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  • Journal article
    Allison J, Bell K, Clarke J, Cowie A, Elsayed A, Flett G, Oluleye G, Hawkes A, Hawker G, Kelly N, de Castro MMM, Sharpe T, Shea A, Strachan P, Tuohy Pet al., 2018,

    Assessing domestic heat storage requirements for energy flexibility over varying timescales

    , Applied Thermal Engineering, Vol: 136, Pages: 602-616, ISSN: 1359-4311

    © 2018 The Authors This paper explores the feasibility of storing heat in an encapsulated store to support thermal load shifting over three timescales: diurnal, weekly and seasonal. A building simulation tool was used to calculate the space heating and hot water demands for four common UK housing types and a range of operating conditions. A custom sizing methodology calculated the capacities of storage required to fully meet the heat demands over the three timescales. Corresponding storage volumes were calculated for a range of heat storage materials deemed suitable for storing heat within a dwelling, either in a tank or as an integral part of the building fabric: hot water, concrete, high-temperature magnetite blocks, and a phase change material. The results indicate that with low temperature heat storage, domestic load shifting is feasible over a few days. Beyond this timescale, the very large storage volumes required make integration in dwellings problematic. Supporting load shifting over 1–2 weeks is feasible with high temperature storage. Retention of heat over periods longer than this is challenging, even with significant levels of insulation. Seasonal storage of heat in an encapsulated store appeared impractical in all cases modelled due to the volume of material required.

  • Journal article
    Jalil Vega FA, Hawkes A, 2018,

    Spatially resolved optimization for studying the role of hydrogen for heat decarbonization pathways

    , ACS Sustainable Chemistry and Engineering, Vol: 6, Pages: 5835-5842, ISSN: 2168-0485

    This paper studies the economic feasibility of installing hydrogen networks for decarbonising heat in urban areas. The study uses the Heat Infrastructure and Technology (HIT) spatially-resolved optimisation model to trade-off energy supply, infrastructure and end-use technology costs for the most important heat-related energy vectors; gas, heat, electricity, and hydrogen. Two model formulations are applied to UK urban area: one with an independent hydrogen network, and one that allows for retrofitting the gas network into hydrogen. Results show that for average hydrogen price projections, cost-effective pathways for heat decarbonisation towards 2050 comprise including heat networks supplied by a combination of district level heat pumps and gas boilers in the domestic and commercial sectors, and hydrogen boilers in the domestic sector. For a low hydrogen price scenario, when retrofitting the gas network into hydrogen, a cost-effective pathway is replacing gas by hydrogen boilers in the commercial sector, and a mixture of hydrogen boilers and heat networks supplied by district level heat pumps, gas, and hydrogen boilers for the domestic sector. Compared to the first modelled year, CO2 emissions reductions of 88% are achieved by 2050. These results build on previous research on the role of hydrogen in cost-effective heat decarbonisation pathways.

  • Journal article
    Oluleye G, Hawkes AD, Allison J, Kelly N, Clarke Jet al., 2018,

    An optimisation study on integrating and incentivising Thermal Energy Storage (TES) in a dwelling energy system

    , Energies, Vol: 11, ISSN: 1996-1073

    In spite of the benefits from thermal energy storage (TES) integration in dwellings, the penetration rate in Europe is 5%. Effective fiscal policies are necessary to accelerate deployment. However, there is currently no direct support for TES in buildings compared to support for electricity storage. This could be due to lack of evidence to support incentivisation. In this study, a novel systematic framework is developed to provide a case in support of TES incentivisation. The model determines the costs, CO2 emissions, dispatch strategy and sizes of technologies, and TES for a domestic user under policy neutral and policy intensive scenarios. The model is applied to different building types in the UK. The model is applied to a case study for a detached dwelling in the UK (floor area of 122 m2), where heat demand is satisfied by a boiler and electricity imported from the grid. Results show that under a policy neutral scenario, integrating a micro-Combined Heat and Power (CHP) reduces the primary energy demand by 11%, CO2 emissions by 21%, but with a 16 year payback. Additional benefits from TES integration can pay for the investment within the first 9 years, reducing to 3.5–6 years when the CO2 levy is accounted for. Under a policy intensive scenario (for example considering the Feed in Tariff (FIT)), primary energy demand and CO2 emissions reduce by 17 and 33% respectively with a 5 year payback. In this case, the additional benefits for TES integration can pay for the investment in TES within the first 2 years. The framework developed is a useful tool is determining the role TES in decarbonising domestic energy systems.

