Publications
11 results found
Le Varlet T, Schmidt O, Gambhir A, et al., 2020, Comparative life cycle assessment of lithium-ion battery chemistries for residential storage, Journal of Energy Storage, Vol: 28, ISSN: 2352-152X
Residential storage deployment is expected to grow dramatically over the coming decade. Several lithium-ion chemistries are employed, but the relative environmental impacts of manufacturing them is poorly understood. This study presents a cradle-to-gate life cycle assessment to quantify the environmental impact of five prominent lithium-ion chemistries, based on the specifications of 73 commercially-available battery modules used for residential applications. Three impact categories (global warming potential, cumulative energy demand and mineral resource scarcity) are analysed across two functional units (storage capacity and lifetime energy delivered). Most chemistries have embodied carbon footprints of around 200 kg CO2e per kWh of useable storage capacity, which corresponds to 43–84 g CO2e per kWh of lifetime energy delivered with daily cycling operation. Energy delivered on energy invested is also calculated at values of 2–4, which falls to 0.54–0.66 with the energy for charging included (cf. a round-trip efficiency of 82–89%). Environmental impact depends more on cycling frequency than chemistry choice, and none of the battery chemistries convincingly outperforms the others. Cells only constitute a third to a half of the environmental impact, which is comparable to the inverter. Routes to making residential lithium-ion battery systems more environmentally benign include reducing the reliance on cobalt, nickel and copper, increasing the specific useable energy, developing comprehensive recycling initiatives, and maximising the utilisation (cycle frequency) once in operation.
Gardiner D, Schmidt O, Heptonstall P, et al., 2020, Quantifying the impact of policy on the investment case for residential electricity storage in the UK, Journal of Energy Storage, Vol: 27, ISSN: 2352-152X
Electrical energy storage has a critical role in future energy systems, but deployment is constrained by high costs and barriers to ‘stacking’ multiple revenue streams. We analyse the effects of different policy measures and revenue stacking on the economics of residential electricity storage in the UK. We identify six policy interventions through industry interviews and quantify their impact using a techno-economic model of a 4kWh battery paired with a 4kW solar system. Without policy intervention, residential batteries are not currently financially viable in the UK. Policies that enable access to multiple revenue streams, rather than just maximising PV self-consumption, improve this proposition. Demand Load-Shifting and Peak Shaving respectively increase the net present value per unit of investment cost (NPV/Capex) by 30% and 9% respectively. Given projected reductions in storage costs, stacking these services brings forward the break even date for residential batteries by 9 years to 2024, and increases the effectiveness of policies that reduce upfront costs, suggesting that current policy is correctly focused on enabling revenue stacking. However, additional support is needed to accelerate deployment in the near term. Combining revenue stacking with a subsidy of £250 per kWh or zero-interest loans could make residential storage profitable by 2020.
Kittner N, Tsiropoulos I, Tarvydas D, et al., 2020, Electric vehicles, TECHNOLOGICAL LEARNING IN THE TRANSITION TO A LOW-CARBON ENERGY SYSTEM: CONCEPTUAL ISSUES, EMPIRICAL FINDINGS, AND USE, IN ENERGY MODELING, Editors: Junginger, Louwen, Publisher: ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, Pages: 145-163, ISBN: 978-0-12-818762-3
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Few S, Schmidt O, Gambhir A, 2019, Energy access through electricity storage: Insights from technology providers and market enablers, Energy For Sustainable Development, Vol: 48, Pages: 1-10, ISSN: 0973-0826
In recent years, deployment of standalone electricity systems to provide energy access in a rural context has increased rapidly. These systems typically incorporating variable renewables alongside electrical energy storage for consistent supply, and operate at a range of scales to provide a range of services. However, there has been relatively little analysis of storage technology choices made by providers of these systems, how this varies by application, how these are influenced by priorities of providers, and how these choices could be improved. Here, we present findings from a series of interviews with providers of off grid energy solutions on choice and availability of technologies, supply chains, realised costs, technology performance, environmental impact, and anticipated impact of future technology development. Based upon these, we make recommendations for regulators and individual companies on how technology choices and life cycle management could be improved.
