Written evidence submitted by the UK Energy Storage Hub Oxford (REV0059)
Submitter
I direct the UK Energy Storage Hub (SUPERGEN), which represents and brings together all energy storage research in the UK across all stakeholders, including academia, industry and other public bodies. I also lead the energy storage research within the newly created Sir Henry Royce Institute for Materials at Manchester (£230M investment). For more than 25 years I have been a world leader in research into energy storage technologies.
It is now accepted widely that if the UK is to decarbonise the electricity and transport sectors, energy storage will be essential. A recent report from Imperial College indicates that the potential savings in the operation of a decarbonised grid by deploying storage could reach £8B per annum in 2030.
Although storage technologies are essential for a low carbon future, none are currently fit for purpose; they do not deliver the performance and lifetime at the cost required. Some storage technologies are available today and will be deployed over the next few years but the aforementioned limitations mean that the UK is facing a storage gap that will only be bridged if we can achieve innovative new generations of storage technologies.
The UK has an exceptional world-class science base with a track record of creating new ideas and making new discoveries with the potential to lead to new and successful technologies. The key enabling invention that led to the commercialisation of the lithium-ion battery (30 billion sold worldwide in 2015 alone) was made in Oxford. We need to invest and capitalise in our excellence in discovery and invention to develop new generations of energy storage technologies.
Three examples of where innovation in energy storage is possible that could change the game. Most of the innovations in energy storage will be driven by research on materials.
Lithium-ion batteries are already a major commercial success. To store electricity on a low carbon grid and to deliver transport with a driving range in excess of 300 to 400 miles will depend on research on new electrode and electrolyte materials. Exciting breakthroughs are being made in new low-cost electrodes for Li-ion batteries based on iron and manganese oxide materials that store significantly more energy than those currently available, making possible a new generation of high energy lithium-ion batteries. If we could replace the flammable and volatile liquid electrolytes used in current lithium-ion batteries by solid electrolytes, thus enabling all solid-state batteries, this would be transformational in safety, energy density, lifetime and cost. Together, the innovations described here could bring the cost of lithium-ion batteries below $100 /kWh, a tipping point in the adoption of energy storage.
Sodium is orders of magnitude more abundant than lithium and distributed throughout the planet, whereas lithium is located in often politically sensitive regions. Sodium, as a consequence, is a much lower cost material than lithium. Sodium also enables the use of lower cost materials, such as aluminium rather than copper to connect electrodes together within the batteries. There is currently no commercial sodium-ion battery. Research is needed on electrodes based on low-cost iron and manganese materials and new low-cost electrolytes, preferably based on solids permitting the development of all solid-state sodium-ion batteries. If the sodium-ion battery can be developed it could radically reduce the cost of storage. This ambition is well within the grasp of UK science.
Whereas lithium and sodium batteries deliver their best performance for storage requirements in the range 10 kWh to 10 MWh and for durations of seconds to hours, redox flow batteries offer even larger scale storage hours to days. Current devices use the vanadium, which is expensive. There is exciting research in the UK aimed at the development of new redox flow batteries based on much lower cost, organic materials to replace vanadium. Ion-selective membranes are also an important component and the discovery of new membranes is critical to reducing cost.
In contrast to the past, the UK now has the facilities to scale up prototype and demonstrate lithium and sodium-ion battery technology.
April 2016