  • Journal article
    Speirs JF, balcombe P, johnson E, martin J, brandon N, hawkes Aet al., 2018,

    A Greener Gas Grid: What Are the Options?

    , Energy Policy, Vol: 118, Pages: 291-297, ISSN: 0301-4215

    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.

  • Journal article
    Crow DJG, Giarola S, Hawkes AD, 2018,

    A dynamic model of global natural gas supply

    , Applied Energy, Vol: 218, Pages: 452-469, ISSN: 0306-2619

    This paper presents the Dynamic Upstream Gas Model (DYNAAMO); a new, global, bottom-up model of natural gas supply. In contrast to most “static” supply-side models, which bracket resources by average cost, DYNAAMO creates a range of dynamic outputs by simulating investment and operating decisions in the upstream gas industry triggered in response to investors’ expectations of future gas prices. Industrial data from thousands of gas fields is analysed and used to build production and expenditure profiles which drive the economics of supply at field level. Using these profiles, a novel methodology for estimating supply curves is developed which incorporates the size, age and operating environment of gas fields, and treats explicitly the fiscal, abandonment, exploration and emissions costs of production. The model is validated using the US shale gas boom in the 2000s as a historic case study. It is found that the modelled market share of supply by field environment replicates the observed trend during the period 2000–2010, and that the model price response during the same period – due to lower capacity margins and the financing of new projects – is consistent with market behaviour.

  • Journal article
    Giarola S, Forte O, Lanzini A, Gandiglio M, Santarelli M, Hawkes Aet al., 2018,

    Techno-economic assessment of biogas-fed solid oxide fuel cell combined heat and power system at industrial scale

    , Applied Energy, Vol: 211, Pages: 689-704, ISSN: 0306-2619

    Wastewater treatment plants (WWTP) are currently very energy and greenhouse gas intensive processes. An important opportunity to reduce both of these quantities is via the use of biogas produced within the treatment process to generate energy. This paper studies the optimal energy and economic performance of a wastewater treatment facility fitted with a solid oxide fuel cell (SOFC) based combined heat and power (CHP) plant. An optimisation framework is formulated and then applied to determine cost, energy and emissions performance of the retrofitted system when compared with conventional alternatives.Results show that present-day capital costs of SOFC technology mean that it does not quite compete with the conventional alternatives. But, it could become interesting if implemented in thermally-optimised WWTP systems. This would increase the SOFC manufacturing volumes and drive a reduction of capital and fixed operating costs.

  • Book chapter
    de Castro REN, Alves RMB, Hawkes A, Nascimento CAOet al., 2018,

    Open Sugarcane Process Simulation Platform

    , Computer Aided Chemical Engineering, Pages: 1819-1824

    Software tools for process simulation and optimization have increasingly been used in industry to design and operate complex, highly interconnected plants. This allows the design of industrial plants to be profitable and to meet quality, safety, environmental and other standards. The aim of this work is to create a platform to simulate industrial sugarcane first generation process. Brazilian sugarcane industry is a well known process with many parameters available from industrial and literature data. The current first generation process seems to have reached the state of art and not great improvements seams to emerge nowadays. However engineering research has dedicated great efforts recently to improve efficiency through the use of industrial and agricultural residues. Most of these studies are related to the use of lignocellulosic material and vinasse. In this context an easy and simple platform has been developed to provide reliable outputs that could provide data for the studies of viability, social and environmental impacts when an additional process are interconnected to the first generation plant. The model has been validated using industrial data in order to attain the most realistic outputs.

