictions for the future. We therefore analyse the results using a range of different scenarios to show how the ‘optimal’ solutions are influenced by trends in blade composition and end-of-life process development. The most environmentally favourable process is dependent on whether the materials used for the blades are glass fibre composite or carbon fibre composite. The extent to which process improvement might affect the viability of different end-of-life processes has been assessed by looking at ‘crossover’ points for when the environmental impact becomes favourable. This analysis gives new insight into areas where research into process technologies could be targeted to enable significant end-of-life environmental benefits.China Scholarship Council Jesus College Cambridg

Environmental and cost analysis of carbon fibre composites recycling

While carbon fibre reinforced plastic (CFRP) can reduce transportation energy use and greenhouse gas emissions by reducing vehicle weight, the production of virgin carbon fibre (CF) itself is energy intensive. CFRP recycling and the reutilisation of the recovered CF have the potential to compensate for the high impact of virgin CF production due to low cost and to open up new composites markets – e.g., in the automotive sector. The aim of the research is to examine the life cycle environmental and financial implications of a fluidised bed process to recycle CFRP wastes and to identify potential markets for CFRP reuse in automotive applications. Firstly, process models of the fluidised bed carbon fibre recycling technologies are developed based on thermodynamic principles and established modelling techniques to quantify the heat and electricity requirements and predict the energy efficiency of a hypothetical commercial-scale plant. The energy model shows that the energy requirement of recycled CF production is generally less than 10% relative to virgin CF and results are robust across likely operating conditions. Further optimisation of the fluidised bed recycling process is needed to balance to the feed rate per unit bed area to minimise process energy use and potential implications for recycled CF properties. Opportunities exist for recovering stack heat loss which could further improve the energy efficiency of the fluidised bed process. Secondly, process models for recycled CF processing (i.e., wet-papermaking/ fibre alignment) and subsequent CFRP manufacture (i.e., compression moulding/ injection moulding) technologies are developed to quantify the energy and material requirements of a hypothetical operating facility. Models are based on optimised parameters based on the best performance from previous experiments, where available, while target values are used for the fibre alignment technologies currently under development. Thirdly, the life cycle environmental implications of recovering carbon fibre and producing composite materials as substitutes for conventional materials (e.g., steel, aluminium, virgin CFRP) are assessed and proposed as lightweight materials in automotive applications, based on process models of the fluidised bed recycling process and remanufacturing processes or available life cycle assessment databases. Life cycle impact assessments demonstrate the environmental benefits of recycled CFRP compared with end-of-life treatment options (landfilling, incineration). Recycled CF components can achieve the lowest life cycle environmental impacts of all materials considered, although the actual impact is highly dependent on the design criteria of the specific components. Low production impacts associated with recycled carbon fibre components are observed relative to lightweight competitor materials (e.g., aluminium, virgin CFRP). Recycled CF components also have low in-use fuel consumption due to mass reduction and associated reduction in mass-induced fuel consumption. The results demonstrate the potential environmental viability of recycled CF materials. Finally, financial analysis of carbon fibre recycling, processing, and use in recycled CFRP materials is undertaken to assess potential market opportunities in the automotive sector. Cost impacts of using recycled CF as a substitute for conventional materials are also assessed in the full life cycle, making use of data from energy and cost models, manufacturers and existing cost databases. Recovery of CF from CFRP wastes can be achieved at $5/kg and less across a wide range of process parameters. CFRP materials manufactured from recycled CF can offer cost savings and weight reductions relative to steel and competitor lightweight materials in some cases, but are dependent on the specific application and associated design constraints– e.g., the material design index - as this drives the weight reduction/in-use fuel consumption and material requirements. Fibre alignment could potentially improve financial performance by inducing larger vehicle in-use fuel cost savings associated with weight reductions. Further investigations to monetise environmental impacts show larger cost benefits for recycled CFRP materials in replacement of conventional steel and lightweight competitor materials

An assessment of financial viability of recycled carbon fibre in automotive applications

