41 results found
Lowes R, Woodman B, Speirs J, 2020, Heating in Great Britain: An incumbent discourse coalition resists an electrifying future, Environmental Innovation and Societal Transitions, Vol: 37, Pages: 1-17, ISSN: 2210-4224
Speirs J, Jalil-Vega F, Cooper J, et al., 2020, The flexibility of gas - what is it worth?, White Paper 5: The Flexibility of gas – what is it worth?, London, UK, Publisher: Sustainable Gas Institute, Imperial College London, 5
What is the evidence on the flexibility value that gas vectors and gas networks can provide to support the future energy system?There is an increasing debate regarding the use of gas networks in providing support for the decarbonisation of energy systems.The perceived value of gas “vectors” – encompassing natural gas, hydrogen and biomethane – is that they may provide flexibility, helping to support daily and seasonal variation in energy demand, and increasingly intermittent electricity supply as renewable electricity generation increases as a proportion of the electricity mix.Arguments in support of gas suggest that electricity systems will find it difficult to maintain flexibility on their own, whilst also reducing greenhouse gas emissions and increasing production to meet new demand for heating and transport. Gas, on the other hand, is expected to provide flexibility at relatively low cost, and may be produced and used with relatively low greenhouse gas emissions.White Paper 5 investigates the evidence surrounding the flexibility provided by gas and gas networks and the cost of, and value provided by gas to the future energy system.
Speirs J, Balcombe P, Blomerus P, et al., 2020, Natural gas fuel and greenhouse gas emissions in trucks and ships, Progress in Energy, Vol: 2, Pages: 012002-012002
Balcombe P, Brierley J, Lewis C, et al., 2019, How to decarbonise international shipping: Options for fuels, technologies and policies, Energy Conversion and Management, Vol: 182, Pages: 72-88, ISSN: 0196-8904
International shipping provides 80–90% of global trade, but strict environmental regulations around NOX, SOX and greenhouse gas (GHG) emissions are set to cause major technological shifts. The pathway to achieving the international target of 50% GHG reduction by 2050 is unclear, but numerous promising options exist. This study provides a holistic assessment of these options and their combined potential to decarbonise international shipping, from a technology, environmental and policy perspective. Liquefied natural gas (LNG) is reaching mainstream and provides 20–30% CO2 reductions whilst minimising SOX and other emissions. Costs are favourable, but GHG benefits are reduced by methane slip, which varies across engine types. Biofuels, hydrogen, nuclear and carbon capture and storage (CCS) could all decarbonise much further, but each faces significant barriers around their economics, resource potentials and public acceptability. Regarding efficiency measures, considerable fuel and GHG savings could be attained by slow-steaming, ship design changes and utilising renewable resources. There is clearly no single route and a multifaceted response is required for deep decarbonisation. The scale of this challenge is explored by estimating the combined decarbonisation potential of multiple options. Achieving 50% decarbonisation with LNG or electric propulsion would likely require 4 or more complementary efficiency measures to be applied simultaneously. Broadly, larger GHG reductions require stronger policy and may differentiate between short- and long-term approaches. With LNG being economically feasible and offering moderate environmental benefits, this may have short-term promise with minor policy intervention. Longer term, deeper decarbonisation will require strong financial incentives. Lowest-cost policy options should be fuel- or technology-agnostic, internationally applied and will require action now to ensure targets are met by 2050.
