UK Energy System Research Articles

Intermittency and periodicity in net-zero renewable energy systems with storage

The reducing cost of solar and wind energy together with the UK commitments to net-zero emissions will mean that UK energy systems for 2050 and similarly those in many other countries will be dominated by variable renewable supplies. Electricity systems are expected to be very reliable but renewable energy is inherently intermittent. We explore energy storage as a solution to this problem, considering the physics of the system to gain understanding of its needs, rather than using its economics, which may lead to less adequate designs.The scale and the periodic nature of the energy storage problem are crucial to system design. There are very different physical needs for storing energy for: days, weeks and years. Therefore a range of storage technologies with their differing characteristic will be required for these different periods.A UK energy system with three types of storage is modelled to both dimension and schedule these stores in light of the physical features and the cost parameters of potential storage technologies. The scale of the UK's energy storage need is large - more than a thousand times that of current storage systems - potentially increasing the energy costs of a 2050 energy system based largely on solar and wind, by a significant amount.Though the UK is considered as an example, the methods could be used for any country that is planning an energy system with a majority of variable renewables and a net-zero carbon target.

Mapping hydrogen storage capacities of UK offshore hydrocarbon fields and exploring potential synergies with offshore wind

Abstract Energy storage is an essential component of the transitioning UK energy system, a crucial mechanism for stabilizing intermittent renewable electricity supply and meeting seasonal variation in demand. Low-carbon hydrogen provides a balancing mechanism for variable renewable energy supply and demand, and a method for decarbonizing domestic heating, essential for meeting the UK's 2050 net-zero targets. Geological hydrogen storage in porous rocks offers large-scale energy storage over a variety of timescales and has promising prospects due to the widespread availability of UK offshore hydrocarbon fields, with established reservoirs and existing infrastructure. This contribution explores the potential for storage within fields in the UK Continental Shelf. Through comparison of available energy storage capacity and current domestic gas demands, we quantify the hydrogen required to decarbonize the UK gas network. We estimate a total hydrogen storage capacity of 3454 TWh, significantly exceeding the 120 TWh seasonal domestic demand. Multi-criteria decision analysis, in consultation with an expert focus group, identified optimal fields for coupling with offshore wind, which could facilitate large-scale renewable hydrogen production and storage. These results will be used as inputs for future energy system modelling, optimizing potential synergies between offshore oil and gas and renewables sectors, in the context of the energy transition.

The role of hydrogen and fuel cell technology in providing security for the UK energy system

It is not yet well understood how hydrogen and fuel cell technology could perform in the UK energy system (ES) and what influence it may have in contributing towards its security. This article aims to discuss the potential of a hydrogen economy examining its ability to reduce dependency on fossil fuels sourced both domestically and internationally. A snapshot of the hydrogen economy is presented introducing the latest development in hydrogen production technologies and distribution infrastructure. It has been postulated that with the introduction of a CO2 tax, integrating carbon capture and sequestration (CCS) systems with commercial hydrogen production technologies such as steam methane reforming (SMR), coal gasification (CG) and biomass gasification could significantly reduce the levelised cost of hydrogen (LCOH) production. The role of hydrogen and fuel cell technology in coupling the building, transport and industrial sectors has been demonstrated. Decarbonisation of heat in the UK is expected to incur a large cost for transitioning the incumbent network and it is expected that government assistance will be necessary to lessen the burden on consumers. Deployment of fuel cell combined heat and power (CHP) systems and integration into the UK ES could make great strides towards improving its security.

Values of latent heat and thermochemical energy storage technologies in low-carbon energy systems: Whole system approach

Thermal energy storage (TES) is widely expected to play an important role in facilitating the decarbonization of the future energy system. Although significant work has been done in assessing the values of traditional sensible TES, less is known about the role, impact and value of emerging advanced TES at the system level. This is particularly the case of latent heat thermal energy storage (LHTES) and thermochemical energy storage (TCS). In this context, this paper is dedicated to evaluating the techno-economic values for the whole UK energy system of LHTES and TCS technology using an integrated whole energy system model. First, the key concepts of the whole system modelling framework are introduced. Unique to this work is that the economic benefits delivered by LHTES and TCS to different levels of the UK energy system infrastructure and various energy sectors through the deployment of TES are explicitly analysed, which comprehensively demonstrates the values of selected TES technologies from the whole system perspective. A series of sensitivity studies are implemented to analyse the advantages and disadvantages of LHTES and TCS under different conditions. The simulation results indicate that TES can benefit different sectors of the whole energy system and drive significant cost savings, but the whole system values of TES is closely dependent on the decarbonization requirement. Although LHTES is characterized by relatively low capital costs, when TES penetration is limited and carbon target is tight, the advantage of TCS is outstanding due to its high energy density.

