Characterisation of the Field
Energy storage can be divided into several broad categories, electrical, thermal and fuel. Electrical energy and thermal energy are usually generated from energy fuel on demand by scheduling generators, however energy storage may be used to increase efficiency. The increasing use of renewable energy sources, where availability may not coincide with demand, increases the need for electrical and thermal storage.
The scope ofthis Landscape is the storage of electricity, where the storage input and output are electrical power. This Landscape does not include the storage of thermal energy for end use; the storage of fossil fuels including gas, coal and oil; or the storage of other commodities used in electrical power generation such as uranium. Carbon Capture and Storage (CCS) is covered in the UKERC CO2 Capture and Storage Landscape. Hydrogen storage is included where this is part of an electrical energystorage and regeneration system such as Power-to-Gas, while hydrogen storage generally is described in the UKERC Hydrogen Landscape.
Technologies used in electrical energy storage are covered, within the broad categories of chemical, mechanical, electrical and thermal technologies.
Electrical energy storage is an enabling technology at various scales, with application to a) the management of intermittency and efficiency in large scale power generation; b) transportation using low-emission electric vehicles (EVs); and c) portable electronics.
Interest is increasing generally in grid-scale electrical energy storage technology and applications. Investigations and reports have been completed in the UK and Europe, for example:
The UK Government’s Clean Growth Strategy (updated April 2018) plans to cut greenhouse gas emissions by upgrading our energy system, and announced an investment of £265m in smart systems to reduce the cost of electricity storage. In response, Ofgem produced a plan to upgrade our energy system and enable the transition to low carbon. Storage is seen to be an important part of a flexible energy system, and the plan includes discussion of actions to remove barriers to implementing effective storage and smart systems8.
The Industrial Strategy Challenge Fund (ISCF), announced in the 2018 Budget, is part of the UK Government’s Industrial Strategy, a long-term
plan to raise productivity and earning power in the UK. The fund is a core pillar in the Government’s commitment to increase funding in research and development by £4.7 billion over 4 years to strengthen UK science and business, and will invest in the world-leading research base and highly-innovative businesses to address the biggest industrial and societal challenges today. The ISCF Faraday Battery Challenge is one of the 15 Challenges funded, and will invest up to £246m to develop batteries that are cost-effective, high-quality, durable, safe, low-weight and recyclable, with a focus on the next generation of batteries for electrical vehicles and other applications. The ISCF and the Faraday Battery Challenge include funding for basic research, applied research, and demonstration activity, and are described where appropriate in Section 3, Section 4, and Section 5.
The All Party Parliamentary Group (APPG) on Energy Storage, considered the opportunity for battery storage in the UK, not only to provide energy security, but also to provide export potential9.
The Engineering and Physical Sciences Research Council (EPSRC) has identified storage as a priority area, in order to maintain and further develop energy storage research in the UK. Funding in the UK for basic and applied research and development of storage systems has increased dramatically in recent years.
In January 2009 EPRSC’s energy storage grant portfolio in the Energy Programme included 15 grants with total value £8m; while in 2013 EPSRC support for the energy storage topic included 23 grants, with total grant value £37m. In 2019 the EPSRC Energy Storage Research Area has 65 relevant grants with proportional value £106m, equivalent to 2.22 of the total EPSRC portfolio.
A particular uncertainty and area for research and development is the cost and lifetime of candidate storage technologies when applied to real duty cycles within electricity networks.
The UK is well established as a centre for battery development, with the main focus on lithium batteries, an important technology for mobile and stationary applications alike. Cryogenic (liquid-air) energy storage is also a UK strength.
The main research and development challenges are to reduce cost, and improve storage performance particularly in terms ofenergy density and round-trip efficiency, and lifetime during charge and discharge cycling. Research needs for storage technologies have been comprehensively described in research reports4,6, and generally include research into new materials and manufacturing methods.
1 Energy Research Partnership: The Future Role of Energy Storage in the UK, June 2011
2 Report for the Carbon Trust: Strategic Assessment of the Role and Value of Energy Storage Systems in the UK Low Carbon Energy Future, Imperial College, June 2012
3 Low Carbon Innovation Co-ordination Group: Electricity Networks and Storage Technology Innovation Needs Assessment, August 2012
4 European Commission DG for Energy: The future role and challenges of Energy Storage, January 2013
5 European Commission DG for Energy: Study on energy storage – Contribution to the security of the electricity supply in Europe, March 2020
6 Brandon et al., UK Research Needs in Grid Scale Energy Storage Technologies, April 2016
7 Renewable Energy Association (REA): Energy Storage in the UK, An Overview, 2nd Edition Autumn 2016
8 Ofgem, Upgrading our Energy System, July 2017
9 All Party Parliamentary Group (APPG) on Energy Storage, and Renewable Energy Association (REA): Batteries, Exports, and Energy Security, December 2017
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Table 2.1: UK Capabilities
Research and development of energy storage technologies has a long history in the UK.
