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  • CONFERENCE PAPER
    Abolghasemi M, Piggott MD, Spinneken J, Vire A, Cotter CJ, Crammond Set al.,

    Simulating tidal turbines with mesh optimisation and RANS turbulence models

    , 2015 European Wave and Tidal Energy Conference
  • CONFERENCE PAPER
    Acha S, van Dam KH, Keirstead J, Shah Net al.,

    Integrated modelling of agent-based electric vehicles into optimal power flow studies

    , Frankfurt, Germany
  • JOURNAL ARTICLE
    Avdis A, Jacobs CT, Hill J, Piggott MD, Gorman GJet al.,

    Shoreline and Bathymetry Approximation in Mesh Generation for Tidal Renewable Simulations

    Due to the fractal nature of the domain geometry in geophysical flowsimulations, a completely accurate description of the domain in terms of acomputational mesh is frequently deemed infeasible. Shoreline and bathymetrysimplification methods are used to remove small scale details in the geometry,particularly in areas away from the region of interest. To that end, a novelmethod for shoreline and bathymetry simplification is presented. Existingshoreline simplification methods typically remove points if the resultantgeometry satisfies particular geometric criteria. Bathymetry is usuallysimplified using traditional filtering techniques, that remove unwanted Fouriermodes. Principal Component Analysis (PCA) has been used in other fields toisolate small-scale structures from larger scale coherent features in a robustway, underpinned by a rigorous but simple mathematical framework. Here wepresent a method based on principal component analysis aimed towardssimplification of shorelines and bathymetry. We present the algorithm in detailand show simplified shorelines and bathymetry in the wider region around theNorth Sea. Finally, the methods are used in the context of unstructured meshgeneration aimed at tidal resource assessment simulations in the coastalregions around the UK.

  • JOURNAL ARTICLE
    Few SPM, Gambhir A, Napp T, Hawkes A, Mangeon S, Bernie D, Lowe Jet al.,

    The impact of shale gas on the cost and feasibility of meeting climate targets - a global energy system model analysis and an exploration of uncertainties

    , Energies, ISSN: 1996-1073

    There exists considerable uncertainty over both shaleand conventional gas resource availability and extraction costs, as well as the fugitive methane emissions associated with shale gas extractionand its possible role in mitigating climate change. This study uses a multi-region energy system model, TIAM (TIMES Integrated Assessment Model),to consider the impact of a range of conventional and shale gas cost and availability assessments on mitigation scenariosaimed at achieving a limit to global warming of below 2°C in 2100, with a 50% likelihood. When adding shale gas to the global energy mix, the reduction to the global energy system cost is relatively small (up to0.4%), and the mitigation cost increases by 1-3% under all cost assumptions. The impact of a “dash for shale gas”, of unavailability of carbon capture and storage, of increased barriers to investment in low carbon technologies, and of higher than expectedleakage rates, are also considered;andare each found to have the potential to increase the cost and reduce feasibility of meeting globaltemperature goals. We concludethat the extraction of shale gas is not likely to significantly reduce the effort required to mitigate climate change under globallycoordinatedaction, but could increase required mitigation effort if not handled sufficiently carefully.

  • JOURNAL ARTICLE
    Funke SW, Kramer SC, Piggott MD,

    Design optimisation and resource assessment for tidal-stream renewable energy farms using a new continuous turbine approach

    , Renewable Energy, ISSN: 1879-0682

    This paper presents a new approach for optimising the design of tidal stream turbine farms. In this approach, the turbine farm is represented by a turbine density function that specifies the number of turbines per unit area and an associated continuous locally-enhanced bottom friction field. The farm design question is formulated as a mathematical optimisation problem constrained by the shallow water equations and solved with efficient, gradient-based optimisation methods. The resulting method is accurate, computationally efficient, allows complex installation constraints, and supports different goal quantities such as to maximise power or profit. The outputs of the optimisation are the optimal number of turbines, their location within the farm, the overall farm profit, the farm's power extraction, and the installation cost.We demonstrate the capabilities of the method on a validated numerical model of the Pentland Firth, Scotland. We optimise the design of four tidal farms simultaneously, as well as individually, and study how farms in close proximity may impact upon one another.