A Practice Evaluation and Discussion on the Application of the UK TIMES Model

UK TIMES is a model of the UK energy system developed by UCL and the UK Department of Business, Energy, and Industrial Strategy. The UK TIMES model depicts the UK’s energy system, from fuel extraction and trade to fuel processing and transport, power generation and all final energy demand. The model generates scenarios for the evolution of the energy system based on different assumptions around demand evolution, future technology costs, measured energy system costs, and all greenhouse gases related to the scenarios. In order to understand and analysis the current application status of this model in practical research, one journal paper about achieving net-zero emissions was selected as an example to be analysed. This paper will summarise the main features and key findings of the modelling exercise. At the same time, the paper will place this analysis in the broader research context by briefly drawing on other literature and describe how well the analysis follows best practice guidelines. Finally, this essay will provide three specific suggestions to the authors as to how they might improve their analysis. Clear justification for these recommendations will also be provided.

Which way to net zero? a comparative analysis of seven UK 2050 decarbonisation pathways

Since the UK’s Net Zero greenhouse gas emissions target was set in 2019, organisations across the energy systems community have released pathways on how we might get there – which end-use technologies are deployed across each sector of demand, how our fossil fuel-based energy supply would be transferred to low carbon vectors and to what extent society must change the way it demands energy services. This paper presents a comparative analysis between seven published Net Zero pathways for the UK energy system, collected from Energy Systems Catapult, National Grid ESO, Centre for Alternative Technology and the Climate Change Committee. The key findings reported are that (i) pathways that rely on less stringent behavioural changes require more ambitious technology development (and vice versa); (ii) electricity generation will increase by 51–160% to facilitate large-scale fuel-switching in heating and transport, the vast majority of which is likely to be generated from variable renewable sources; (iii) hydrogen is an important energy vector in meeting Net Zero for all pathways, providing 100–591 TWh annually by 2050, though the growth in demand is heavily dependent on the extent to which it is used in supplying heating and transport demand. This paper also presents a re-visited analysis of the potential renewable electricity generation resource in the UK. It was found that the resource for renewable electricity generation outstrips the UK’s projected 2050 electricity demand by a factor 12–20 depending on the pathway. As made clear in all seven pathways, large-scale deployment of flexibility and storage is required to match this abundant resource to our energy demand.

Flexible nuclear plants with thermal energy storage and secondary power cycles: Virtual power plant integration in a UK energy system case study

Electricity markets are fast changing because of the increasing penetration of intermittent renewable generation, leading to a growing need for the flexible operation of power plants to provide regulation services to the grid. Previous studies have suggested that conventional power plants (e.g., nuclear) may benefit from the integration of thermal energy storage (TES), as this enables greater flexibility. In conventional Rankine-cycle power plants, steam can be extracted during off-peak periods to charge TES tanks filled with phase-change materials (PCMs); at a later time, when this is required and/or economically favourable, these tanks can feed secondary thermal power plants to generate power, for example, by acting as evaporators of organic Rankine cycle (ORC) plants. This solution offers greater flexibility than TES-only solutions that store thermal energy and then release this back to the base power plant, as it allows both derating and over-generation. The solution is applied here to a specific case study of a 670 MWel nuclear power plant in the UK, which is a typical baseload power plant not intended for flexible operation. It is found a maximum combined power of 822 MWel can be delivered during peak demand, which is 23% higher than the base plant's (nominal) rated power, and a maximum derating of 40%, i.e., down to 406 MWel during off-peak demand. An operational energy management strategy (EMS) is then proposed for optimising the charging of the TES tanks during off-peak demand periods and for controlling the discharging of the tanks for electricity generation during peak-demand periods. An economic analysis is performed to evaluate the potential benefits of this EMS. Profitability in the case study considered here can result when the average peak and off-peak electricity price variations are at least double those that occurred in the UK market in 2019 (with recent data now close to this), and when TES charge/discharge cycles are performed more than once per day with a discharge duration to the ORC plants longer than 2 h. When considering the most recent UK electricity prices in 2021 (to-date), the EMS investment cost for one 1-h charge and 1-h discharge cycle per day is 199 m£ with a total generation of 50 GWh per year and a levelised cost of electricity (LCOE) of 463 £/MWh. The investment cost drops significantly to 48 m£ when discharging for a longer duration of 8 h as the size of the ORC plants decrease. The projected LCOE also decreases to 159 £/MWh when doubling the total generated electricity (100 GWh/year) by employing two 8-h TES charge/discharge cycles per day. Importantly, it is found that the economics of the EMS are determined by a trade-off between longer discharge durations to the ORC plants that minimises their size and cost, and shorter charge/discharge durations that yield the highest spread between off-peak and peak electricity prices.