  • Book chapter
    Oluleye G, Allison J, Kelly N, Hawkes Aet al., 2018,

    A Multi-period Mixed Integer Linear Program for Assessing the Benefits of Power to Heat Storage in a Dwelling Energy System

    , Editors: Friedl, Klemes, Radl, Varbanov, Wallek, Publisher: ELSEVIER SCIENCE BV, Pages: 1451-1456
  • Conference paper
    Sachs J, Massari C, Hawkes A, Sawodny Oet al., 2018,

    Distributed Optimization for a Cost Efficient Operation of a Network of Island Energy Systems

    , 2nd IEEE Conference on Control Technology and Applications (CCTA), Publisher: IEEE, Pages: 46-53
  • Conference paper
    Garcia Kerdan I, Hawkes AD, Giarola S, 2018,

    Implications of Future Natural Gas Infrastructure on Bioenergy Production, Land Use Change and Related Emissions: A Brazil Case Study

    , 1st SDEWES Latin America

    Due to its low global share of direct energy consumption (3-5%) and greenhouse gas emissions (1-2%), energy systems models (ESM) have unfairly overlooked the implications of technological transitions in the agricultural sector. In fact, if the demand of agrochemicals and land use changes (LUC) due to expansion of bioenergy crops and increasing food demand are considered, the sector is indirectly responsible for up to 30% of global emissions. This paper introduces the Agriculture and Land Use Sector Simulation Module (Ag&LU-SM) which is integrated in a novel ESM, called MUSE, the ModUlar energy systems Simulation Environment. The Ag&LU-SM simulates the investments in agricultural energy technologies through the concept of mechanisation diffusion to meet the demand of sector’s commodities, such as crops, animal and forestry products, as well as the implications due to LUC when arable or forest land is allocated to bioenergy crops. The aim is to study the sector’s dynamics and resource competition between bioenergy and natural gas at a country level. Brazil, one of the major bioenergy producers and with large amounts of oil and natural gas reserves, is used as a case study to study the implications in terms of land use change in two different scenarios. One scenario explores a ten-fold expansion of bioenergy production by 2050, which means a 6% annual growth rate. The second scenario explores the expansion of natural gas production while halving bioenergy production (3% annual growth rate). Results show that, in order to meet the future food and bioenergy demand, the agricultural sector should move from transitional to modern agricultural practices, improve the productivity at the expense of higher energy consumption, invest in efficient agricultural practices to reduce land-related emissions and have the opportunity to liberate crop and pasture land that could be used for dedicated energy crops. Finally, the development of a gas infrastructure coul

  • Book chapter
    Sachs J, Hidayat S, Giarola S, Hawkes Aet al., 2018,

    The role of CCS and biomass-based processes in the refinery sector for different carbon scenarios

    , Editors: Friedl, Klemes, Radl, Varbanov, Wallek, Publisher: ELSEVIER SCIENCE BV, Pages: 1365-1370
  • Book chapter
    Sechi S, Giarola S, Lanzini A, Gandiglio M, Oluleye G, Santarelli M, Hawkes Aet al., 2018,

    An optimization method to estimate the SOFC market in waste water treatment

    , Editors: Friedl, Klemes, Radl, Varbanov, Wallek, Publisher: ELSEVIER SCIENCE BV, Pages: 415-420
  • Book chapter
    Luh S, Budinis S, Schmidt TJ, Hawkes Aet al., 2018,

    Decarbonisation of the Industrial Sector by means of Fuel Switching, Electrification and CCS

    , Editors: Friedl, Klemes, Radl, Varbanov, Wallek, Publisher: ELSEVIER SCIENCE BV, Pages: 1311-1316
  • Conference paper
    Budinis S, Giarola S, Sachs J, Hawkes ADet al., 2017,

    Modelling the impacts of investors' decision making on decarbonisation pathways in industry

    , 10th Annual Meeting of the IAMC, Publisher: IAMC

    The Paris Climate agreement calls for dramatic changes in the energy system. This will be challenging for demand sectors like industry, which is notoriously energy intensive. Although increased efficiency has proven to be suitable options to reduce energy and environmental impacts, stringent regulations on carbon will require this sector to undergo an unprecedented innovation effort, which will go well beyond cost efficiency measures to include the deployment of novel technologies and, most likely, of carbon capture and storage (CCS).This manuscript focuses on the uptake of novel technologies in the industrial sector and the barriers which might prevent or slow down the pace of innovation. Some of these barriers are technological as they depend on the availability and the technology readiness level of a specific technology. Others are instead related to the attitude that investors show towards innovative and the inherent level of risk. Among the many innovation options in the industrial sector, the focus here is on the uptake of the carbon capture and storage technologies.The industrial sector is modelled including the top-energy intensive industries, such as those manufacturing pulp and paper, iron and steel, chemicals and petrochemicals, the non-ferrous metals as well as non-metallic minerals. The simulations are carried out using a novel energy systems model, MUSE, the Modular energy systems Simulation Environment.