  • JOURNAL ARTICLE
    Goode AE, Hine NDM, Chen S, Bergin SD, Shaffer MSP, Ryan MP, Haynes PD, Porter AE, McComb DWet al.,

    Mapping functional groups on oxidised multi-walled carbon nanotubes at the nanometre scale

    , Chemical Communications, ISSN: 1364-548X
  • CONFERENCE PAPER
    Green RJ, Staffell I,

    Storage in the electricity market

    , International Ruhr Energy Conference 2015
  • JOURNAL ARTICLE
    Green RJ, Staffell IL,

    “Prosumage” and the British electricity market

    , Economics of Energy and Environmental Policy, ISSN: 2160-5882

    Domestic electricity consumers with PV panels have become known as “prosumers”; some of them also have energy storage and we have named the combination “prosumage”. The challenges of renewable intermittency could be offset by storing power, and many engineering studies consider the role and value of storage which is properly integrated into the ‘smart grid’. Such a system with holistic optimal control may fail to materialise for regulatory, economic, or behavioural reasons. We therefore model the impact of naïve prosumage: households which use storage only to maximise self-consumption of PV, with no consideration of the wider system. We find it is neither economicfor arbitrage nor particularly beneficial for shaving peaks and filling troughs in national net demand. The extreme case of renewable self-sufficiency, becoming completely independent of the grid, is still prohibitively expensive in Britain and Germany, and even in a country like Spain with a much better solar resource.

  • CONFERENCE PAPER
    Heuberger CF, Staffell I, Shah N, Mac Dowell Net al.,

    Levelised Value of Technology - A Systemic Approach to Technology Valuation

    , 26th European Symposium on Computer Aided Process Engineering - ESCAPE 26
  • JOURNAL ARTICLE
    Kline KL, Msangi S, Dale VH, Woods J, Souza GM, Osseweijer P, Clancy JS, Hilbert JA, Mugera HK, McDonnell PC, Johnson FXet al.,

    Reconciling biofuels and food security: priorities for action

    , Global Change Biology Bioenergy, ISSN: 1757-1693

    Addressing the challenges of understanding and managing complex interactions among food security, biofuels, and resource management requires a focus on specific contextual problems and opportunities. The United Nations’ 2030 Sustainable Development Goals prioritize food and energy security; bioenergy plays an important role in achieving both goals. Effective food security programs begin by clearly defining the problem and asking, “What can be done to effectively assist people at high risk?” Headlines and cartoons that blame biofuels for food insecurity may reflect good intentions but mislead the public and policy makers because they obscure the main drivers of local food insecurity and ignore opportunities for biofuels to contribute to solutions. Applying sustainability guidelines to bioenergy will help achieve near- and long- term goals to eradicate hunger. Priorities for achieving successful synergies between bioenergy and food security include (1) clarifying communications with clear and consistent terms, (2) recognizing that food and bioenergy need not compete for land and instead, need to be integrated with improved resource management, (3) investing in innovations to build capacity and infrastructure such as rural agricultural extension and technology, (4) promoting stable prices that incentivize local production, (5) adopting flex crops that can provide food along with other products and services to society, and (6) engaging stakeholders in identifying and assessing specific opportunities for biofuels to improve food security. Systematic monitoring and analysis to support adaptive management and continual improvement are essential elements to build synergies and help society equitably meet growing demands for both food and energy.

  • CONFERENCE PAPER
    Mechleri E, fennell P, Mac Dowell N,

    Flexible operation strategies for coal- and gas-CCS power stations under the UK and USA markets

    , 13th Greenhouse Gas Control Technologies (GHGT) conference
  • CONFERENCE PAPER
    Mechleri E, rivotti P, mac Dowell N, thornhill Net al.,

    Flexibility issues and controllability analysis of a post-combustion CO2 capture plant integrated with a natural gas power plant

    , 8th Trondheim Conference on CO2 Capture, Transport and Storage (TCCS-8)
  • JOURNAL ARTICLE
    Balcombe P, Anderson K, Speirs J, Brandon N, Hawkes Aet al., 2017,

    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
  • JOURNAL ARTICLE
    Baran D, Ashraf RS, Hanifi DA, Abdelsamie M, Gasparini N, Röhr JA, Holliday S, Wadsworth A, Lockett S, Neophytou M, Emmott CJ, Nelson J, Brabec CJ, Amassian A, Salleo A, Kirchartz T, Durrant JR, McCulloch Iet al., 2017,

    Reducing the efficiency-stability-cost gap of organic photovoltaics with highly efficient and stable small molecule acceptor ternary solar cells.

