10 results found
Aaboud M, Aad G, Abbott B, et al., 2019, Measurement of jet-substructure observables in top quark, W boson and light jet production in proton-proton collisions at root s=13 TeV with the ATLAS detector, The Journal of High Energy Physics, Vol: 33, Pages: 1-47, ISSN: 1029-8479
A measurement of jet substructure observables is presented using data collected in 2016 by the ATLAS experiment at the LHC with proton-proton collisions at 𝑠√ = 13 TeV. Large-radius jets groomed with the trimming and soft-drop algorithms are studied. Dedicated event selections are used to study jets produced by light quarks or gluons, and hadronically decaying top quarks and W bosons. The observables measured are sensitive to substructure, and therefore are typically used for tagging large-radius jets from boosted massive particles. These include the energy correlation functions and the N-subjettiness variables. The number of subjets and the Les Houches angularity are also considered. The distributions of the substructure variables, corrected for detector effects, are compared to the predictions of various Monte Carlo event generators. They are also compared between the large-radius jets originating from light quarks or gluons, and hadronically decaying top quarks and W bosons.
Hanna RF, Gazis E, Edge J, et al., 2018, Unlocking the potential of Energy Systems Integration: An Energy Futures Lab Briefing Paper, Publisher: Energy Futures Lab
Energy Systems Integration’s (ESI) underlying concept is the coordination, and integration, of energy generation and use at local, regional and national levels. This relates to all aspects of energy from production and conversion to delivery and end use. Building such a system is potentially a cost-effective way to decarbonise our energy sector and produce a more reliable and resilient system. This Briefing Paper investigates how the UK can link heat, transport, electricity and other energy vectors into one interconnected ecosystem. It lays out the immense opportunities of having an interconnected and integrated energy ecosystem and the technologies that could make it a reality. Among these is enabling variable renewable electricity and lower-carbon fuels to provide energy services traditionally provided by higher-carbon sources. This could be realised through a more resilient system incorporating greater flexibility and more diverse energy sources.
Rhodes A, Gazis E, Gross RJK, 2017, Is the UK facing an electricity security crisis? An Energy Futures Lab briefing paper., Publisher: Imperial College Energy Futures Lab
Britain’s media outlets have carried manystories about an ‘energy gap’, claimed to havearisen because the UK has failed to buildenough power stations to meet demand. Talkof upcoming ‘blackouts’, with the UK unable toproduce enough electricity to keep the lights on,is commonplace, with several hundred articlespublished in mainstream UK newspapers onthis topic over the last decade. These claimshave always been contested by the governmentand electricity system operator, National Grid,but the debate continues. This Briefing Paper,produced by Energy Futures Lab, reviews theevidence to determine whether the UK will facean electricity security crisis in the coming years.
Mawhood RK, Gazis E, de Jong S, et al., 2016, Production pathways for renewable jet fuel: a review of commercialisation status and future prospects, Biofuels, Bioproducts and Biorefining, Vol: 10, Pages: 462-484, ISSN: 1932-1031
Aviation is responsible for an increasing share of anthropogenic CO2 emissions.Decarbonisation to 2050 is expected to rely on renewable jet fuel (RJF) derived frombiomass, but this represents a radical departure from the existing regime of petroleumbasedfuels. Increased market deployment will require significant cost reductions, alongsideadaptation of existing supply chains and infrastructure.This article maps development and manufacturing efforts for six RJF production pathwaysexpected to reach commercialisation in the next 5-10 years. A Rapid Evidence Assessmentwas conducted to evaluate the technological and commercial maturity of each pathway andprogress towards international certification, using the Commercial Aviation Alternative FuelsInitiative’s Fuel Readiness Level (FRL) framework. Planned and operational facilities havebeen catalogued alongside partnerships with the aviation industry. Policy and economicfactors likely to affect future development and deployment are considered.Hydroprocessed Esters and Fatty Acids (FRL 9) is the most developed pathway. It is ASTMcertified, has fuelled the majority of RJF flights to date, and is produced at threecommercial-scale facilities. Fischer-Tropsch derived fuels are moving towards the start-up offirst commercial facilities (FRL 7-8), although widespread deployment seems unlikely undercurrent market conditions. The Direct Sugars to Hydrocarbons conversion pathway (FRL 5-7)is being championed by Amyris and Total in Brazil, but has yet to be demonstrated at scale.Other pathways are in the demonstration and pilot phases (FRL 4-6).Despite growing interest in RJF, demand and production volumes remain negligible.Development of supportive policy is likely to be critical to future deployment.
Mawhood RK, Gazis E, Hoefnagels R, et al., 2015, Technological and commercial maturity of aviation biofuels: Emerging options to produce jet from lignocellulosic biomass, 14th International Conference on Sustainable Energy Technologies (SET 2015)
The aviation sector is responsible for an increasing share of anthropogenic CO2 emissions. Wider adoption of aviation biofuels (biojet) is imperative for the reduction of greenhouse-gas emissions, however it represents a radical departure from the existing technological regime of petroleum-based fuels. Further market deployment will require significant techno-economic breakthroughs, as well as adaptation of the existing supply chains and infrastructure.Although a large number of technologies which have the capability to produce such fuels are being developed, many of these are unlikely to be suitable for EU-based production in the short-term. Biojet production pathways vary considerably in terms of their techno-economic features, with the most highly developed being in the very early stages of commercialisation.In this article, the authors map current development and manufacturing efforts within five emerging biojet technological pathways. The research draws upon a comprehensive review of the international academic and grey literature in order to characterise the pathways according to their technological and commercial maturity, as well as progress towards international certification.By implementing the Fuel Readiness Level (FRL) methodology, the authors provide insights regarding not only the current status of the biojet sector, but also potential opportunities for the short-term development of supply chains in the EU.
