Generation Integrated Energy Storage - A Paradigm Shift

Lead Research Organisation: University of Nottingham
Department Name: Faculty of Engineering

Abstract

This project will assess a class of systems that blend electricity generation and storage, to understand the role that they could play in future energy systems. Their ability to deliver low-carbon energy on demand, at low system cost, will be investigated from technical, economic, and policy standpoints.

With a growing fraction of electricity consumption being supplied by variable renewable energy sources, the ability to match energy generation and energy consumption is rapidly taking centre stage. Flexible ('dispatchable') coal and gas plants are being displaced to lower carbon emissions. At present, both nuclear and renewable energy technologies are generally configured to generate as much electricity as possible, regardless of the electricity demand at the time. Standalone energy storage, in which surplus electricity is converted to an intermediate energy form and then back again, is emerging as a vital partner to these generation technologies but it is prohibitively expensive for the duties that will be required in the near future. Active management of electricity demand (by shutting down or deferring loads) and electrical interconnections with neighbouring countries will also play important roles but these also have costs and they will not obviate the need for storage.

This project will build a deep understanding of a class of system which takes a different and potentially much lower cost approach. These Generation Integrated Energy Storage (GIES) systems, store energy in a convenient form before converting it to electricity on demand. The hypothesis is that the lowest cost and highest performance storage can be achieved by integrating generation and storage within one system. This avoids the expense and inefficiency of transforming primary energy (e.g. wind, solar, nuclear) into electricity, then into an intermediate form, and later back to electricity. For example, the heat produced by a concentrating solar power plant can be stored at far lower cost and with lower losses than producing electricity directly and operating a standalone electricity store.

A broad range of opportunities exist for low-carbon GIES systems, in both renewable and nuclear applications. The research team's expertise in wind, nuclear, and liquefied air storage will be applied directly to GIES systems in all three. The project will also establish a framework for the wider significance of GIES to energy systems. Technical and thermodynamic metrics that characterise high performing GIES systems will be developed, and used to compare with standalone generation and storage equivalents. The theoretical groundwork laid by this research will have applications far beyond the current project. Opportunities for current and future technologies will be mapped out and publicised, supporting and accelerating further work in the field. The deployment and operation of such technologies will be modelled by means of a pragmatic real options economic analysis. The unique policy and economic considerations of fusing generation and storage will be reviewed in detail, considering challenges and proposing solutions to regulatory and financial hurdles. Taken in concert, these will determine the value and scope for substantial deployment of GIES systems.

In bringing to light the potential of the class of GIES systems, the research team will rectify a gap in energy systems thinking, in time to inform what will be a multi-billion pound expenditure in the coming decade. By providing the tools to analyse and deploy these systems, the research will open up a new avenue for cost-effective flexibility across the energy infrastructure of the UK and other regions worldwide.

Planned Impact

Our research and analysis will show how Generation-Integrated Energy Storage (GIES) systems can make an invaluable contribution to the continued deployment of low carbon generation up to high penetration levels. Integrating a small fraction of inflexible low carbon generation into our energy system has been comparatively easy because the remaining fossil-fuelled generation could be flexed to balance supply with demand. Each additional 10% becomes more difficult and even the commitment to draw 30% of electricity from renewables by 2020 will bring major balancing challenges.

The 2016 report by the Carbon Trust and Imperial College suggests that savings associated with introducing energy storage into the UK system could be between £2.4bn and £7bn per year by 2030. These estimates were based on received values for the costs and performance of energy storage in standalone systems like pumped-hydro and simple compressed air plant, flywheels, batteries and isolated liquid air systems. We expect to show that very substantial quantities of storage can be implemented in "GIES mode" with high performance and exceptionally keen cost. We expect, as a result, to show that the system savings can be significantly higher and to play some small part in seeing these benefits realised. A natural consequence will likely be that higher penetrations of low carbon generation will be adopted than would otherwise be the case.

Specific stakeholders in the public and private sectors will benefit from the project:

- In the private sector we will make the case for technology development in a relatively new application area, where energy storage is integrated with power generation. Most emphasis thus far has been on energy storage which stands apart from generation. Whilst recognising that this (standalone storage) is an extremely important area that will inevitably see enormous future growth, there is the potential that GIES systems will have a similar destiny starting from almost-zero at present. The project will bring a completely new set of players into the energy storage market - parties presently focused on low-carbon generation of various sorts.

- For the public sector, our analysis of the value of GIES will inform the development of future energy system pathways, assessing how this new class of technologies can increase the efficiency of the energy system in the transition to low carbon. We will also describe the barriers to its deployment, providing recommendations for policy-makers that will help ensure its potential is reached.