UK Universities have particular strengths in materials for clean energy applications and in catalysis. Many Universities are active in battery research and development, as described in Section 3. There is also significant commercial R&D activity and expertise in all storage technologies and particularly in materials for electrochemical batteries. Some of the emerging capabilities in the UKare described in this section.
Battery storage systems in the electricity distribution network are already at the commercial deployment stage in the UK. There are numerous start-up companies, for example, Zenobe Energy deployed over 70MW at nine sites as of 2019. Moixa is a leading smart battery company, deploying residential batteries and solar systems since 2010, and offers integrated hardware and software for renewable energy management. RNA Energy has already over 200MW of operating renewable energy assets in the UK and in 2019 formed a joint venture with Nippon to construct two 50MW behind-the-meter storage projects in the UK. Pivot Power is developing the world s largest transmission-connected battery storage and electric vehicle charging network, and is the lead participant in the Energy Superhub Oxford project.
Statistics on energy storage projects published by RenewableUK in December 2019 shows that energy storage power capability is increasing rapidly in the UK, with 0.742GW of operational battery storage capacity and over 10GW of planning applications. Pumped storage is also increasing from2.833GW operational, and 1.796GW planned. While lithium batteries make up the majority of planned projects, the next phase of growth will include a range of new technologies. Companies ranging from Siemens to Highview Power are developing hydrogen, ammonia, and compressed air and liquid air storage technologies, with 0.600GW in development.
Meanwhile research continues in many storage technologies.
Significant advances inlithium-ion (Li-ion) battery technology have been historically made in the UK. AEA Harwell, working with Dowty Battery Co. in the 1990’s, developed solid-state lithium batteries with polymer electrolyte and composite cathode. There are established academic centres, and technology development and commercial exploitation continues with several companies in the field.
Johnson Matthey Battery Systems (formerly Axeon UK) is one of Europe’s largest lithium-ion battery systems suppliers, processing over 70 million cells a year, and supplying volume production of batteries for global markets. In Poland, Johnson Matthey designs and manufactures high performance battery packs for the professional cordless power tools and electric bike markets. The UK-based automotive battery systems business was acquired by Cummins in January 2018.
Nexeon (Abingdon) is a world leader in engineered silicon materials for battery applications. Nexeon’s technology uses silicon in several forms to enhance or replace the traditional graphite anode in a lithium ion battery. The technology has the potential to improve cycle life and significantly increase the capacity of Li-ion batteries used in electric vehicles and a wide range of consumer electronics.
OXIS Energy (Abingdon) has been at the forefront of building next generation batteries since 2004. The company has developed its unique Lithium-sulphur (Li-S) technology around a sulphur based cathode, Lithium metal anode, and a safe and highly stable electrolyte.
There are two main classes of flow batteries – the redox (reduction-oxidation) flow battery, and the hybrid flow battery where the electrodes are part of the chemical reaction (as in a battery).
The UK has been active in flow battery development. In the 1990’s Regenesys (UK) developed polysulphide bromide technology to an advanced stage, and two demonstration plants of 15MW and 120MWh capacity were constructed but not commissioned. The technology rights were acquired by VRB Power Systems (Vancouver) in 2004 to complement its own technologies (vanadium), providing products for very large utility-scale applications from 10–100MW, with eight to ten hours’ storage time. VRB ceased trading in 2008 and after several changes of ownership the technology is now marketed by VRB Energy.
redT Energy PLC (Renewable Energy Dynamics Technology) developed three generations of vanadium redox battery in the UK since 2016. In 2019, redT flow batteries achieved pre-qualification status from National Grid to provide Dynamic Firm Frequency Response (dFFR) services to the UK electricity transmission grid. The company is supplying a 2.5 MW / 5 MWh vanadium redox flow cell as part of a 60MW flow/hybrid energy storage system to the Energy SuperHub Oxford project. In 2020 redT Energy and Avalon Battery merged to form Invinity Energy Systems, now a worldwide leader in vanadium flow batteries and a competitor to lithium-ion technology.
Research on zinc-cerium flow batteries continues at the Universities of Strathclyde and Southampton. The University of Southamptonis also researching the soluble lead redox flow battery (SLFB).