Carbon fibre (CF) recycling has been demonstrated to achieve reductions in environmental impacts compared to virgin CF production, but there is limited understanding of the financial viability of recycling and reutilisation of recycled CF (rCF). In this work, cost analysis and identification of market opportunities for rCF are performed by evaluating the cost of recycling, composite manufacture, and applications in automotive industry. Cost impacts of using rCF as a substitute for conventional materials and competitor lightweight materials are assessed over the full life cycle, including in-use implications. Recovery of CF can be achieved at $5/kg and less across a wide range of process parameters, approximately 15% of the cost of producing virgin carbon fibre. The life cycle cost results show that rCF composites, especially aligned rCF composites, give substantial cost reductions relative to virgin CF composites and even steel and aluminium

Development of an open-source carbon footprint calculator of the UK craft brewing value chain

Craft breweries may fall behind large brewing companies in reducing the carbon footprints of their value chains due to limited resources, financial constraints, and a lack of technical knowledge to fully understand their emissions. However, by increasing their awareness of the impact of their entire value chains, craft breweries can accelerate the decarbonisation of the industry by creating competition among breweries to appeal to environmentally conscious consumers. This work developed a freely available carbon calculator (10.6084/m9.figshare.22758692) using transparent, open-source data which may be used for benchmarking and identifying opportunities for emission reductions in UK craft breweries as well as providing a reference point for future carbon footprint analyses of global brewing value chains. The carbon footprint for craft brewing was calculated for a wide range of packaging types across three realistic scenarios (low, medium, and high carbon footprints) based on collected data and addresses the discrepancies between values reported in previous literature. Overall, the calculated carbon footprints ranged between 205 (20 L steel kegs, low carbon footprint scenario) and 1483 (single-use, 0.33 L glass bottles, high carbon footprint scenario) gCO2e per litre of beer. Novel hotspots (including wort boiling, the packaging process in a brewery, and the contribution of secondary and tertiary packaging) were identified. The overwhelming contribution of Scope 3 emissions (contributing between 57 and 95 % of the total carbon footprint) further emphasised the need to provide increased knowledge to craft breweries

Estimating the environmental impacts of global lithium-ion battery supply chain: A temporal, geographical, and technological perspective

A sustainable low-carbon transition via electric vehicles will require a comprehensive understanding of lithium-ion batteries’ global supply chain environmental impacts. Here, we analyze the cradle-to-gate energy use and greenhouse gas emissions of current and future nickel-manganese-cobalt and lithium-iron-phosphate battery technologies. We consider existing battery supply chains and future electricity grid decarbonization prospects for countries involved in material mining and battery production. Currently, around two-thirds of the total global emissions associated with battery production are highly concentrated in three countries as follows: China (45%), Indonesia (13%), and Australia (9%). On a unit basis, projected electricity grid decarbonization could reduce emissions of future battery production by up to 38% by 2050. An aggressive electric vehicle uptake scenario could result in cumulative emissions of 8.1 GtCO2eq by 2050 due to the manufacturing of nickel-based chemistries. However, a switch to lithium iron phosphate-based chemistry could enable emission savings of about 1.5 GtCO2eq. Secondary materials, via recycling, can help reduce primary supply requirements and alleviate the environmental burdens associated with the extraction and processing of materials from primary sources, where direct recycling offers the lowest impacts, followed by hydrometallurgical and pyrometallurgical, reducing greenhouse gas emissions by 61, 51, and 17%, respectively. This study can inform global and regional clean energy strategies to boost technology innovations, decarbonize the electricity grid, and optimize the global supply chain toward a net-zero future

Solutions for recycling emerging wind turbine blade waste in China are not yet effective

Wind power supply chains are evolving as markets expand to reach climate goals. With the largest installed wind power capacity globally, China must deal with increasing composite turbine waste and anticipate its associated costs. Here we predict the quantity and composition of wind turbine blade waste based on historic deployment. A high-resolution database containing 14 turbine capacities (150–5500 kilowatts) was compiled based on 104 turbine models. The environmental and financial costs of waste treatment options were evaluated using a bottom-up approach. Based on current installations and future projections, 7.7 to 23.1 million tonnes of blade waste will be generated in China by 2050. Technologies exist to recycle glass fibre from blade waste, but these solutions vary in level of maturity and are not always commercially available, cost-competitive, or environmentally sustainable. Our findings can inform decision-makers in governments and industry on the pathways to carbon neutrality

Solutions for recycling emerging wind turbine blade waste in China are not yet effective

These datasets include a high-resolution wind turbine blade waste database and environmental and cost datasets for China.</p