West Sussex County Council has a long-standing commitment to action on climate change and has pledged to make the authority carbon neutral by 2030. In the past decade, WSCC has almost halved its carbon emissions and dramatically increased the amount of renewable energy it generates. It now produces more clean electricity than it consumes in delivering its core activities, excluding schools. This has been achieved through an ambitious programme to build solar farms on council land, integrate renewable energy technology into council buildings and enable more than 80 schools to switch to clean power.
Over time, WSCC has needed to adapt its renewable energy programme in the face of shifting energy policies and priorities.
When WSCC opened its first solar farm at Tangmere near Chichester in 2015, the availability of government feed-in-tariffs made the business case for investing clear and persuasive. The 5MW site, which was developed on surplus council land with no other use, produces clean energy for the grid and is capable of powering 1,500 homes. Over 20 years it will generate a projected £13.8 million from electricity sales and feed-in-tariffs and pay back the construction cost in less than 10 years.
The reduction and eventual withdrawal of the feed-in-tariff prompted a rethink as the authority developed plans for its second solar farm, a 7.4MW site built on a closed landfill at Westhampnett, near Chichester. The authority needed to explore new and different revenue streams to keep its renewable energy programme on track, while covering construction costs and delivering a return on investment.
Having explored a range of options, including establishing a ‘private wire’ arrangement to supply a local commercial energy consumer, WSCC developed a robust business case for a solar farm with a co-located 4MW battery system. The batteries would be used to store surplus energy and release it to the grid during periods of peak demand. Providing this service would generate revenue for the county council and support the grid to manage fluctuations in energy supply and demand which can be a feature of intermittent energy generation from renewable sources, such as wind and solar.
Westhampnett became the country’s first ‘subsidy free’ solar farm in public ownership when it opened in October 2018. The 26,000 solar panels generate 7,275MWh of clean energy each year, saving 1,681 tonnes of carbon dioxide from entering the atmosphere. It will also generate more than £5 million for the county council during the lifespan of the project.
The county council works with a private sector partner, Npower Business Solutions, to operate the 4MW battery installation and deliver the best operational and financial impact. Specifically, the batteries are used for:
- responding to periods of increased or peak power demand on the grid (demand side response)
- managing peak winter demand on the grid (TRIAD management)
- trading energy (arbitrage) by using the batteries to store power when it is cheap and in surplus and discharging to the grid when demand (and prices) peak.
An independent report commissioned by the county council from Cornwall Insight in 2020 concluded that this strategy is working well. The project also received a Special Award for Net Zero (highly commended) in the 2020/21 Association of Decentralised Energy Awards. Other data has shown the contribution that Westhampnett continues to make to grid stability by responding within seconds to power outages and disruptive fluctuations in frequency.
Beyond the environmental and grid stability impact, Westhampnett has provided direct support to the local green economy. A company based in Littlehampton, West Sussex, served as principal contractor for the project and the authority continues to seek out opportunities to work with local accredited contractors throughout its pipeline of energy projects.
Westhampnett and Tangmere solar farms have also enabled the county council to promote the role of local authorities in local clean energy generation with a range of audiences. The authority continues to host guided visits for groups as diverse as school children, university students and businesses people from the UK and overseas.
The county council has learned a significant amount from the experience of developing and operating Westhampnett solar farm. This knowledge and experience, particularly in relation to energy markets and potential revenue streams, has led to the development of and approval for the business case for a new standalone battery installation. The proposed 12MW battery site in Sompting, West Sussex, is expected to be operational in 2022. The batteries there will perform a similar role to those at Westhampnett in helping to stabilise the grid and enable further, intermittent renewable energy generators to come on stream.