Speirs J, Balcombe P, Blomerus P, et al., 2019, Can natural gas reduce emissions from transport?: Heavy goods vehicles and shipping
Parkinson B, Balcombe P, Speirs JF, et al., 2019, Levelized cost of CO2 mitigation from hydrogen production routes, Energy and Environmental Science, Vol: 12, Pages: 19-40, ISSN: 1754-5692
Different technologies produce hydrogen with varying cost and carbon footprints over the entire resource supply chain and manufacturing steps. This paper examines the relative costs of carbon mitigation from a life cycle perspective for 12 different hydrogen production techniques using fossil fuels, nuclear energy and renewable sources by technology substitution. Production costs and life cycle emissions are parameterized and re-estimated from currently available assessments to produce robust ranges to describe uncertainties for each technology. Hydrogen production routes are then compared using a combination of metrics, levelized cost of carbon mitigation and the proportional decarbonization benchmarked against steam methane reforming, to provide a clearer picture of the relative merits of various hydrogen production pathways, the limitations of technologies and the research challenges that need to be addressed for cost-effective decarbonization pathways. The results show that there is a trade-off between the cost of mitigation and the proportion of decarbonization achieved. The most cost-effective methods of decarbonization still utilize fossil feedstocks due to their low cost of extraction and processing, but only offer moderate decarbonisation levels due to previous underestimations of supply chain emissions contributions. Methane pyrolysis may be the most cost-effective short-term abatement solution, but its emissions reduction performance is heavily dependent on managing supply chain emissions whilst cost effectiveness is governed by the price of solid carbon. Renewable electrolytic routes offer significantly higher emissions reductions, but production routes are more complex than those that utilise naturally-occurring energy-dense fuels and hydrogen costs are high at modest renewable energy capacity factors. Nuclear routes are highly cost-effective mitigation options, but could suffer from regionally varied perceptions of safety and concerns regarding prolife
Gross R, Hanna RF, Gambhir A, et al., 2018, How long does innovation and commercialisation in the energy sectors take? Historical case studies of the timescale from invention to widespread commercialisation in energy supply and end use technology, Energy Policy, Vol: 123, Pages: 685-699, ISSN: 0301-4215
Recent climate change initiatives, such as ‘Mission Innovation’ launched alongside the Paris Agreement in 2015, urge redoubled research into innovative low carbon technologies. However, climate change is an urgent problem – emissions reductions must take place rapidly throughout the coming decades. This raises an important question: how long might it take for individual technologies to emerge from research, find market opportunities and make a tangible impact on emissions reductions? Here, we consider historical evidence for the time a range of energy supply and energy end-use technologies have taken to emerge from invention, diffuse into the market and reach widespread deployment. We find considerable variation, from 20 to almost 70 years. Our findings suggest that the time needed for new technologies to achieve widespread deployment should not be overlooked, and that innovation policy should focus on accelerating the deployment of existing technologies as well as research into new ones.
Gross R, Hanna R, Gambhir A, et al., 2018, How long does innovation and commercialisation in the energy sectors take? Historical case studies of the timescale from invention to widespread commercialisation in energy supply and end use technology, Energy Policy, Vol: 123, Pages: 682-699, ISSN: 0301-4215
Balcombe P, Speirs JF, Brandon NP, et al., 2018, Methane emissions: choosing the right climate metric and time horizon, Environmental Science: Processes and Impacts, Vol: 20, Pages: 1323-1339, ISSN: 2050-7895
Methane is a more potent greenhouse gas (GHG) than CO2, but it has a shorter atmospheric lifespan, thus its relative climate impact reduces significantly over time. Different GHGs are often conflated into a single metric to compare technologies and supply chains, such as the global warming potential (GWP). However, the use of GWP is criticised, regarding: (1) the need to select a timeframe; (2) its physical basis on radiative forcing; and (3) the fact that it measures the average forcing of a pulse over time rather than a sustained emission at a specific end-point in time. Many alternative metrics have been proposed which tackle different aspects of these limitations and this paper assesses them by their key attributes and limitations, with respect to methane emissions. A case study application of various metrics is produced and recommendations are made for the use of climate metrics for different categories of applications. Across metrics, CO2 equivalences for methane range from 4–199 gCO2eq./gCH4, although most estimates fall between 20 and 80 gCO2eq./gCH4. Therefore the selection of metric and time horizon for technology evaluations is likely to change the rank order of preference, as demonstrated herein with the use of natural gas as a shipping fuel versus alternatives. It is not advisable or conservative to use only a short time horizon, e.g. 20 years, which disregards the long-term impacts of CO2 emissions and is thus detrimental to achieving eventual climate stabilisation. Recommendations are made for the use of metrics in 3 categories of applications. Short-term emissions estimates of facilities or regions should be transparent and use a single metric and include the separated contribution from each GHG. Multi-year technology assessments should use both short and long term static metrics (e.g. GWP) to test robustness of results. Longer term energy assessments or decarbonisation pathways must use both short and long-term metrics and where this has a lar