We will achieve this impact from a combination of approaches:

- Engagement with a panel of industrial participants committed to supporting the project and with a network of prestigious international universities who recognise the potential that GIES approaches can be transformative.

- Wide stakeholder workshops over the course of the project to draw in the expertise of the energy sector from across policy, industry and academia.

- Direct interaction with the energy community through formal interviews, participation in external workshops/conferences/meetings, and through links with networks such as the Energy Storage Supergen Hub.

- Dissemination of emerging and final results through peer-reviewed academic papers, more accessible reports and policy briefings, and presentations at relevant events.

Publications

10 25 50
publication icon
Cárdenas B (2019) A load-based approach for optimizing a packed-bed thermal store in Journal of Energy Storage

publication icon
Cárdenas B (2018) A sign-preserving filter for signal decomposition in Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering

publication icon
Cárdenas B (2019) Wire-wound pressure vessels for small scale CAES in Journal of Energy Storage

publication icon
Davenne T (2017) The cold store for a pumped thermal energy storage system in Journal of Energy Storage

 
Description The context of energy has changed profoundly since the start of this work. This was anticipated by the project proposal but not caused directly by the project work. Two main things happened: (a) renewable energy generation became very much lower in LCoE and (b) the targets for CO2 reduction changed from 90% reduction relative to a 1990 base to "Net Zero". These factors now mean that medium-duration energy storage has leapt up the agenda.
Exploitation Route A meeting is being arranged for March 23, 2020 at which "Medium-Duration Energy Storage" will be discussed extensively by experts in front of important policy-makers. This meeting will almost-certainly be pivotal in making space in the policy landscape for an important class of energy storage that has been sorely neglected thus far.
Sectors Energy

 
Description Generation Integrated Energy Storage has the potential to make savings of ~13% in net-zero UK relative to the least expensive solution not including that integrated storage - if the engineering associated with integrating this storage is as feasible as the work from this grant has suggested. This was found from a study done jointly with BEIS and using one of BEIS' own scenarios for a Net Zero 2050. BEIS agreed that an independent professional review should be carried out to explore this important point. The latter study has stalled at this present point (March 2022) but it is expected that when this study resumes, it will stimulate a new manufacturing industry.
First Year Of Impact 2021
Sector Energy
Impact Types Economic

 
Description Disruptive Innovations in Energy
Geographic Reach National 
Policy Influence Type Participation in a advisory committee
 
Description GasNetNew - The role of the gas network in a future decarbonised UK
Amount £1,287,080 (GBP)
Funding ID EP/W008726/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 01/2022 
End 06/2025
 
Description Sustainable, Affordable and Viable Compressed Air Energy Storage (SAVE-CAES)
Amount £1,095,204 (GBP)
Funding ID EP/W027569/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 06/2022 
End 06/2025
 
Company Name CHEESECAKE ENERGY LIMITED 
Description Cheesecake Energy Ltd. (CEL) is developing and selling a medium-scale (150kW), medium-duration (5hrs - 12hrs of discharge time) energy storage system. The system stores energy in the combined forms of pressurised air (34%) and heat (66%). The system uses modified ex-service truck engines to become compressor/expander machines and uses its own unique valve-actuation system to enable the same machine to serve as compressor (for charging) and as expander (for discharging). The system includes significant amounts of natural inertia but also has the capability to include more based on the findings from the SHyKESS research programme. 
Year Established 2016 
Impact Impacts are only just beginning but CEL has secured a contract with Colchester Amphora to support a business part and it will account for several millions of pounds of cost saving on this site alone. It is being explored seriously for supporting EV charging stations.
 
Company Name CHEESECAKE ENERGY LIMITED 
Description Cheesecake Energy Ltd. (CEL) is developing and selling a medium-scale (150kW), medium-duration (5hrs - 12hrs of discharge time) energy storage system. The system stores energy in the combined forms of pressurised air (34%) and heat (66%). The system uses modified ex-service truck engines to become compressor/expander machines and uses its own unique valve-actuation system to enable the same machine to serve as compressor (for charging) and as expander (for discharging). The system includes significant amounts of natural inertia but also has the capability to include more based on the findings from the SHyKESS research programme. 
Year Established 2016 
Impact Impacts are only just beginning but CEL has secured a contract with Colchester Amphora to support a business part and it will account for several millions of pounds of cost saving on this site alone. It is being explored seriously for supporting EV charging stations.
 