    , Nat Mater, Vol: 16, Pages: 363-369, ISSN: 1476-1122

    Technological deployment of organic photovoltaic modules requires improvements in device light-conversion efficiency and stability while keeping material costs low. Here we demonstrate highly efficient and stable solar cells using a ternary approach, wherein two non-fullerene acceptors are combined with both a scalable and affordable donor polymer, poly(3-hexylthiophene) (P3HT), and a high-efficiency, low-bandgap polymer in a single-layer bulk-heterojunction device. The addition of a strongly absorbing small molecule acceptor into a P3HT-based non-fullerene blend increases the device efficiency up to 7.7 ± 0.1% without any solvent additives. The improvement is assigned to changes in microstructure that reduce charge recombination and increase the photovoltage, and to improved light harvesting across the visible region. The stability of P3HT-based devices in ambient conditions is also significantly improved relative to polymer:fullerene devices. Combined with a low-bandgap donor polymer (PBDTTT-EFT, also known as PCE10), the two mixed acceptors also lead to solar cells with 11.0 ± 0.4% efficiency and a high open-circuit voltage of 1.03 ± 0.01 V.

  • JOURNAL ARTICLE
    Bertei A, Tariq F, Yufit V, Ruiz-Trejo E, Brandon NPet al., 2017,

    Guidelines for the Rational Design and Engineering of 3D Manufactured Solid Oxide Fuel Cell Composite Electrodes

    , Journal of The Electrochemical Society, Vol: 164, Pages: F89-F98, ISSN: 0013-4651
  • JOURNAL ARTICLE
    Bhave A, Taylor RHS, Fennell P, Livingston WR, Shah N, Dowell NM, Dennis J, Kraft M, Pourkashanian M, Insa M, Jones J, Burdett N, Bauen A, Beal C, Smallbone A, Akroyd Jet al., 2017,

    Screening and techno-economic assessment of biomass-based power generation with CCS technologies to meet 2050 CO<inf>2</inf> targets

    , Applied Energy, Vol: 190, Pages: 481-489, ISSN: 0306-2619

    © 2016 Elsevier LtdBiomass-based power generation combined with CO2 capture and storage (Biopower CCS) currently represents one of the few practical and economic means of removing large quantities of CO2 from the atmosphere, and the only approach that involves the generation of electricity at the same time. We present the results of the Techno-Economic Study of Biomass to Power with CO2 capture (TESBiC) project, that entailed desk-based review and analysis, process engineering, optimisation as well as primary data collection from some of the leading pilot demonstration plants. From the perspective of being able to deploy Biopower CCS by 2050, twenty-eight Biopower CCS technology combinations involving combustion or gasification of biomass (either dedicated or co-fired with coal) together with pre-, oxy- or post-combustion CO2 capture were identified and assessed. In addition to the capital and operating costs, techno-economic characteristics such as electrical efficiencies (LHV% basis), Levelised Cost of Electricity (LCOE), costs of CO2 captured and CO2 avoided were modelled over time assuming technology improvements from today to 2050. Many of the Biopower CCS technologies gave relatively similar techno-economic results when analysed at the same scale, with the plant scale (MWe) observed to be the principal driver of CAPEX (£/MWe) and the cofiring % (i.e. the weighted feedstock cost) a key driver of LCOE. The data collected during the TESBiC project also highlighted the lack of financial incentives for generation of electricity with negative CO2 emissions.

  • JOURNAL ARTICLE
    Biton M, Yufit V, Tariq F, Kishimoto M, Brandon Net al., 2017,

    Enhanced Imaging of Lithium Ion Battery Electrode Materials

    , Journal of The Electrochemical Society, Vol: 164, Pages: A6032-A6038, ISSN: 0013-4651
  • JOURNAL ARTICLE
    Chakrabarti B, Nir D, Yufit V, Tariq F, Rubio-Garcia J, Maher R, Kucernak A, Aravind PV, Brandon Net al., 2017,

    Performance Enhancement of Reduced Graphene Oxide-Modified Carbon Electrodes for Vanadium Redox-Flow Systems

    , ChemElectroChem, Vol: 4, Pages: 194-200

    © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.Reduced graphene oxide (rGO) suspended in an N,N′-dimethylformamide (DMF) solvent underwent electrophoretic deposition (EPD) on carbon paper (CP) electrodes. X-ray computed micro-tomography (XMT) indicates a 24 % increase in the specific surface area of CP modified with rGO in comparison to the untreated sample. Furthermore, XMT confirms that the deposition also penetrates into the substrate. Raman analysis shows that the rGO deposited is more amorphous than the CP electrode. A significant reduction in charge-transfer resistance of the VO2+/VO2+ reaction is also observed (from impedance measurements) in modified samples in comparison to untreated CP electrodes.