Balcombe P, Speirs J, Johnson E, et al., 2018, The carbon credentials of hydrogen gas networks and supply chains, Renewable and Sustainable Energy Reviews, Vol: 91, Pages: 1077-1088, ISSN: 1364-0321
Projections of decarbonisation pathways have typically involved reducing dependence on natural gas grids via greater electrification of heat using heat pumps or even electric heaters. However, many technical, economic and consumer barriers to electrification of heat persist. The gas network holds value in relation to flexibility of operation, requiring simpler control and enabling less expensive storage. There may be value in retaining and repurposing gas infrastructure where there are feasible routes to decarbonisation. This study quantifies and analyses the decarbonisation potential associated with the conversion of gas grids to deliver hydrogen, focusing on supply chains. Routes to produce hydrogen for gas grids are categorised as: reforming natural gas with (or without) carbon capture and storage (CCS); gasification of coal with (or without) CCS; gasification of biomass with (or without) CCS; electrolysis using low carbon electricity. The overall range of greenhouse gas emissions across routes is extremely large, from − 371 to 642 gCO 2 eq/kW h H2 . Therefore, when including supply chain emissions, hydrogen can have a range of carbon intensities and cannot be assumed to be low carbon. Emissions estimates for natural gas reforming with CCS lie in the range of 23–150 g/kW h H2 , with CCS typically reducing CO 2 emissions by 75%. Hydrogen from electrolysis ranges from 24 to 178 gCO 2 eq/kW h H2 for renewable electricity sources, where wind electricity results in the lowest CO 2 emissions. Solar PV electricity typically exhibits higher emissions and varies significantly by geographical region. The emissions from upstream supply chains is a major contributor to total emissions and varies considerably across different routes to hydrogen. Biomass gasification is characterised by very large negative emissions in the supply chain and very large positive emissions in the gasification process. Therefore, improvements in total emissions are large if even small i
There is an ongoing debate over future decarbonisation of gas networks using biomethane, and increasingly hydrogen, in gas network infrastructure. Some emerging research presents gas network decarbonisation options as a tractable alternative to ‘all-electric’ scenarios that use electric appliances to deliver the traditional gas services such as heating and cooking. However, there is some uncertainty as to the technical feasibility, cost and carbon emissions of gas network decarbonisation options. In response to this debate the Sustainable Gas Institute at Imperial College London has conducted a rigorous systematic review of the evidence surrounding gas network decarbonisation options. The study focuses on the technologies used to generate biomethane and hydrogen, and examines the technical potentials, economic costs and emissions associated with the full supply chains involved. The following summarises the main findings of this research. The report concludes that there are a number of options that could significantly decarbonise the gas network, and doing so would provide energy system flexibility utilising existing assets. However, these options will be more expensive than the existing gas system, and the GHG intensity of these options may vary significantly. In addition, more research is required, particularly in relation to the capabilities of existing pipework to transport hydrogen safely.
Speirs JF, Balcombe P, Johnson E, et al., 2017, A Greener Gas Grid: What are the options
Balcombe P, Anderson K, Speirs J, et al., 2016, The natural gas supply chain: the importance of methane and carbon dioxide emissions, ACS Sustainable Chemistry & Engineering, Vol: 5, Pages: 3-20, ISSN: 2168-0485
Natural gas is typically considered to be the cleaner-burning fossil fuel that could play an important role within a restricted carbon budget. While natural gas emits less CO2 when burned than other fossil fuels, its main constituent is methane, which has a much stronger climate forcing impact than CO2 in the short term. Estimates of methane emissions in the natural gas supply chain have been the subject of much controversy, due to uncertainties associated with estimation methods, data quality, and assumptions used. This Perspective presents a comprehensive compilation of estimated CO2 and methane emissions across the global natural gas supply chain, with the aim of providing a balanced insight for academia, industry, and policy makers by summarizing the reported data, locating the areas of major uncertainty, and identifying where further work is needed to reduce or remove this uncertainty. Overall, the range of documented estimates of methane emissions across the supply chain is vast among an aggregation of different geological formations, technologies, plant age, gas composition, and regional regulation, not to mention