  • Journal article
    Balcombe P, Brandon NP, Hawkes AD, 2017,

    Characterising the distribution of methane and carbon dioxide emissions from the natural gas supply chain

    , Journal of Cleaner Production, Vol: 172, Pages: 2019-2032, ISSN: 0959-6526

    Methane and CO2 emissions from the natural gas supply chain have been shown to vary widely butthere is little understanding about the distribution of emissions across supply chain routes,processes, regions and operational practises. This study defines the distribution of total methaneand CO2 emissions from the natural gas supply chain, identifying the contribution from each stageand quantifying the effect of key parameters on emissions. The study uses recent high-resolutionemissions measurements with estimates of parameter distributions to build a probabilistic emissionsmodel for a variety of technological supply chain scenarios. The distribution of emissions resemblesa log-log-logistic distribution for most supply chain scenarios, indicating an extremely heavy tailedskew: median estimates which represent typical facilities are modest at 18 – 24 g CO2 eq./ MJ HHV,but mean estimates which account for the heavy tail are 22 – 107 g CO2 eq./ MJ HHV. To place thesevalues into context, emissions associated with natural gas combustion (e.g. for heat) areapproximately 55 g CO2/ MJ HHV. Thus, some supply chain scenarios are major contributors to totalgreenhouse gas emissions from natural gas. For methane-only emissions, median estimates are 0.8 –2.2% of total methane production, with mean emissions of 1.6 - 5.5%. The heavy tail distribution isthe signature of the disproportionately large emitting equipment known as super-emitters, whichappear at all stages of the supply chain. The study analyses the impact of different technologicaloptions and identifies a set of best technological option (BTO) scenarios. This suggests thatemissions-minimising technology can reduce supply chain emissions significantly, with this studyestimating median emissions of 0.9% of production. However, even with the emissions-minimisingtechnologies, evidence suggests that the influence of the super-emitters remains. Therefore,emissions-minimising technology is only part of the soluti

  • Journal article
    Schmidt O, Gambhir A, Staffell IL, Hawkes A, Nelson J, Few Set 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.

  • Journal article
    Vijay A, Hawkes A, 2017,

    The techno-economics of small-scale residential heating in low carbon futures

    , Energies, Vol: 10, ISSN: 1996-1073

    Existing studies that consider the techno-economics of residential heating systems typically focus on their performance within present-day energy systems. However, the energy system within which these technologies operate will need to change radically if climate change mitigation is to be achieved. This article addresses this problem by modelling small-scale heating techno-economics in the context of significant electricity system decarbonisation. The current electricity market price regime based on short run marginal costs is seen to provide a very weak investment signal for electricity system investors, so an electricity price regime based on long run marginal energy costs is also considered, using a case study of the UK in 2035. The economic case for conventional boilers remains stronger in most dwelling types. The exception to this is for dwellings with high annual heat demand. Sensitivity studies demonstrate the impact of factors such as price of natural gas, carbon intensity of the central grid and thermodynamic performance. Fuel cell micro combined heat and power shows most potential under the long run electricity price regime, and heat pumps under the short run electricity price regime. This difference highlights the importance of future electricity market structure on consumer choice of heating systems in the future.

  • Journal article
    Clark R, Budinis S, Hawkes A, McMartin Det al.,

    Analysis of power production and emission reduction through the use of biogas and carbon capture and storage

    , Computer Aided Chemical Engineering
  • Conference paper
    Sechi S, Giarola S, Lanzini A, Gandiglio M, Oluleye O, Santarelli M, Hawkes Aet al., 2017,

    Techno-economic assessment of the effects of biogas rate fluctuations on industrial applications of solid-oxide fuel cells

    , ESCAPE-27, Publisher: Elsevier, ISSN: 1570-7946

    Wastewater treatment is an energy and greenhouse gas intensive process. An important opportunity to reduce both of these quantities is via the use of biogas in co-generation systems. Solid-oxide fuel cells (SOFCs) are the generator types studied in this work.The feasibility of the retrofitting of a wastewater treatment facility fitted with a SOFC combined heat and power energy provision system is assessed including effects of uncertainties in biogas availability on cost and energy performance. A two-stage stochastic optimization framework is proposed to provide feedback on the energy co-generation system design.Results quantify standard deviations in the biogas rate beyond which the SOFC capacity factor might drop below 80 % and change the optimal size of the modules to install.Keywords: solid-oxide fuel cells, stochastic optimization, wastewater treatment, biogas.

