Photo © Harmony Energy
Wind turbine and solar panel methods of electricity generation may be familiar to many, but the role battery energy storage systems (BESS) play in supporting renewables is perhaps less well known. By storing electricity and releasing it during peak demand periods, BESS help offset the intermittency of these forms of generation.
BESS uses intelligent built-in technology to communicate with the grid to know when to charge and discharge the energy stored, acting on variables such as energy demand and price fluctuations. Given its quick response times BESS can also provide ancillary services such as critical grid stability support.
For instance, automatic frequency restoration reserve is initiated to respond to frequency deviation – an imbalance between supply and demand – in the grid. It is critical that frequency deviations are dealt with as they can lead to loss of efficiency, interruption to services and, on the more severe scale, damage to equipment and blackouts.
A developer can also colocate its BESS with another renewable, most commonly solar. This can improve viability by gaining the benefits of both generation and storage offering funders and developers flexibility with the benefit of different revenue streams.
Yet although public sentiment towards renewables is improving, projects are still met with local resistance during the planning process. Former colliery sites offer one way to integrate regeneration with BESS, providing a neat solution to the issue of repurposing these vacant sites.
Why are former colliery sites a good choice for developers?
Former collieries can be an attractive choice for BESS. Not only do they offer large open areas, by repurposing such brownfield sites these projects improve the chances of receiving planning permission while mitigating potential opposition to schemes.
The National Planning Policy Framework aims to enhance these sites with the implementation of biodiversity net gain (BNG) schemes. These can take the form of planting wildflower meadows, hedgerows and trees to protect habitats and creating access corridors vital to wildlife. Developers will also try to minimise disruption to local ecosystems in their construction design and method plans.
A further advantage is sites' proximity to existing infrastructure, such as cables, associated substations, industrial water supplies and access roads suitable for heavy vehicles to transport equipment, all of which will reduce construction costs and time.
Not every colliery site may be suitable for BESS, however. Many factors are required for a successful project, including:
- grid capacity. Capacity may have been reached, significant engineering works may be required for the new connection or simply securing the connection in a long, oversubscribed pipeline of connection requests may be tricky.
- the topography of the site. BESS requires a lot of flat space to house the batteries with their invertors, transformers and switchgear, substations and integrating the electric cables in the ground, all requiring solid foundations, which colliery sites sometimes lack. Civil engineering is key to ensuring BESS projects can be built to the optimal requirements. While modern engineering feats can transform problematic ground conditions into stable foundations, the feasibility often comes down to the developer's financial resources.
- general planning requirements such as visual impacts, flood risk, as well as groundwater contamination considerations, and safety.
What to consider when repurposing former colliery sites
There are some key considerations from a real-estate perspective when repurposing former colliery sites.
- Other projects: the popularity of former colliery sites given the available infrastructure and the preference for development on such sites means there is often more than one energy project sharing the grid; former colliery sites have also been repurposed for natural gas production, for instance. A second development may require permission from the first if it infringes on the rights granted to it, such as cable easement corridors to the point of connection or access to highways. While a legal agreement can often be reached, there may be wider implications where an energised site needs to shut down for safety to permit secondary works and the financial liabilities of this considered.
- Title considerations: many sites were owned by the National Coal Board, which became the British Coal Corporation before being privatised. As a result, there are many legacy rights pertaining to past land transfers and amalgamations. The title needs to be reviewed to ensure there are no adverse interests affecting the proposed development. Easements and rights can also be extinguished when titles are merged under one ownership. Mines and minerals are often excluded from the landowner's title, opening a risk of trespass if the development requires excavation. As energy projects go through funding rounds or are sold between developers to strengthen portfolios, they come under heavy scrutiny at a reporting and due diligence phase, so it's essential to ensure no title issues are left unaddressed. Standard insurance policies can deal with many defects in title such as access rights, historic restrictions or mines and minerals being excluded from the landowner's title that are acceptable to a funder or prospective buyer. In some instances a more bespoke insurance solution may be more suitable.
- Search results: although colliery sites benefit from proximity to existing infrastructure, this can also mean underground services are also present. Developers will want as much information as possible relating to any existing underground cables and pipes, as well as overhead cables. While they will carry out their own ground investigations at option stage, these will be more effective when supported by records of existing service media to help predict where is best to carry out the surveys such as ground-penetrating radar surveys. Developers need the construction design and cost to factor in whether current services can be diverted or removed where they will interfere with the project or whether they can be built over. Legal rights will need to cover all possible eventualities so that developers can implement the BESS as intended.
- National requirements: given all the benefits of former colliery sites, they may also be subject to a compulsory purchase order for national infrastructure. For example, National Grid's Eastern Green Link 1 (SEGL1) anticipates heavy construction at Hawthorn Pit in County Durham. National Grid echoes the above benefits in its choice of site. As covered above, there are often instances, due to limited suitable land options and points of connection, where multiple energy developments will need to overlap. In these scenarios developers need to work together to ensure each project is suitably protected and can operate independently of the other. The developer can also reconfigure their construct design to try and mitigate or work around any foreseeable issues caused by an existing or planned development.
Although there are legal, planning and development challenges to overcome, former colliery sites can offer huge potential, turning symbols of a fossil-fuelled past into the foundations for a sustainable energy future. Vital to the transition to a greener grid, BESS need plenty of physical space and colliery sites are one solution. With the advancement of technology and AI we can only expect BESS to become more efficient and hopefully offer greater storage capacity and use while limiting its construction footprint.
Projects demonstrated BESS potential
The following offer some examples of energised or in-construction BESS projects on former colliery sites:
- Hawthorn Pit, County Durham
- Coalburn phase 2, Scotland
- Ferrybridge, West Yorkshire
- Richborough Energy Park, Kent
- Uskmouth, south Wales.
Ben Finley is senior associate solicitor in the real estate team at Blacks Solicitors
Contact Ben: LinkedIn
Related competencies include: Compulsory purchase and compensation, Contaminated land, Energy and renewable resources, Engineering surveying, Environmental management, Legal/regulatory compliance, Management and regeneration of the built environment