  • JOURNAL ARTICLE
    Chen Z, Wang X, Brandon N, Atkinson Aet al., 2017,

    Analysis of spherical indentation of porous ceramic films

    , JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, Vol: 37, Pages: 1031-1038, ISSN: 0955-2219
  • JOURNAL ARTICLE
    Daina N, Sivakumar A, Polak JW, 2017,

    Modelling electric vehicles use: a survey on the methods

    , RENEWABLE & SUSTAINABLE ENERGY REVIEWS, Vol: 68, Pages: 447-460, ISSN: 1364-0321
  • JOURNAL ARTICLE
    Gambhir A, Drouet L, McCollum D, Napp T, Bernie D, Hawkes A, Fricko O, Havlik P, Riahi K, Bosetti V, Lowe Jet al., 2017,

    Assessing the Feasibility of Global Long-Term Mitigation Scenarios

    , ENERGIES, Vol: 10, ISSN: 1996-1073
  • REPORT
    Heptonstall PJ, Gross R, Steiner F, 2017,

    The costs and impacts of intermittency - 2016 update

    , London, Publisher: UK Energy Research Centre
  • REPORT
    Heptonstall PJ, Gross R, Steiner F, 2017,

    The costs and impacts of intermittency - 2016 update

    , Publisher: UK Energy Research Centre
  • JOURNAL ARTICLE
    Kolster C, Mechleri E, Krevor S, Mac Dowell Net al., 2017,

    The role of CO<inf>2</inf> purification and transport networks in carbon capture and storage cost reduction

    , International Journal of Greenhouse Gas Control, Vol: 58, Pages: 127-141, ISSN: 1750-5836

    © 2017 Elsevier LtdA number of Carbon Capture and Storage projects (CCS) are under way around the world, but the technology's high capital and operational costs act as a disincentive to large-scale deployment. In the case of both oxy-combustion and post-combustion CO2 capture, the CO2 compression and purification units (CO2CPU) are vital, but costly, process elements needed to bring the raw CO2 product to a quality that is adequate for transport and storage. Four variants of the CO2CPU were modelled in Aspen HYSYS each of which provide different CO2 product purities at different capital and operating costs. For each unit, a price of CO2 is calculated by assuming that it is an independent entity in which to invest and the internal rate of return (IRR) must be greater or equal to the minimum rate of return on investment. In this study, we test the hypothesis that, owing to the fact that CO2 will likely be transported in multi-source networks, not all CO2 streams will need to be of high purity, and that it may be possible to combine several sources of varying purity to obtain an end-product that is suitable for storage. We find that, when considering study generated costs for an example network in the UK, optimally combining these different sources into one multi-source transport network subject to a minimum CO2 purity of 96% can reduce the price of captured CO2 by 17%.

  • CONFERENCE PAPER
    Latinopoulos C, Sivakumar A, Polak JW, 2017,

    Modeling electric vehicle charging behaviour: What is the relationship between charging location, driving distance and range anxiety?

    , Annual Meeting of the Transportation Research Board

    For parking operators and charging service providers it is critical to understand the factors that influence the demand for charging electric vehicles away from home. This information will not only help them to better anticipate the impact on the power grid, but also to develop revenue maximizing demand response strategies. Recent studies suggest that observable and unobservable attributes of travel demand affect the location and the frequency of charging events. Nevertheless, it is unlikely that there is a simple one way causality in the relationship, since the distinctive characteristics of electric vehicles might also lead to transformations in travel behaviour. In order to examine these ambiguous interrelationships we develop two models: a binary logistic regression for home charging vs out-of-home charging and an ordered logit regression for the daily distance driven with an electric vehicle. Attitudes and perceptions of individuals towards range constraints are indirectly captured with latent constructs like schedule flexibility or mobility necessity. The data used for the analysis were collected through the administration of an online survey to electric vehicle drivers in the UK and Ireland. Results show that there is an intrinsic link between charging and travel behaviour with potential implications both in a strategic and an operational level.