  • Report
    Speirs J, Balcombe P, Johnson E, Martin J, Brandon N, Hawkes Aet al., 2017,

    A Greener Gas Grid: What Are the Options?

    , A greener gas grid: what are the options?
  • Conference paper
    Giarola S, Budinis S, Sachs J, Hawkes ADet al., 2017,

    Long-term decarbonisation scenarios in the industrial sector

    , International Energy Workshop

    Decarbonisation targets will drive every sector in the energy system to rapidly adopt innovativetechnologies to achieve the dramatic emissions reductions required. Among all, sectors like in-dustry, which currently exhibit a very high energy intensity, are likely to undergo major changes.This manuscript focuses on the appraisal of the effects of a CO2tax in the investment and operationdecisions in industry. Within the larger modelling framework typical of an integrated assessmentmodel, the sector is modelled including the top-energy intensive industries, such as those man-ufacturing pulp and paper, iron and steel, chemicals and petrochemicals, the non-ferrous metalsas well as non-metallic minerals. The simulations are carried out using a novel energy systemsmodel, MUSE, the Modular Universal energy systems Simulation Environment model.

  • Conference paper
    Sachs J, Giarola S, Hawkes AD, 2017,

    Agent-based model for energy-related investment decisions in the residential building sector

    , International Energy Workshop, Publisher: International Energy Workshop
  • Journal article
    Jalil Vega F, Hawkes AD, 2017,

    Spatially resolved model for studying decarbonisation pathways for heat supply and infrastructure trade-offs

    , Applied Energy, Vol: 210, Pages: 1051-1072, ISSN: 1872-9118

    Heat decarbonisation is one of the main challenges of energy system decarbonisation. However, existing energy planning models struggle to compare heat decarbonisation approaches because they rarely capture trade-offs between heat supply, end-use technologies and network infrastructure at sufficient spatial resolution. A new optimisation model is presented that addresses this by including trade-offs between gas, electricity, and heat infrastructure, together with related supply and end-use technologies, with high spatial granularity. The model is applied in case studies for the UK. For the case modelled it is shown that electrification of heat is most cost-effective via district level heat pumps that supply heat networks, instead of individual building heat pumps. This is because the cost of reinforcing the electricity grid for installing individual heat pumps does not sufficiently offset heat infrastructure costs. This demonstrates the importance of considering infrastructure trade-offs. When modelling the utilisation of a decarbonised gas, the penetration of heat networks and location of district level heat supply technologies was shown to be dependent on linear heat density and on zone topology. This shows the importance of spatial aspects. Scenario-specific linear heat density thresholds for heat network penetration were identified. For the base case, penetration of high temperature heat networks was over 50% and 60% by 2050 for linear heat densities over 1500 and 2500 kWh/m. For the case when medium heat temperature networks were additionally available, a mix of both networks was observed. Medium temperature heat network penetration was over 20%, 30%, and 40% for linear heat densities of over 1500, 2500, and 3000 kWh/m, while high temperature heat network penetration was over 20% and 30% for linear heat densities of under 2000 and 1500 kWh/m respectively.

  • Conference paper
    Budinis S, Mac Dowell N, Krevor S, Dixon T, Kemper J, Hawkes Aet al., 2017,

    Can carbon capture and storage unlock `unburnable carbon'?

