Publications
21 results found
Dubey L, Cooper J, Hawkes A, 2023, Minimum detection limits of the TROPOMI satellite sensor across North America and their implications for measuring oil and gas methane emissions, Science of the Total Environment, Vol: 872, Pages: 1-9, ISSN: 0048-9697
Methane emissions from natural gas are of ever-increasing importance as we struggle to reach Paris climate targets. Locating and measuring emissions from natural gas can be particularly difficult as they are often widely distributed across supply chains. Satellites are increasingly used to measure these emissions, with some such as TROPOMI giving daily coverage worldwide, making locating and quantifying these emissions easier. However, there is little understanding of the real-world detection limits of TROPOMI, which can cause emissions to go undetected or be misattributed. This paper uses TROPOMI and meteorological data to calculate, and create a map of, the minimum detection limits of the TROPOMI satellite sensor across North America for different campaign lengths. We then compared these to emission inventories to determine the quantity of emissions that can be captured by TROPOMI. We find that minimum detection limits vary from 500-8800 kg/h/pixel in a single overpass to 50-1200 kg/h/pixel for a yearlong campaign. This leads to 0.04 % of a year's emissions being captured in a single (day) measurement to 14.4 % in a 1-year measurement campaign. Assuming gas sites contain super-emitters, emissions of between 4.5 % - 10.1 % from a single measurement and 35.6 % - 41.1 % for a yearlong campaign are captured.
Dubey L, Cooper J, Staffell I, et al., 2023, Comparing satellite methane measurements to inventory estimates: a Canadian case study, Atmospheric Environment: X, Vol: 17, Pages: 1-9, ISSN: 2590-1621
Methane emissions from natural gas production are of increasing importance as they threaten efforts to mitigate climate change. Current inventory estimates carry high uncertainties due to difficulties in measuring emission sources across large regions. Satellite measurements of atmospheric methane could provide new understanding of emissions. This paper provides insight into the effectiveness of using satellite data to inform and improve methane inventories for natural gas activities. TROPOMI data are used to quantify methane emissions from natural gas within the Montney basin region of Canada and results are compared with existing inventories. Emissions estimated using TROPOMI data were 2.6 ± 2.2 kt/day which is 7.4 ± 6.4 times the inventory estimates. Pixels (7 by 7 km) that contained gas facilities had on average 11 ppb more methane than the background. 7.4% of pixels containing gas sites displayed consistently high methane levels that were not reflected in the inventory. The satellite data were not sufficiently granular to correlate with inventories on a facility scale. This illustrates the spatial limitations of using satellite data to corroborate bottom-up inventories.
Bakkaloglu S, Cooper J, Hawkes A, 2022, Life cycle environmental impact assessment of methane emissions from the biowaste management strategy of the United Kingdom: Towards net zero emissions, JOURNAL OF CLEANER PRODUCTION, Vol: 376, ISSN: 0959-6526
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Cooper J, Hawkes A, 2022, Cutting emissions outside borders, Nature Climate Change, Vol: 12, Pages: 965-966, ISSN: 1758-678X
Cooper J, Dubey L, Bakkaloglu S, et al., 2022, Hydrogen emissions from the hydrogen value chain-emissions profile and impact to global warming, Science of the Total Environment, Vol: 830, ISSN: 0048-9697
Future energy systems could rely on hydrogen (H2) to achieve decarbonisation and net-zero goals. In a similar energy landscape to natural gas, H2 emissions occur along the supply chain. It has been studied how current gas infrastructure can support H2, but there is little known about how H2 emissions affect global warming as an indirect greenhouse gas. In this work, we have estimated for the first time the potential emission profiles (g CO2eq/MJ H2,HHV) of H2 supply chains, and found that the emission rates of H2 from H2 supply chains and methane from natural gas supply are comparable, but the impact on global warming is much lower based on current estimates. This study also demonstrates the critical importance of establishing mobile H2 emission monitoring and reducing the uncertainty of short-lived H2 climate forcing so as to clearly address H2 emissions for net-zero strategies.
Cooper J, Dubey L, Hawkes A, 2022, The life cycle environmental impacts of negative emission technologies in North America, Sustainable Production and Consumption, Vol: 32, Pages: 880-894, ISSN: 2352-5509
Negative emission technologies (NETs) could play a key role in ensuring net-zero and longer-term net negative emission ambitions are met. However, greenhouse gas emissions (and other pollutants) will occur over the life cycle of a NET and will need to be taken into consideration when developing schemes to roll out their use. We compare five NETs: afforestation/reforestation (AR), enhanced weathering (EW), mangrove restoration (MR), bioenergy and direct air capture with carbon storage (BECCS and DAC), using life cycle assessment to determine their environmental impacts (global warming, freshwater, toxicity etc.). We find that there is a wide range in the environmental impacts estimated across the NETs and the context in which they are used will directly impact which NET has low or high environmental impacts. This is an important aspect to consider when deciding which NET to prioritise in strategies to roll out their use on large scales. If consistent removal of CO2 from the atmosphere is the goal, then AR and MR have the lowest environmental impacts. However, if large and quick CO2 removal is the goal then EW, DAC and BECCS have similar, if not lower, environmental impacts.