The causes of risk in fuel supply chains and their role in energy security

Managing risk is of central importance in achieving energy security, yet a methodology for identifying and assessing all relevant risks has previously been lacking. From an extensive review of risk and the operation of fuel supply chains, 34 distinct generic causes of risk have been recognised. These risks were analysed for the UK's energy system, considered as 19 fuel supply chains (each with six stages), and scored by likelihood and impact on the supply chain (accounting for resilience). A risk matrix was constructed recording the risks encountered at each stage for each fuel. For the UK, the three causes with the greatest total score were ‘lack of access to capital’, ‘changing policy or regulatory framework’ and ‘significant public concern’, all of which were amongst the eight causes of risk noted as most significant at an expert verification workshop. This methodology yields a credible and direct quantification of risk for a national energy system – an indicator of energy security. It does not require the assignment of weighting factors to various contributory characteristics, often arbitrarily chosen in other approaches. It is suggested that the seven most prevalent causes of risk, that occur for nearly all fuels and all stages, may be systemic in nature. The method offers sufficient flexibility to make it readily applicable to other nations, regions, or sites, and other types of supply chain.

Environmental life cycle assessment of heating systems in the UK: Comparative assessment of hybrid heat pumps vs. condensing gas boilers

Residential space heating is one of the major contributors to greenhouse gas (GHG) emissions and hence a priority sector to decarbonise in the transition to Net Zero target by 2050 in the UK. To assess environmental impacts of a current heating system and potential alternatives in the UK, this study conducted a comparative LCA of a condensing gas boiler and a hybrid heating pump for a common type of UK’s existing houses (a semi-detached house). The functional unit of this study is defined as delivering space heating for the whole lifetime (20 years) of heating system. The results suggest that the hybrid heat pump potentially saves 30% of GHG emissions as compared to the condensing gas boiler in the core scenarios (4.5E + 04 kg CO2-eq/FU vs 6.4 E + 04 kg CO2-eq/FU respectively). The hybrid heat pump also shows 13% to 48% emission reduction as compared to the condensing gas boiler in terrestrial acidification, photochemical oxidant formation, particulate matter formation and fossil depletion. However, the hybrid heat pump emits 3 to 6 times more emissions in terms of human toxicity, water depletion and metal depletion than the condensing gas boiler. The production phase contributes around 50% of the impact for metal depletion and human toxicity in both core scenarios, while the use phase dominates in other selected impact categories. The combustion of natural gas and the electricity production are the major causes for the dominance of the use phase for all selected impact categories excepting metal depletion and human toxicity. The sensitivity scenarios support the robustness of the results. Further work is needed to understand the role hybrid heat pumps can play in the residential sector decarbonisation under different scenarios of residential uptake, household behaviour and wider UK energy system decarbonisation.

Tools and options for hydrogen and CCS cluster development and acceleration – UK case study, ELEGANCY project

Development of hydrogen and Carbon Capture and Storage (CCS) in the United Kingdom is investigated for the UK by research in the ELEGANCY Project to accelerate carbon dioxide (CO2) emissions reduction. Industry plans and concepts including large-scale production of hydrogen with CCS (H2-CCS) are used to estimate the potential magnitude and rate of CO2 supply for the Grangemouth and Teesside industrial sites. Annual emissions reductions from these two sites by CCS operations could exceed 30 million tonnes (Mt) by 2035 and 50 Mt by 2045. Implementation of carbon-negative technologies would increase these estimated reductions. The application of the H2-CCS chain tool to Great Britain has identified the resource and technology needs for scaling up the H2 economy. It has also highlighted challenges to overcome such as the increased costs, magnitude of H2 and CO2 storage requirements, reduction in upstream emissions, etc. Importantly, there is an urgent need for policy makers, regulators, suppliers, and consumers to coordinate their efforts to achieve timely progress towards net-zero in a socially responsible manner. An application of the business model and business case assessment methodology and tools to the delivery of large-scale H2-CCS infrastructure for decarbonising residential heating in the north of England is presented. A resulting high-level system business model which allows the removal of the investment barriers and addresses major business risks to investment is defined through realistic risk allocation and collaboration between the public and private sectors. A conceptual business case is articulated with a strategic rationale consistent with support for UK energy system decarbonisation and the UK government’s legal 2050 net-zero emissions target. Recommendations for achieving the first phase of infrastructure development ensuring low regrets outcomes and flexible real options are described.