Schmidt O, Melchior S, Hawkes A, et al., 2019, Projecting the future levelized cost of electricity storage technologies, Joule, Vol: 3, Pages: 81-100, ISSN: 2542-4351
The future role of stationary electricity storage is perceived as highly uncertain. One reason is that most studies into the future cost of storage technologies focus on investment cost. An appropriate cost assessment must be based on the application-specific lifetime cost of storing electricity. We determine the levelized cost of storage (LCOS) for 9 technologies in 12 power system applications from 2015 to 2050 based on projected investment cost reductions and current performance parameters. We find that LCOS will reduce by one-third to one-half by 2030 and 2050, respectively, across the modeled applications, with lithium ion likely to become most cost efficient for nearly all stationary applications from 2030. Investments in alternative technologies may prove futile unless significant performance improvements can retain competitiveness with lithium ion. These insights increase transparency around the future competitiveness of electricity storage technologies and can help guide research, policy, and investment activities to ensure cost-efficient deployment.
Few SPM, Schmidt O, Offer GJ, et al., 2018, Prospective improvements in cost and cycle life of off-grid lithium-ion battery packs: An analysis informed by expert elicitations, Energy Policy, Vol: 114, Pages: 578-590, ISSN: 0301-4215
This paper presents probabilistic estimates of the 2020 and 2030 cost and cycle life of lithium-ion battery (LiB) packs for off-grid stationary electricity storage made by leading battery experts from academia and industry, and insights on the role of public research and development (R&D) funding and other drivers in determining these. By 2020, experts expect developments to arise chiefly through engineering, manufacturing and incremental chemistry changes, and expect additional R&D funding to have little impact on cost. By 2030, experts indicate that more fundamental chemistry changes are possible, particularly under higher R&D funding scenarios, but are not inevitable. Experts suggest that significant improvements in cycle life (eg. doubling or greater) are more achievable than in cost, particularly by 2020, and that R&D could play a greater role in driving these. Experts expressed some concern, but had relatively little knowledge, of the environmental impact of LiBs. Analysis is conducted of the implications of prospective LiB improvements for the competitiveness of solar photovoltaic + LiB systems for off-grid electrification.
Schmidt O, Gambhir A, Staffell IL, et al., 2017, Future cost and performance of water electrolysis: An expert elicitation study, International Journal of Hydrogen Energy, Vol: 42, Pages: 30470-30492, ISSN: 0360-3199
The need for energy storage to balance intermittent and inflexible electricity supply with demand is driving interest in conversion of renewable electricity via electrolysis into a storable gas. But, high capital cost and uncertainty regarding future cost and performance improvements are barriers to investment in water electrolysis. Expert elicitations can support decision-making when data are sparse and their future development uncertain. Therefore, this study presents expert views on future capital cost, lifetime and efficiency for three electrolysis technologies: alkaline (AEC), proton exchange membrane (PEMEC) and solid oxide electrolysis cell (SOEC). Experts estimate that increased R&D funding can reduce capital costs by 0–24%, while production scale-up alone has an impact of 17–30%. System lifetimes may converge at around 60,000–90,000 h and efficiency improvements will be negligible. In addition to innovations on the cell-level, experts highlight improved production methods to automate manufacturing and produce higher quality components. Research into SOECs with lower electrode polarisation resistance or zero-gap AECs could undermine the projected dominance of PEMEC systems. This study thereby reduces barriers to investment in water electrolysis and shows how expert elicitations can help guide near-term investment, policy and research efforts to support the development of electrolysis for low-carbon energy systems.
Schmidt O, Hawkes, Gambhir, et al., 2017, The future cost of electrical energy storage based on experience rates, Nature Energy, Vol: 2, ISSN: 2058-7546
Electrical energy storage could play a pivotal role in future low-carbon electricity systems, balancing inflexible or intermittentsupply with demand. Cost projections are important for understanding this role, but data are scarce and uncertain.Here, we construct experience curves to project future prices for 11 electrical energy storage technologies. We find that,regardless of technology, capital costs are on a trajectory towards US$340 ± 60 kWh−1for installed stationary systems andUS$175 ± 25 kWh−1for battery packs once 1 TWh of capacity is installed for each technology. Bottom-up assessment ofmaterial and production costs indicates this price range is not infeasible. Cumulative investments of US$175–510 billion wouldbe needed for any technology to reach 1 TWh deployment, which could be achieved by 2027–2040 based on market growthprojections. Finally, we explore how the derived rates of future cost reduction influence when storage becomes economicallycompetitive in transport and residential applications. Thus, our experience-curve data set removes a barrier for further studyby industry, policymakers and academics.
Few SPM, Schmidt O, Gambhir A, 2016, Electrical energy storage for mitigating climate change, Publisher: Grantham Institute, Imperial College London, 20
Titilayo S, Schmidt, Wen P, et al., 2012, Novel nano-scale Au/α-Fe₂O₃ catalyst for the preferential oxidation of CO in biofuel reformate gas, Journal of Catalysis, ISSN: 1090-2694
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