Bakkaloglu S, Cooper J, Hawkes A, 2022, Methane emissions along biomethane and biogas supply chains are underestimated, One Earth, Vol: 5, Pages: 724-736, ISSN: 2590-3322
Although natural gas generates lower CO2 emissions, gas extraction, processing, and distribution all release methane, which has a greater global warming potential than CO2. Biomethane and biogas that use organic wastes as a feedstock have emerged as alternatives to natural gas, with lower carbon and methane emissions. However, the extent to which methane is still emitted at various stages along biogas and biomethane supply chains remains unclear. Here, we adopt a Monte Carlo approach to systematically synthesize the distribution of methane emissions at each key biomethane and biogas supply chain stage using data collected from the existing literature. We show that the top 5% of emitters are responsible for 62% of emissions. Methane emissions could be more than two times of greater than previously estimated, with the digestate handling stage responsible for the majority of methane released. To ensure the climate benefits of biomethane and biogas production, effective methane-mitigation strategies must be designed and deployed at each supply chain stage.
Cooper J, Dubey L, Hawkes A, 2022, Life cycle assessment of negative emission technologies for effectiveness in carbon sequestration, 29th CIRP Life Cycle Engineering Conference, Publisher: Elsevier, Pages: 357-361, ISSN: 2212-8271
As climate change and emissions targets tighten, negative emissions technologies (NETs) will play a crucial role in making sure global temperature rises do not exceed Paris Agreement goals. There are a variety of NETs that can be used to abate greenhouse gas (GHG) emissions, but it is uncertain which are more effective, and by how much, as well as what the net GHG removal is as all NETs will emit GHGs and other pollutants throughout their life cycles. We conducted a life cycle assessment (LCA) to compare four NETs: afforestation/reforestation, enhanced weathering, direct air capture and bioenergy with carbon capture and storage. These are compared on their life cycle impacts to climate change, land use change and toxicity (human and terrestrial). We find that the most effective NET is afforestation/reforestation for the environmental impacts considered while enhanced weathering and direct air capture are less effective. However, when the rate of carbon removal is considered, we find that afforestation/reforestation is much slower than the other NETs. Therefore, while it has the lowest impacts to the environment, either long time frames or large-scale implementation is needed for it to match the capacity of direct air capture or bioenergy with carbon capture and storage.
Cooper J, Dubey L, Hawkes A, 2021, Methane detection and quantification in the upstream oil and gas sector: the role of satellites in emissions detection, reconciling and reporting, Environmental Science: Atmospheres, Vol: 2, Pages: 9-23, ISSN: 2634-3606
Oil and gas activities are a major source of methane and in recent years multiple companies have made pledges to cut their emissions of this potent greenhouse gas. Satellites are a promising technology, but their relevance to emissions reconciliation and reporting has not yet been independently established. In this review paper, we assess the capabilities of satellites to determine their role in emissions detection, reconciling and reporting in the upstream section of the oil and gas value chain. In reconciling, satellites have a role in verifying emissions estimated by other technologies, as well as in determining what is causing discrepancies in emission estimates. There are many limitations to satellite usage which need to be addressed before their widescale or routine use by the sector, particularly relating to where they can be used, and high uncertainty associated with their emission estimates. However, where limitations are overcome, satellites could potentially transform the way emissions are reconciled and reported through long-term monitoring, building emission profiles, and tracking whether emission targets are being met. Satellites are valuable tools, not just to the oil and gas sector but to international governments and organisations, as abating methane is crucial for achieving Paris Agreement ambitions.
Cooper J, Balcombe P, Hawkes A, 2021, The quantification of methane emissions and assessment of emissions data for the largest natural gas supply chains, Journal of Cleaner Production, Vol: 320, Pages: 1-10, ISSN: 0959-6526
Methane emitted from natural gas supply chains are a major source of greenhouse gas emissions, but there is uncertainty on the magnitude of emissions, how they vary, and which key factors influence emissions. This study estimates the variation in emissions across the major natural gas supply chains, alongside an estimate of uncertainty which helps identify the areas at the greatest emissions ‘risk’. Based on the data, we estimate that 26.4 Mt CH4 (14.5–48.2 Mt CH4) was emitted by these supply chains in 2017. The risk assessment identified a significant proportion of countries to be at high risk of high emissions. However, there is a large dependency on Tier 1 emission factors, inferring a high degree of uncertainty and a risk of inaccurate emission accounting. When emissions are recalculated omitting Tier 1 data, emissions reduce by 47% to 3.8-fold, downstream and upstream respectively, across regions. More efforts in collecting robust and transparent primary data should be made, particularly in Non-Annex 1 countries, to improve our understanding of methane emissions.
