Interestingly, in June 2020, several large power companies, including Centrica and E.ON, sent an open letter calling on National Grid to accelerate the deployment of smart electric vehicle (EV) charging infrastructure, energy storage and other flexibility services in order to manage the Grid more rationally. The utilities’ letter stated that a number of options existed to reduce its current reliance on curtailing renewables, from long-duration storage to industrial-scale demand response. They stated that EVs, smart electric heaters and home solar batteries “could all be providing services at this time if the right signals and instructions were being administered”. They added “flexible technologies and storage assets will be needed to integrate a higher level of renewable generation into the system to produce carbon savings. Harnessing the potential of these technologies is critical to ensuring green energy supply isn’t unnecessarily wasted”. https://www.greentechmedia.com/articles/read/smart-flexibility-could-slash-uk-coronavirus-curtailment-costs

Indeed, throughout the UK,local authorities and local companies are in fact steaming ahead with their own initiatives. See box below. In addition, the recent UK pressure group, 100percentrenewableuk, was also set up to press for these developments. www.100percentrenewableuk.org

Some examples of innovative flexible RE technologies

1.An Edinburgh company, Gravitricity, is planning to use disused coal mine shafts in Scotland to store renewable energy by using heavy weights. Surplus electricity at night would be used to lift weights to the tops of mine shafts. When electricity were needed, the weights can be allowed to drop by gravity turning turbines for power.

2, Flexitricity, partnered with Gresham House Energy Storage Fund,  is operating a 75 MWh battery storage site in Yorkshire. The lithium-ion battery storage site is trading in wholesale markets using the National Grid ESO’s balancing mechanisms. Energy Voice 15th May 2020 https://www.energyvoice.com/otherenergy/240736/uks-largest-battery-to-help-keep-the-nations-lights-on/

3. South Somerset District Council has built a 30 MW battery energy storage system. It works with a local company Opium Power to sell flexibility services to the grid generating income for the Council. Solar Power Portal 25th Oct 2019 https://www.solarpowerportal.co.uk/news/somerset_council_owned_battery_to_be_boosted_to_30mw

4. A Virtual Power Plant in West Sussex streamlines how low-carbon energy is generated, stored, traded and consumed. The £31m SmartHubs Smart Local Energy Systems project last year received £13m of funding through the Government’s Industrial Strategy Challenge Fund. The project acts as a demonstrator to facilitate the decarbonisation of heat, transport and energy across social housing, transport, infrastructure and private residential and commercial properties in West Sussex. Project partners include ITM Power, Moixa Technology, ICAX, PassivSystems, Newcastle University, West Sussex County Council and Connected Energy. Edie 27th May 2020 https://www.edie.net/news/8/West-Sussex-s–31m–smart–local-energy-system-to-progress-during-lockdown/

5. Orkney already has an operational smart grid generating more than 100% of its electricity demand via renewable energy sources. It is integrating a new Demand Side Management system with the existing grid to provide intelligent control and aggregation of electric heating systems in homes, businesses and council buildings, as well as EV charging points and hydrogen electrolysers. A distinctive aspect is that demand response services are delivered by a new local energy company, a consortium of local generators and other stakeholders. The system specifications and operating parameters are approved by the Grid’s DSO, which retains final oversight of the system, but day-to-day management is by the local company and its contractors. https://www.h2020smile.eu/the-islands/the-orkneys-united-kingdom/

For the future, at least two additional technologies below could also be implemented,

6. Heat pumps in conjunction with thermal storage to be operated when RE generated electricity is plentiful and demand is low. Denmark is looking at using CHP plants in conjunction with heat pumps and additional heat storage capacity to store surplus energy on windy days. Their district heating systems could absorb large quantities of surplus wind-generated electricity by using heat pumps and electric heaters for heating water. When demand for electricity is high but the wind is low, CHP plants could sell their electricity. http://www.pfbach.dk/firma_pfb/forgotten_flexibility_of_chp_2011_03_23.pdf

7. The same principle applies to electric vehicles using vehicle to grid technology. Central and local governments across UK have fleets of ~75,000 vehicles. If these were EVs, they could come back to depots with an estimated average 50% charge which could be sold back to the grid during the peak (red zone) period of 4.30 pm to 7.00 pm. They could then be recharged in the small hours ready for morning duties. (http://projects.exeter.ac.uk/igov/wp-content/uploads/2013/10/Lockwood-System-change-in-a-regulatory-state-paradigm-ECPR-Sept-13.pdf)

[1] This is in contrast with France. It obtains about 75% of its electricity from nuclear so that EDF in France must ramp up and down most of their reactors to follow diurnal demand patterns. But this is a risky practice, therefore for safety reasons most of the older 900 MW French PWR reactors are restricted to low burnup regimes (<25,000 MW days per tonne when designed for 33,000 MW days per tonne).