Description One-day workshop:: Medium-Duration-Energy-Storage-2022 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Held at the IMechE Headquarters in Westminster, London, on March 16, 2022, this event aimed at consolidating the importance of medium-duration-energy-storage. There were speakers representing five different technologies as well as a certification agency, a government agency (BEIS), a trade association (the Renewable Energy Association) and the transmission system operator (National Grid).
Year(s) Of Engagement Activity 2022
URL http://www.era.ac.uk/Medium-Duration-Energy-Storage-2022
 
Description One-day workshop on MEDIUM-DURATION-ENERGY-STORAGE 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact A one-day event was held on "Medium-Duration Energy Storage". Full details are available at www.era.ac.uk/Medium-Duration-Energy-Storage . This event sought to enlighten policy-makers in particular about the huge importance of energy storage with discharge durations between 4 and 200 hours. 70 people attended on the day and many more have accessed the files subsequently.
Year(s) Of Engagement Activity 2020
URL http://www.era.ac.uk/Medium-Duration-Energy-Storage
 
Description One-day workshop:: Grid Inertia 2020: Current perceptions and future directions. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Grid inertia is the first line of defence in helping the electricity grid to balance supply and demand. Neither wind turbines nor photo-voltaic panels endow the grid naturally with inertia and as the penetration of renewables increases dramatically (as it will continue to do), we are approaching a crisis of grid non-robustness. The major blackout of August 8, 2019 might have been averted if there had been more grid inertia on the system.

This event brought together specialists in the area to discuss the present state of technology, policy and markets. The event was thoroughly appreciated by all attendees - to the extent that there is an obvious need for this event to become annual. The 2021 event is now organised for May 11, 2021.
Year(s) Of Engagement Activity 2020
URL http://www.era.ac.uk/Grid-Inertia
 
Description One-day workshop:: Grid Inertia 2021 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Grid inertia is a major issue for a decarbonising grid. National Grid, EDF, ESB (the main Irish utility) and EPRI were main contributors to the organisation of this event but there were contributions also from the grids in Finland and Australia. This event provided a highly-useful forum for the assembly and sharing of knowledge about the requirements for grid inertia, the means by which it can be achieved and how it can be measured. There were afternoon breakout sessions on 5 separate topics including a tutorial on what synchronous machines actually do for the grid (not just inertia) and on how inertia is present in most of the "thermo-mechanical energy storage" technologies. Building on the event run in 2020, there is now strong impetus for an annual event.
Year(s) Of Engagement Activity 2021
URL http://www.epri.com/events/844574B6-537B-47F5-9634-7EB7646DC9CF
 
Description One-day workshop:: Hydrogen Storage in Caverns 2021 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Hydrogen Storage in Caverns 2021 was established in order to clarify the broad point that there are really four important time ranges of energy storage. Energy storage with the longest discharge durations is dominated by fuels - and probably by hydrogen in particular. The key criterion for this storage is cost per unit of energy output. The cost per unit power is much less important. This event is the only one of its kind and was extremely well received. It led subsequently to the running of "Hydrogen Storage in Caverns 2022" and it is clear from that there must be an annual event on this topic.
Year(s) Of Engagement Activity 2021
URL http://www.era.ac.uk/Hydrogen-Storage-in-Caverns-2021
 
Description One-day workshop:: Hydrogen Storage in Caverns 2022 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Hydrogen Storage in Caverns 2022 was a natural follow-on from the event run in 2021. As noted in connection with the 2021 event, the main purpose was to clarify that a Net-Zero energy system will require very large quantities of "long-duration energy storage" (storage with discharge durations lasting 200 hrs or more). Quantities in the order of 100TWh are now being discussed and these are achievable - but they are affordable only through the use of fuels. It is essential that there is some policy movement towards starting to build-out the required storage. That storage is very likely to be realised using hydrogen in caverns. The event involved policy-makers, private entrepreneurs, geologists, certification agencies and academics studying the broad future requirements of the energy system.
Year(s) Of Engagement Activity 2022
URL http://www.era.ac.uk/Hydrogen-Storage-in-Caverns-2022
 
Description Policy Briefing on the need to change the CfDs system 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact The system of CfDs for offshore wind prejudices irrationally against the possibility that storage could be integrated with offshore wind turbines. A virtual briefing event was held on May 15th of 2020 for which 14 politicians signed-up. Subsequently, the PDF (at the URL below) was created.
Year(s) Of Engagement Activity 2020
URL http://www.nottingham.ac.uk/Policy-and-Engagement/Documents/Wind-power/Renewable-Energy-Change-CfDs-...