Urenco Power Technologies (UPT) developed a 2kWh capacity flywheel with a high speed composite rotor, using expertise in high speed centrifuges developed at Capenhurst. Although the flywheel was successfully used in field trials in the traction application, and was used to demonstrate smoothing wind power fluctuations from a wind turbine in Japan, UPT ceased production in 2003
Williams Hybrid Power developed flywheel technology for use in Formula 1 racing, and sold the technology to GKN where it is included in technologies for development of next-generation vehicles at the GKN UK Innovation Centre in Abingdon.
Innovate UK has funded several projects for development of flywheel application to vehicles. Developments for hybrid automotive drivetrain applications could have power grid applications that require high power, low energy storage.
More than a decade of research at Cambridge University has resulted in development of superconducting magnetic bearings for flywheels, suitable for application to the power grid and industrial uninterruptible power supplies (UPS).
OXTO Energy has developed a flywheel with a steel rotor to work alongside intermittent renewable generation.
Cryogenic energy storage
Highview Power Storage is a developer of utility-scale energy storage and power systems. Its proprietary process uses cryogenic (liquefied) air or its principal component,liquid nitrogen, as the working fluid and the medium for storing energy. Highview storage systems can be built with power from 10MW to over 200MW, and with storage capacity of 40MWh to over 2000MWh. A prototype 350 kW / 2.5 MWh Liquid Air Energy Storage pilot plant has been installed at the University of Birmingham Centre for Cryogenic Energy Storage.
A report Liquid Air on the Highway, presenting the environmental and business case for liquid air commercial vehicles in the UK, was published in 2014 by the Liquid Air Energy Network.
Pumped-heat energy storage (PHES)
Isentropic developed an energy storage system based on a reversible gas cycle which stores electricity in the form of thermal energy. The system is comprised of a hotand cold thermal store which are charged” and “discharged” by a reversible heat engine / pump.
A £15m investment by the Energy Technologies Institute (ETI) enabled a 150kW / 600kWh demonstration system to be constructed. The demonstration system was completed, commissioned and tested by a Newcastle University team. This pumped-heat technology potentially placed the UK as a leader in the R&D of low-cost and grid-scalable electrical and thermal energy storage.
Power to Gas
Power-to-gas includes electricity conversion, storage, and reconversion pathways that utilize gas for energy storage (hydrogen, ammonia, methane). This may be attractive where the stored energy has to be transported long distances before re-use, or where it may be flexibly integrated with other needs such as chemical feedstock or fuel for transportation or heating.
Siemens co-ordinated construction of an ammonia synthesis and energy storage demonstration system, at Rutherford Appleton Laboratory, and completed in 2018. The project was supported by Innovate UK and collaborators with Siemens included the University of Oxford, Cardiff University and the STFC.
Pumped Hydroelectric Energy Storage (PHS)
(Note that PHES is an alternative abbreviation that is sometimes used, however this may be confused with pumped-heat energy storage)
Pumped hydro storage accounts for the majority of all types of energy storage worldwide with total power 104GW in 2008, around 3 of generation capacity. Although in some geographical areas PHS may have limited potential for further deployment, many storage systems are under construction particularly in China, and a study published in 2018 identified pumped-hydro energy storage sites which have a global potential storage capacity of 22 million GWh.
Another possible application of gravitational energy storage is based on a simple principle: raising and lowering a heavy weight to store and regenerate energy. Like pumped hydro storage, the technology requires suitable geographic locations. Systems are being developed in the UK by Gravitricity and Escovale
Finally, there are several energy storage consultants in the UK, including EA Technology (who published a Good Practice Guide on Electrical Energy Storage and run the Energy Storage Operators Forum ESOF); Swanbarton Ltd (organiser of the International Flow Battery Forum); and Escovale Consultancy Services (publisher of a management report on Energy storage: Technologies, Applications and Markets).
Table 2.1: UK Capabilities
Table 3.1: Research Funding | Table 3.2: Key Research Providers
UK Research and Innovation (UKRI) brings together the seven UK Research Councils (including EPSRC and STFC), Innovate UK, and Research England, and works in partnership with universities, research organisations, businesses, charities, and government to create the best possible environment for research and innovation to flourish.
This landscape section mainly includes EPSRC funding, while Innovate UK funding is included in Section 4 Applied Research, and STFC funding is included in Section 7 Networks.