Gazis E, Candelise C, Winskel M, 2013, Cost Leadership or Diversification? Assessing the Business Strategies of PV Manufacturers Using Case Studies from the USA and the UK, 28th European Photovoltaic Solar Energy Conference and Exhibition
The recent explosive growth of the PV sector combined with the multiple technological advancements have allowed for extensive experimentation in terms of applications and business models. This paper follows on a previous market assessment and offers a mapping of the various business strategies adopted by PV firms. It investigates real case-studies to analyse the benefits and dangers related to diversification through product and market differentiation. Finally it provides insights for the growth potential of such firms taking into consideration not only the techno-economic characteristics that are intrinsic to each one, but also the wider socioeconomic environment. The analysis combines literature research with original empirical evidence gathered using interviews with PV experts and comparative firm-level case studies. It then draws upon innovation studies, technological transitions and business literature to provide a novel analytical framework for the understanding of the factors facilitating or hindering the successful commercialisation of innovative PV applications. This work is part of the EPSRC’s Supergen PV21 Consortium (PV Materials for the 21st Century) and as such it draws upon leading expertise in TF PV technologies.
Karaiskakis AN, Gazis E, Harrison G, 2013, Energy and Carbon Analysis of Photovoltaic Systems in the UK, 28th European Photovoltaic Solar Energy Conference and Exhibition
Energy and carbon audit is a valuable environmental tool based on the Life Cycle Assessment (LCA) framework and it is used in this study to evaluate the energy and carbon equivalent footprint of several PV technologies, throughout their life cycle steps, in a range of installation systems (façade, slanted, flat integrated or free standing) and mounting types (on roof and open ground installations). The research takes into consideration UK’s specific conditions such as electricity mix, transportation, insolation levels etc. and provides a holistic view of photovoltaic (PV) technologies in the country. Case studies of 1kWh and 500 kWh for on roof and open ground installations respectively are conducted. The Cadmium Teluride (CdTe) PV technology is the one that demonstrates the best environmental behaviour even from renewable technologies which rely on more advantageous natural energy sources in the UK. In terms of the environmental indicators, the slanted integrated mounted installation CdTe PV system in Plymouth has the most competitive values, GHG (greenhouse gas) emissions indicator of 23 gCO2eq/kWh, EPBT (energy payback time) of 14.8 months and GHG payback time of 16.8 months.
Gazis E, Candelise C, Winskel M, 2012, The status and prospects of thin-film PV as an emerging technology system, EU Photovoltaic and Solar Energy Conference, 27th PVSEC
Photovoltaics (PV) are currently the prevailing solar energy harvesting technology, and integration of such systems in the power generation mix has been promoted by several governments through policy intervention. Thin film (TF) technologies in particular are considered to have the potential for low cost manufacturing and diverse applications beyond the conventional flat-plate modules. However, future development of the TF PV sector will depend not only on intrinsic factors including technological advances and market characteristics, but also on the interaction of the sector with the incumbent power regimes and the pressures from the energy landscape. This paper provides a summary of the ongoing work on a market assessment and an innovation systems-based analysis of TF PV technologies, with particular focus on product differentiation for innovative applications. It also offers a novel framework for the analysis and the understanding of the potential and the barriers for TF innovation within current and evolving PV and energy markets, so helping to inform policy decisions on TF innovation and niche market management. This work is part of the EPSRC’s Supergen PV21 Consortium (PV Materials for the 21st Century) and as such it draws upon leading expertise in TF PV technologies
Gazis E, Candelise C, Winskel M, 2012, Thin Film PV technologies innovation potential and market positioning, 8th Photovoltaic Science, Applications and Technology Conference (PVSAT - 8)
Gazis E, Harrison G, 2011, Life cycle energy and carbon analysis of domestic combined heat and power generators, Institute of Electrical and Electronics Engineers (IEEE) PowerTech, Publisher: IEEE
Micro Combined Heat and Power (micro-CHP) generatorscombine the benefits of the high-efficiency cogenerationtechnology and microgeneration and is being promoted as ameans of lowering greenhouse gas emissions by decentralizingthe power network. Life Cycle Assessment of energy systemsis becoming a part of decision making in the energy industry,helping manufacturers promote their low carbon devices, andconsumers choose the most environmentally friendly options.This report summarizes a preliminary life-cycle energy andcarbon analysis of a wall-hung gas-powered domestic micro-CHPdevice that is commercially available across Europe. Combininga very efficient condensing boiler with a Stirling engine, thedevice can deliver enough heat to cover the needs of a typicalhousehold (up to 24kW) while generating power (up to 1kW)that can be used locally or sold to the grid. Assuming anannual heat production of 20 MWh, the study has calculatedthe total embodied energy and carbon emissions over a 15 yearsoperational lifetime at 1606 GJ and 90 tonnes of CO2 respectively.Assuming that such a micro CHP device replaces the mostefficient gas-powered condensing boiler for domestic heat production,and the power generated substitutes electricity fromthe grid, the potential energy and carbon savings are around5000 MJ/year and 530 kg CO2/year respectively. This implies apayback period of the embodied energy and carbon at 1.32 - 2.32and 0.75 - 1.35 years respectively.Apart from the embodied energy and carbon and the respectivesavings, additional key outcomes of the study are the evaluationof the energy intensive phases of the device’s life cycle and theexploration of potential improvements.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.