differences in estimation methods. Estimates of combined methane and CO2 emissions ranged from 2 to 42 g CO2 eq/MJ HHV, while methane-only emissions ranged from 0.2% to 10% of produced methane. The methane emissions at the extraction stage are the most contentious issue, with limited data available but potentially large impacts associated with well completions for unconventional gas, liquids unloading, and also the transmission stage. From the range of literature estimates, a constrained range of emissions was estimated that reflects the most recent and reliable estimates: total supply chain GHG emissions were estimated to be between 3.6 and 42.4 g CO2 eq/MJ HHV, with a central estimate of 10.5. The presence of “super emitters”, a small number of facilities or equipment that cause extremely high emissions, is found across all supply chai
Hanna R, Gross R, Speirs J, et al., 2015, Innovation timelines from invention to maturity: A rapid review of the evidence on the time taken for new technologies to reach widespread commercialisation
Balcombe P, Anderson K, Speirs J, et al., 2015, Methane and CO2 emissions from the natural gas supply chain: an evidence assessment, Publisher: Sustainable Gas Institute
Speirs J, McGlade C, Slade R, 2015, Uncertainty in the availability of natural resources: Fossil fuels, critical metals and biomass, Energy Policy, Vol: 87, Pages: 654-664, ISSN: 0301-4215
Energy policies are strongly influenced by resource availability and recoverability estimates. Yet these estimates are often highly uncertain, frequently incommensurable, and regularly contested. This paper explores how the uncertainties surrounding estimates of the availability of fossil fuels, biomass and critical metals are conceptualised and communicated. The contention is that a better understanding of the uncertainties surrounding resource estimates for both conventional and renewable energy resources can contribute to more effective policy decision making in the long term. Two complementary approaches for framing uncertainty are considered in detail: a descriptive typology of uncertainties and a framework that conceptualises uncertainty as alternative states of incomplete knowledge. Both have the potential to be useful analytical and communication tools. For the three resource types considered here we find that data limitations, inconsistent definitions and the use of incommensurable methodologies present a pervasive problem that impedes comparison. Many aspects of resource uncertainty are also not commonly captured in the conventional resource classification schemes. This highlights the need for considerable care when developing and comparing aggregate resource estimates and when using these to inform strategic energy policy decisions.
Speirs JF, McGlade C, Slade, 2015, Uncertainty in the availability of natural resources: Fossil fuels, critical metals and biomass, Energy Policy, ISSN: 0301-4215
Speirs, mcglade, slade, 2015, Uncertainty in the availability of natural resources: Fossil fuels, critical metals and biomass, Energy Policy, ISSN: 0301-4215
Gross R, Speirs JF, hawkes, et al., 2014, Could retaining old coal lead to a policy own goal? Modelling the potential or coal fired power stations to undermine carbon targets in 2030
Speirs J, Gross R, Candelise C, et al., 2014, Materials Availability for Low Carbon Technologies, Publisher: UKERC
Speirs J, Contestabile M, Houari Y, et al., 2014, The future of lithium availability for electric vehicle batteries, Renewable and Sustainable Energy Reviews, Vol: 35, Pages: 183-193, ISSN: 1364-0321
Electric vehicles using lithium batteries could significantly reduce the emissions associated with road vehicle transport. However, the future availability of lithium is uncertain, and the feasibility of manufacturing lithium batteries at sufficient scale has been questioned. The levels of lithium demand growth implied by electric vehicle deployment scenarios is significant, particularly where scenarios are consistent with global GHG reduction targets. This paper examines the question of future lithium availability for the manufacturing of lithium batteries for electric vehicles.In this paper we first examine some of the existing literature in this area, highlighting the levels of future lithium demand previously considered and pointing to the variables that give rise to the range of outcomes in these assessments. We then investigate the ways in which lithium availability is calculated in the literature based on both lithium demand from electric vehicles and lithium supply from both brines and ore.This paper particularly focuses on the key variables needed to make an assessment of future lithium availability. On the demand side, these variables include future market size of electric vehicles, their average battery capacity and the material intensity of the batteries. The key supply variables include global reserve and resource estimates, forecast production and recyclability.We found that the literature informing assumptions regarding the key variables is characterised by significant uncertainty. This uncertainty gives rise to a wide range of estimates for the future demand for lithium based on scenarios consistent with as 50% reduction in global emissions by 2050 at between 184,000 and 989,000 t of lithium per year in 2050. However, lithium production is forecast to grow to between 75,000 and 110,000 t per year by 2020. Under this rate of production growth, it is plausible that lithium supply will meet increasing lithium demand over the coming decades to 2050.