Transitions, disruptions and revolutions: Expert views on prospects for a smart and local energy revolution in the UK

Alongside ambitious targets for economy-wide decarbonisation, a ‘smart and local energy revolution’ narrative has recently emerged in energy policy and research. To consider the energy revolution proposition, this paper presents findings from a Policy Delphi survey of interdisciplinary energy researchers and stakeholders (n = 113) on alternative transition paths (disruptive or continuity-led) for the UK energy system. The paper includes quantitative and qualitative survey findings on a number of social and technical aspects of the energy revolution proposition: system governance, security and flexibility arrangements, power sector decarbonisation, the future of large supply firms and energy policy priorities. The results suggest that rather than a wholesale revolution the UK's energy transition over the next two decades will involve a mix of disruptive and continuity-led elements. Experts differ on a number of issues associated with the energy revolution proposition, including the impact of demand side response on whole system flexibility and whether energy systems are best governed at a local or national scale. However, rather than having fixed orientations to either disruption or continuity-led change, most experts respond on an issue-by-issue basis. The energy revolution proposition is socially constructed and contestable, and whole energy systems policy and research should go beyond uniform transition narratives.

Governance institutions and prospects for local energy innovation: laggards and leaders among UK local authorities

UK Local Authorities are increasingly declaring ‘climate emergencies’ and pledging 100% clean energy and carbon neutrality ambitions for their locality, despite lack of powers over energy systems. Our research investigates current Local Authority engagement in clean energy, and considers prospects for meso-scale innovation. The analysis allocates Local Authorities to one of four categories of engagement, from energy ‘laggards’ through to ‘leaders’, based on their energy plans and investments. Findings reveal that, despite lack of direct powers, a high proportion of Local Authorities have developed sustainable energy plans and projects, but only a minority manage to combine these into a more strategic local programme. There was proportionately greater activity in Scotland and considerable variation was found across English regions. We conclude that variation in levels of engagement relates to authority size and divisions of responsibilities between different levels of government. The capacity for Local Authority-mediated social innovation to support development of a clean UK energy system is discussed. Implications for policy include the need for a statutory power, and commensurate resources, for Local Authorities, to ensure a more comprehensive and systematic contribution to clean energy innovation.

Mapping participation: A systematic analysis of diverse public participation in the UK energy system

This paper develops a novel approach to mapping diverse forms of participation and public engagement, using the example of the UK energy system. It builds on emerging systemic accounts of participation, which go beyond a focus on individual instances of participation, to gain an understanding of broader patterns and connections. Our approach, which forms part of an emerging family of methods that seek to map across multiple forms of public involvement in issues and systems, draws on systematic review methodology and a relational co-productionist conception of participation. The findings of a systematic mapping of public participation related to the UK energy system 2010–2015 are presented, comprising 258 cases in total. The mapping analysis reveals patterns as to the what (energy objects and issues), how (procedural formats) and who (publics) of energy participation in the UK, which go far beyond the conventionally assumed forms and sites of public participation around energy. Implications for how the dynamics of ‘whole system’ energy participation are represented and the role of approaches to mapping participation in governing energy transitions are considered.

Exploring the Role and Value of Negative Emissions Technologies to the UK Energy System

Exploring the Role and Value of Negative Emissions Technologies to the UK Energy System

The impact of policy changes: The opportunities of Community Renewable Energy projects in the UK and the barriers they face

The UK's energy system is predominantly centralised with a major reliance on fossil fuels. The trilemma of successfully delivering energy security, equity, and environmental sustainability, whilst dealing with an ageing energy infrastructure, demands change within the entire energy system. In recent years, Community Renewable Energy (CRE) projects have played a significant role in the transition of the UK's energy system, but since 2016 government support for them has been less robust. This paper reports a web-based survey and semi-structured interviews of the UK's community energy groups undertaken between August 2016 and March 2017. The results indicate that huge problems have arisen due to the changes in government policy, particularly for solar photovoltaic schemes. The majority of CRE organisations have chosen to focus on managing their existing assets rather than plan further growth. Additionally, this paper highlights the key challenges facing CRE projects that wish to develop innovative business models under the new policy conditions.

