EPG at SolaStor 2016

Joel Atkin's picture

On Tuesday 14th April a group of us, made up of three EPG members and two colleagues from the IMMDS/ESS project, headed to Imperial College London to attend the SolaStor conference. SolaStor is a joint venture between two Supergen Hubs created by funding from the Engineering and Physical Sciences Research Council (EPSRC); the Energy Superstore and the SuperSolar Solar Energy Hub. These two hubs bring together researchers from 11 universities, and various industrial partners and government bodies. As Professor Nigel Brandon of Imperial College London pointed out in his opening address, the Energy Superstore is complimented by a programme of around £30 million of EPSRC funding for grid-scale energy storage research, in which the EPG holds a small share. With photovoltaics being a hot topic worldwide (and here at Oxford) I have no doubt that the SuperSolar hub also has a large amount of financial clout behind it as well.

Andy Boston of the Energy Research Partnership kicked off the day, speaking about system-level considerations for flexibility and balancing in renewables. The thing that seemed to strike the audience the most was Andy’s sounding of the death-knell for the levelised cost of energy as a useful approach, calling it too negative and singularised as a value. He suggested that we should instead be looking at the value of technology; the technology’s addition to the existing mix and the grid services it provides or facilitates.

Next up, Prof Goran Strbac of Imperial College London gave a very interesting talk on the value of energy storage in the context of rooftop/community-scale PV. Prof Strbac noted that infrastructure utilisation is predicted to degrade over the next 15-plus years to a point at which we have double the asset base for the same energy usage. As we gear more towards small-scale energy storage there are more opportunities for flexible technologies which are in turn key for increasing generation and reducing cost.

Julian Leslie of National Grid spoke about the integration of solar into the grid, noting an ongoing transformation in the energy landscape of decarbonisation, decentralisation (PV, wind) and digitisation (engagement of users and smart devices). The continuation of the first trend relies on innovation in the second two; there is a need for innovative tools services and control systems to cope with the increase in asynchronous generation capacity which currently stands at 20GWh per year, predicted to rise to approximately 60GWh by 2035.

A first insight into pre-market technology was given in Dr Anna Hankin’s talk. Her research at Imperial College London is focussed on the design and development of photo-electrochemical reactors for the generation of hydrogen Taking influence from photosynthesis, Dr Hankin is attempting to show that a PEC reactor’s high solar-to-hydrogen conversion efficiency makes it a key technology for future energy generation.

Next, Prof Ralph Gottschalg of Loughborough University gave an update into the state of solar technology research. He noted that costs need to continue to come down and integration issues need to be solved in order to further increase the viability of the technology. He also noted that the research landscape of PV had moved from crystalline silicon and thin film active layers towards work on perovskites and, to a lesser degree, system aspects of PV. Prof Gottschalg also noted the durability issues with PV, stating that the industry aim is 40 years and a lot of the technology currently starts to see problems at 6-7 years.

NREL Chart of Best Research-Cell Efficiencies for solar (click to see full version on NREL site). This plot is courtesy of the National Renewable Energy Laboratory, Golden, CO, USA.


An update into research into storage technologies was given by Prof Brandon, who went over the many advantages and disadvantages of lithium-ion, flow batteries and supercapacitors. He noted that it is prudent to decouple power and energy for cost-efficiency purposes and that for most applications we need both power and energy so this gives many possibilities for energy storage. Looking to the future, there appears to be exciting research opportunities for sodium-ion as an equivalent to lithium-ion.

Michael Simpson of the University of Nottingham gave an overview of the economies of scale of compressed air energy storage (CAES) and how the energy is stored before conversion to electricity. This was followed by John Prendergast from Renewable Energy Systems, a spinout from McAlpine, speaking about the growth of the storage industry and giving an overview of the business case for storage integrated with solar.

Before closing remarks by Prof Mike Walls of the SuperSolar Hub, Dr Murray Thomson of Loughborough University gave a summary talk of the role of storage in the UK grid which took the audience around finding the optimum capacity-to-power ratio for a high renewables scenario and looking at the relative costs of power and energy for different storage technologies.

Overall the SolaStor conference was a great experience for the 100-odd attendees, providing some excellent insights into the work going on in and around the two SuperGen Hubs. The Oxford team were extremely grateful to be invited along and thank the organisers for their hard work in putting together the event.