    , 13th International Conference on Greenhouse Gas Control Technologies (GHGT), Publisher: Elsevier Science BV, Pages: 7504-7515, ISSN: 1876-6102

    The concept of ‘unburnable carbon’ emerged in 2011, and stems from the observation that if all known fossil fuel reserves are extracted and converted to CO2(unabated), it would exceed the carbon budget and have a very significant effect on the climate. Therefore, if global warming is to be limited to the COP21 target, some of the known fossil fuel reserves should remain unburnt. Several recent reports have highlighted the scale of the challenge, drawing on scenarios of climate change mitigation and their implications for the projected consumption of fossil fuels. Carbon Capture and Storage (CCS) is a critical and available mitigation opportunity and its contributionto timely and cost-effective decarbonisation of the energy system is widely recognised. However, while some studies have considered the role of CCS in enabling access to more fossil fuels, no detailed analysis on this issue has been undertaken. This paper presents a critical review focusing on the technologies that can be applied to enable access to, or ‘unlock’, fossil fuel reserves in a way that will meet climate targets and mitigate climate change. It also quantifies the impact of CCS in unlocking unburnable carbon in the first and in the second half of the century.

  • Journal article
    Balcombe P, Anderson K, Speirs J, Brandon N, Hawkes Aet 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

  • Report
    Budinis S, Krevor S, Mac Dowell N, Brandon N, Hawkes Aet al., 2016,

    Can technology unlock unburnable carbon?

    In 2015, the Conference Of the Parties in Paris (COP21) reached a universal agreement on climate change with the aim of limiting global warming to below 2 °C. In order to stay below 2 °C, the total amount of carbon dioxide (CO2) released, or ‘carbon budget’ must be less than 1,000 gigatonnes (Gt) of CO2. At the current emission rate, this budget will be eroded within the next thirty years. Meeting this target on a global scale is challenging and will require prompt and effective climate change mitigation action.The concept of ‘unburnable carbon’ emerged in 2011, and stems from theobservation that if all known fossil fuel reserves are extracted and converted to CO2 (unabated), it would exceed the carbon budget and have a very significant effect on the climate. Therefore, if global warming is to be limited to the COP21 target, some of the known fossil fuel reserves should remain unburnt.Several recent reports have highlighted the scale of the challenge, drawing on scenarios of climate change mitigation and their implications for the projected consumption of fossil fuels. Carbon capture and storage (CCS) is a critical and available mitigation opportunity that is often overlooked. The positive contribution of CCS technology to timely and cost-effective decarbonisation of the energy system is widely recognised. However, while some studies have considered the role of CCS in enabling access to more fossil fuels, no detailed analysis on this issue has been undertaken.This White Paper presents a critical review focusing on the technologies that can be applied to enable access to, or ‘unlock’, fossil fuel reserves in a way that will meet climate targets and mitigate climate change.The paper includes an introduction to the key issues of carbon budgets and fossil fuel reserves, a detailed analysis of the current status of CCS technology, as well as a synthesis of a multi-model comparison study on global climate change mitigation strat

  • Conference paper
    Crow D, Giarola S, Hawkes AD, 2016,

    Modelling imperfect foresight in investment decisions in the upstream gas industry

    , Energy Systems Conference
  • Report
    Balcombe P, Anderson K, Speirs J, Brandon N, Hawkes Aet al., 2015,

    Methane and CO2 emissions from the natural gas supply chain: an evidence assessment

    , Publisher: Sustainable Gas Institute
  • Book chapter
    Hawkes AD,

    Techno-Economic Assessment of Small and Micro-CHP Systems

    , Small- and micro-combined heat and power systems, Editors: Beith, Publisher: Woodhead

    This chapter provides an introduction to the economic benefits that small scale and micro-CHP systems can provide, and goes on to illustrate a specific techno-economic modelling method for analysis of CHP systems. Beginning with a brief review of how, why, and where CHP and decentralised energy systems can provide economic value, it then discusses the sometimes ill-defined concept of techno-economics, and the variety of modelling techniques that underpin it. An optimisation method designed to examine the technical and site characteristics that can lead to commercially successful CHP is then presented, followed by its application to study the case of residential micro-CHP in the United Kingdom. The results of this analysis demonstrate that the heat-to-power ratio of the micro-CHP prime mover is the key technical characteristic that determines economic and environmental performance, in addition to site specific attributes such as onsite electricity demand and the presence of significant thermal demand. Going forward, the emerging tension between CHP and heat pumps for space and water heating applications is touched on in the context of long term stringent emissions reduction targets.

  • Book chapter
    Hawkes AD, Staffell I, Barton J, Bergman N, Brandon NPet al.,


    , Making the Transition to a Secure and Low-Carbon Energy System - Synthesis Report, Editors: Skea, London, UK, Publisher: UKERC

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