Sorrell S, Speirs J, 2014, Using growth curves to forecast regional resource recovery: approaches, analytics and consistency tests, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 372, ISSN: 1364-503X
Houari Y, Speirs J, Candelise C, et al., 2013, A system dynamics model of tellurium availability for CdTe PV, Progress in Photovoltaics: Research and Applications, Pages: n/a-n/a, ISSN: 1099-159X
The routine availability of key component materials has been highlighted as a potential constraint to both extensive deployment and reduction in production costs of thin-film photovoltaic (PV) technologies. This paper examines the effect of material availability on the maximum potential growth of thin-film PV by 2050 using the case of tellurium (Te) in cadmium telluride (CdTe) PV, currently the dominating thin-film technology with the lowest manufacturing cost. The use of system dynamics (SD) modelling allows for a dynamic treatment of key Te supply features and prospects for reductions in PV demand via material efficiency improvements, as well as greater transparency and a better understanding of future recycling potential. The model's projections for maximum Te-constrained CdTe PV growth by 2050 are shown to be higher than a number of previous studies using static assumptions—suggesting that a dynamic treatment of the resource constraints for CdTe inherently improves the outlook for future deployment of this technology. In addition, the sensitivity analysis highlights certain complex correlations between the maximum potential CdTe growth by 2050 and the rated lifetime of PV modules as well as the reported size of global Te resources. The highest observed sensitivities are to the recovery rate of Te from copper anode slimes, the active layer thickness, the module efficiency and the utilisation rate of Te during manufacturing, all of which are highlighted as topics for further research. Copyright © 2013 John Wiley & Sons, Ltd.
McGlade C, Speirs J, Sorrell S, 2013, Methods of estimating shale gas resources - Comparison, evaluation and implications, ENERGY, Vol: 59, Pages: 116-125, ISSN: 0360-5442
Gross R, Heptonstall P, Speirs J, et al., 2013, Review of the Fourth Carbon Budget - Call for Evidence: Response from the Centre for Energy Policy and Technology, Imperial College London (ICEPT), London, Publisher: Committee on Climate Change
McGlade C, Speirs J, Sorrell S, 2013, Unconventional gas - A review of regional and global resource estimates, Energy, Vol: In Press
Sorrell S, Speirs J, Bentley R, et al., 2012, Shaping the global oil peak: A review of the evidence on field sizes, reserve growth, decline rates and depletion rates, Energy, Vol: 37, Pages: 709-724, ISSN: 0360-5442
This review paper summarises and evaluates the evidence regarding four issues that are considered to be of critical importance for future global oil supply. These are: a) how regional and global oil resources are distributed between different sizes of field; b) why estimates of the recoverable resources from individual fields tend to grow over time and the current and likely future contribution of this to global reserve additions; c) how rapidly the production from different categories of field is declining and how this may be expected to change in the future; and d) how rapidly the remaining recoverable resources in a field or region can be produced. It is shown that, despite serious data limitations, the level of knowledge of each of these issues has improved considerably over the past decade. While the evidence on reserve growth appears relatively encouraging for future global oil supply, that on decline and depletion rates does not. Projections of future global oil supply that use assumptions inconsistent with this evidence base are likely to be in error.
Candelise C, Speirs J, Gross R, 2011, Materials availability for thin film (TF) PV technologies development: a real concern?, Renewable and Sustainable Energy Reviews, Vol: 15, Pages: 4972-4981, ISSN: 1364-0321
Decarbonisation goals have triggered photovoltaic (PV) sector expansion and cost reductions in PV technologies. Thin film (TF) PV technologies are currently the cheapest to manufacture and offer the possibility of attaining lower costs. However, scarcity of key component materials has been highlighted as a potential barrier to both large scale deployment and reductions in technology cost. This paper explores this claim for cadmium telluride (CdTe) and copper indium gallium (di)selenide (CIGS) TF technologies and their potentially constraining materials, tellurium and indium. It reviews key literature, highlighting the high uncertainty in the estimates of the resource constrained TF PV potential as well as in data and methodologies used to assess future availability of the targeted materials. The reviewed evidence does not support the contention that the availability of tellurium and indium will necessarily constrain CdTe and CIGS technologies respectively in their ability to supply expected future PV market growth. However, future escalation in indium and tellurium price resulting from demand–supply imbalances could have a negative impact on CdTe and CIGS cost reduction ambitions. Factors influencing indium and tellurium price and their relative contribution to TF PV module production cost need further investigation.
Sorrell S, Miller R, Bentley R, et al., 2010, Oil futures: A comparison of global supply forecasts, Energy Policy, Vol: In Press, Corrected Proof, ISSN: 0301-4215
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