  • JOURNAL ARTICLE
    Liu X, Wu B, Brandon N, Wang Qet al., 2017,

    Tough Ionogel-in-Mask Hybrid Gel Electrolytes in Supercapacitors with Durable Pressure and Thermal Tolerances

    , Energy Technology, Vol: 5, Pages: 220-224, ISSN: 2194-4288

    © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimA primary challenge of gel electrolytes in development of flexible and wearable devices is their weak mechanical performances, including their compressive stress, tensile strength, and puncture resistance. Here we prepare an ionogel-mask hybrid gel electrolyte, which successfully achieves synergic advantages of the high mechanical strength of the mask substance and the superior electrochemical and thermal characteristics of the ionogel. The fabricated supercapacitor can maintain a relatively stable capacitive performance even under a high pressure of 3236 kPa. Meanwhile, with the good thermal stability of the composite gel electrolyte, the solid-state supercapacitor can be operated at high temperatures ranging from 25 °C to 200 °C. The ionogel-mask hybrid gel can be superior tough gel electrolyte for solid-state flexible supercapacitors with durable advantages in both high temperatures and pressures.

  • JOURNAL ARTICLE
    Mechleri E, Brown S, Fennell PS, Mac Dowell Net al., 2017,

    CO<inf>2</inf> capture and storage (CCS) cost reduction via infrastructure right-sizing

    , Chemical Engineering Research and Design, Vol: 119, Pages: 130-139, ISSN: 0263-8762

    © 2017 Institution of Chemical EngineersCarbon capture and storage (CCS) will be a critical component of a portfolio of low-carbon energy technologies required to combat climate change (IEA-GHG, 2013). As such, an extensive transportation infrastructure will be required to transport captured CO2 from different sources to the available sinks. Several studies in the literature suggest that shared oversized pipeline networks may be the most efficient long term option compared to single source to sink pipelines, based on increased CCS deployment over the years and therefore increased CO2 flowrate to the transport network. However, what is neglected in this vision is that the deployment of intermittent renewable energy tends to displace thermal power generation. This directly reduces the amount of fossil fuel burned, CO2 produced, captured and transported through the network. This paper presents an optimisation methodology to “right-size” CO2 transport infrastructure, explicitly accounting for the transient flow of CO2 arising from the co-deployment of intermittent renewable energy generators. By application of this methodology, we demonstrate that capital cost reductions of up to 28% are possible relative to a business-as-usual design case.

  • JOURNAL ARTICLE
    Mechleri E, Fennell PS, Dowell NM, 2017,

    Optimisation and evaluation of flexible operation strategies for coal- and gas-CCS power stations with a multi-period design approach

    , International Journal of Greenhouse Gas Control, Vol: 59, Pages: 24-39, ISSN: 1750-5836

    © 2017 Elsevier LtdThermal power plants are increasingly required to balance power grids by compensating for the intermittent electricity supply from renewable energy resources. As CO2 capture and storage is integrated with both coal- and gas-fired power plants, it is vital that the emission mitigation technology does not compromise their ability to provide this high-value service. Therefore, developing optimal process operation strategies is vital to maximise both the value provided by and the profitability of these important assets. In this work, we present models of coal- and gas-fired power plants, integrated with a post-combustion CO2 capture process using a 30 wt% monoethanolamine (MEA) solvent. With the aim to decoupling the power and capture plants in order to facilitate profit maximising behaviour, a multi-period dynamic optimisation problem was formulated and solved using these models. Four distinct scenarios were evaluated: load following, solvent storage, exhaust gas by-pass and variable solvent regeneration (VSR). It was found that for both coal- and gas-fired power plants, the VSR strategy is consistently the most profitable option. The performance of the exhaust by-pass scenario is a strong function of the carbon prices and is only selected at very low carbon prices. The viability of the solvent storage strategy was found to be a strong function of the capital cost associated with the solvent storage infrastructure. When the cost of the solvent tanks has been paid off, then the solvent storage scenario is 3.3% and 8% more profitable than the baseline for the pulverised coal and gas-fired power plants, respectively. Sensitivity analyses showed that, for all strategies, the flexibility benefit declined with reduced carbon and fuel prices, while a “peakier” electricity market, characteristic of one with significant quantities of intermittent renewables deployment, more significantly rewarded flexible operation.

  • JOURNAL ARTICLE
    Mellor A, Hylton NP, Maier SA, Ekins-Daukes Net al., 2017,

    Interstitial light-trapping design for multi-junction solar cells

    , SOLAR ENERGY MATERIALS AND SOLAR CELLS, Vol: 159, Pages: 212-218, ISSN: 0927-0248
  • JOURNAL ARTICLE
    Napp T, Bernie D, Thomas R, Lowe J, Hawkes A, Gambhir Aet al., 2017,

    Exploring the Feasibility of Low-Carbon Scenarios Using Historical Energy Transitions Analysis

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

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