The role and value of negative emissions technologies in decarbonising the UK energy system

The UK is committed to the Paris Agreement and has a legally-binding target to reduce economy-wide greenhouse gas emissions by 80% relative to 1990 levels by 2050. Meeting these targets would require deep decarbonisation, including the deployment of negative emissions technologies. This study, via a power supply capacity expansion model, investigates the potential role of bio-energy with carbon capture and storage (BECCS) and direct air capture and storage (DACS) in meeting the UK's emissions reduction targets. We show that to achieve power sector decarbonisation, a system dominated by firm and dispatchable low-carbon generators with BECCS or DACS to compensate for their associated emissions is significantly cheaper than a system dominated by intermittent renewables and energy storage. By offsetting CO2 emissions from cheaper thermal plants, thereby allowing for their continued utilisation in a carbon-constrained electricity system, BECCS and DACS can reduce the cost of decarbonisation by 37–48%. Allowing some this value transferred to accrue to NETs offers a potential route for their commercial deployment.

Dynamics of technological change: nuclear energy and electric vehicles in France

Technological change is shaped by a confluence of processes that are governed by socio-political, economic, and regulatory factors within a region. In this paper, the authors present a theoretical framework to describe the dynamics of technology change. Based on a qualitative modelling approach, the authors employ concepts from literature on innovation, technology adoption, and technological change, and map reinforcing and retarding cycles of processes of innovation. The way these processes (or functions) are interconnected and combined hinders or enables the overall success of technology diffusion and shapes the long-term outcome for the new technology. The authors develop the framework with examples of energy systems in UK and UAE, and apply the model to examine two cases of nuclear power and electric vehicles in France. They highlight the role as well as limits of policy in initiating and sustaining reinforcing cycles for new technology diffusion and can provide a basis for forming expectations about emerging technologies.

Energy Supply and Decarbonisation Beyond Brexit: Politics and Policy

Energy Supply and Decarbonisation Beyond Brexit: Politics and Policy

Comparative assessment of innovative and conventional food preservation technologies: Process energy performance and greenhouse gas emissions

Abstract This study aims to establish whether innovative food preservation technologies can offer significant reductions in energy consumption and corresponding greenhouse gas (GHG) emissions while delivering equivalent microbiological lethality, nutritional and organoleptic quality to conventional processes. The energy demand of high pressure processing, microwave, ohmic and conventional heating technologies, for achieving the same pasteurising effect in orange juice under commercially-representative processing conditions are measured and compared. The corresponding GHG emissions are evaluated using UK energy system emissions data, while the effect of equipment scale is explored empirically. The results show that for the same product quality, the innovative technologies are more energy- and non-renewable primary resource-efficient, with ohmic heating performing best, followed by high pressure processing at high fill-ratios. More significant improvements are expected in future, provided electricity grid decarbonisation is sustained. Energy performance improves with equipment scale for the microwave and high-pressure systems, but remains essentially constant for ohmic heating. Industrial relevance Using orange juice pasteurisation as case study, this work shows that for similar product quality, electrically-driven innovative food pasteurisation technologies like high pressure processing, ohmic and microwave heating are more beneficial than conventional techniques energy- and emission-wise, if a sufficient portion of the electricity is renewable. This is the case given the current decarbonisation level of the UK electricity grid and is expected to be more significant as more electricity is sourced renewably in the future as currently projected. The result should aid future industrial investment decisions.

Ecologies of participation in socio-technical change: The case of energy system transitions

Studies of societal engagement with socio-technical change are undergoing a systemic turn. Rather than simply viewing public engagement in science, policy and behavioural change in terms of discrete cases, key social theories in deliberative democracy, practice theory, socio-technical transitions and co-productionist scholarship in science and technology studies (STS) are moving to consider how diverse forms of participation interrelate in wider systems. In this paper we take stock of these advances to develop a conceptual framework for understanding ecologies of participation in socio-technical and democratic systems, grounded in relational co-productionist theory in STS. The framework is illustrated through empirical analysis of a systematic mapping of participation in UK energy system transitions between 2010 and 2015. This provides the first insights into system-wide patternings, diversities and inequalities of energy participation, the significant types of interrelation between practices of public engagement within wider ecologies of participation, and their mutual construction with political cultures and constitutions. The value and implications of adopting an ecologies of participation approach are considered with respect to the theoretical, empirical and practical challenges of understanding and building more inclusive, responsible and just socio-technical (energy) transitions.