The UK Government’s Industrial Strategy Challenge Fund, delivered by UKRI, covers 15 Challenges of which two include energy and energy storage:
Faraday Battery Challenge (funding up to £246m)
Partly in response tothe plan for all new vehicles to be electric and zero emissions vehicles by 2040, the Faraday Battery Challenge will invest in research and innovation projects and new facilities to scale-up and advance the production, use and recycling of batteries. This will also help advance development of batteries for other applications.
Prospering from the energy revolution (upto £102.5m)
The aim is to link energy supply, storage and use, and to develop systems to support the move to renewable energy, and funding will be provided to industry and researchers. Energy storage is included in the scope.
Grid-scale energy storage was identified as one of the Eight Great Technologies to drive UK growth in the UK Government’s Autumn Statement 2012. In response to EPSRC’s Capital for Great Technologies Call, grid-scale energy storage received an EPSRC Capital Grant of £30m, with capital funding provided to 17 Universities for 5 projects. (See Section 6).
The EPSRC Energy Programme supports several areas of energy storage research, as well as SUPERGEN, Doctoral Training Centres, and the UK Energy Research Centre.
Large EPSRC funded projects, described in Tables 3.1 and 3.2 include:
Energy Storage for Low Carbon Grids, (EP/K002252/1),
Integrated, Market-fit and Affordable Grid-scale Energy Storage (IMAGES), (EP/K002228/1),
Energy SuperStore SUPERGEN Hub (EP/L019469/1),
Energy Storage Research Network (EP/J021695/1).
EPSRC funding has provided a strong research base in Universities, that has led to projects such as FLEXIS (Flexible Integrated Energy Systems), a £24m research operation part-funded by the European Regional Development Fund and supported by the Welsh European Funding Office (WEFO). Thisproject is developing an energy systems research capability, including storage within the Integrated Energy Supply Systems work package.
SUPERGEN is part of the EPSRC Energy Programme and is a key initiative in Sustainable Power Generation and Supply. It aims to contribute to the UK’s environmental emissions targets through a radical improvement inthe sustainability of the UK’s power generation and supply. The first consortia were launched in 2003, and the SUPERGEN Phase 3 (2011-2017) supported seven Supergen hubs with £150m of investment over a five year period (including challenge calls and Centres for Doctoral Training). The following Supergen Phase 4 (2017+) featured an enhanced management structure and wider multidisciplinary involvement of Universities. The seven SUPERGEN projects cover a wide spectrum of energy research and training and include the Supergen Energy Storage Consortium.
The 2013 Call for EPSRC Centres for Doctoral Training included energy storage within 14 priority areas. The EPSRC Centre for Doctoral Training in Energy Storage and its Applications started at the University of Sheffield and University of Southampton from 2014 onwards.
UKRI also provides funding for the UK Energy Research Centre (UKERC) and the Energy Technologies Institute (ETI); both include energy storage within their scope. After 12 years of research into low carbon technologies, the ETI is now closed. Available data and findings from the ETI’s programmes are available online through the Programme pages and Knowledge Zone until 2025, and the project results will also be available from the ETI Publications component of the UKERC Energy Data Centre.
Table 3.1: Research Funding
Table 3.2: Key Research Providers
Table 4.1: Research Funding | Table 4.2: Key Research Providers
Applied Research is funded by the UK Government primarily via Innovate UK, within the UK Research & Innovation (UKRI). Innovate UK was formerly known as the Technology Strategy Board (TSB) prior to 2014. Its role is to promote and support research, development and exploitation of technology and innovation for the benefit of UK business, in order to increase economic growth and improve the quality of life.
The UK Government’s Industrial Strategy Challenge Fund, delivered by Innovate UK and UKRI, covers 15 Challenges which include energy and energy storage:
Partly in response to the plan for all new vehicles to be electric and zero emissions vehicles by 2040, the Faraday Battery Challenge will invest in research and innovation projects and new facilities to scale-up and advance the production, use and recycling of batteries. This will also help advance development for other applications.
Prospering from the energy revolution (up to £102.5m)
The aim is to link energy supply, storage and use, and funding will be in industry and research to develop systems to support the move to renewable energy.
Table 4.1: Research Funding
Table 4.2: Key Research Providers
Table 5.1: Demonstration Funding Programmes | Table 5.2: Major Demonstration Projects
Table 5.1: Demonstration Funding Programmes
Table 5.2: Major Demonstration Projects
Table 6.1: Research Facilities and Assets
Table 6.1: Research Facilities and Assets
Table 7.1: Networks
Table 7.1: Networks
Table 8.1: EU Framework Programmes
Table 8.1: EU Framework Programmes