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
Stamford L, Turkmen BA, Cooper J, et al., 2020, Multi-criteria decision analysis for energy policy, ROUTLEDGE HANDBOOK OF ENERGY ECONOMICS, Editors: Soytas, Sari, Publisher: ROUTLEDGE, Pages: 582-614, ISBN: 978-1-138-20825-4
Cooper J, Balcombe P, Hawkes A, 2019, Life cycle environmental impacts of natural gas drivetrains used in UK road freighting and impacts to UK emission targets, Science of the Total Environment, Vol: 674, Pages: 482-493, ISSN: 0048-9697
Using natural gas as a fuel in the road freight sector instead of diesel could cut greenhouse gas and air quality emissions but the switch alone is not enough to meet UK climate targets. A life cycle assessment (LCA) has been conducted comparing natural gas trucks to diesel, biodiesel, dimethyl ether and electric trucks on impacts to climate change, land use change, air quality, human health and resource depletion. This is the first LCA to consider a full suite of environmental impacts and is the first study to estimate what impact natural gas could have on reducing emissions form the UK freight sector. If LNG is used, climate change impacts could be up to 33% lower per km and up to 12% lower per kWh engine output. However, methane emissions will eliminate any benefits if they exceed 1.5–3.5% of throughput for typical fuel consumption. For non-climate impacts, natural gas exhibits lower emissions (11–66%) than diesel for all indicators. Thus, for natural gas climate benefits are modest. However, emissions of CO, methane and particulate matter are over air quality limits set for UK trucks. Of the other options, electric and biodiesel trucks perform best in climate change, but are the worst with respect to land use change (which could have significant impacts on overall climate change benefits), air quality, human toxicity and metals depletion indicators. Natural gas could help reduce the sector's emissions but deeper decarbonization options are required to meet 2030 climate targets, thus the window for beneficial utilisation is short.
Cooper J, Balcombe P, 2019, Life cycle environmental impacts of natural gas drivetrains used in road freighting, Procedia CIRP, Vol: 80, Pages: 334-339, ISSN: 2212-8271
Cooper J, Stamford L, Azapagic A, 2018, Economic viability of UK shale gas and potential impacts on the energy market up to 2030, Applied Energy, ISSN: 0306-2619
Cooper J, Stamford L, Azapagic A, 2017, Social sustainability assessment of shale gas in the UK, Sustainable Production and Consumption, ISSN: 2352-5509
Cooper J, Stamford L, Azapagic A, 2017, Sustainability of UK shale gas in comparison with other electricity options: Current situation and future scenarios., Science of the Total Environment, Vol: 619-620, Pages: 804-814, ISSN: 0048-9697
Many countries are considering exploitation of shale gas but its overall sustainability is currently unclear. Previous studies focused mainly on environmental aspects of shale gas, largely in the US, with scant information on socio-economic aspects. To address this knowledge gap, this paper integrates for the first time environmental, economic and social aspects of shale gas to evaluate its overall sustainability. The focus is on the UK which is on the cusp of developing a shale gas industry. Shale gas is compared to other electricity options for the current situation and future scenarios up to the year 2030 to investigate whether it can contribute towards a more sustainable electricity mix in the UK. The results obtained through multi-criteria decision analysis suggest that, when equal importance is assumed for each of the three sustainability aspects shale gas ranks seventh out of nine electricity options, with wind and solar PV being the best and coal the worst options. However, it outranks biomass and hydropower. Changing the importance of the sustainability aspects widely, the ranking of shale gas ranges between fourth and eighth. For shale gas to become the most sustainable option of those assessed, large improvements would be needed, including a 329-fold reduction in environmental impacts and 16 times higher employment, along with simultaneous large changes (up to 10,000 times) in the importance assigned to each criterion. Similar changes would be needed if it were to be comparable to conventional or liquefied natural gas, biomass, nuclear or hydropower. The results also suggest that a future electricity mix (2030) would be more sustainable with a lower rather than a higher share of shale gas. These results serve to inform UK policy makers, industry and non-governmental organisations. They will also be of interest to other countries considering exploitation of shale gas.
Cooper J, Stamford L, Azapagic A, 2016, Shale Gas: A Review of the Economic, Environmental, and Social Sustainability, Energy Technology, Vol: 4, Pages: 772-792, ISSN: 2194-4288
Cooper J, Stamford L, Azapagic A, 2014, Cover Picture: Environmental Impacts of Shale Gas in the UK: Current Situation and Future Scenarios (Energy Technol. 12/2014), Energy Technology, Vol: 2, Pages: 941-941, ISSN: 2194-4288
Cooper J, Stamford L, Azapagic A, 2014, Environmental Impacts of Shale Gas in the UK: Current Situation and Future Scenarios, Energy Technology, Vol: 2, Pages: 1012-1026, ISSN: 2194-4288
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