Our Blog


Published: 04 October 2017
Sector: Energy

Co-location of solar and storage – will ROC accreditation be kept or lost?

Last month UK developer Anesco announced that Ofgem had confirmed that three of its solar farms that have been accredited for Renewable Obligation Certificates (ROCs)  and which are connected to batteries through shared grid connections could retain their ROC-accredited status.  The decision is, according to Anesco, a “game changer for the UK’s energy storage market”.
However, Ofgem has made clear that the question of whether co-location of storage and solar will entitle the solar farm’s ROC-accreditation to be retained is one that will be decided on a case-by-case basis. Ofgem is currently preparing draft guidance on the issue.   
Eligibility criteria for developers

In order for a renewable energy power plant to be eligible for ROCs, it must meet certain eligibility criteria.  These are explained in Ofgem’s Renewables Obligation: Guidance for Generators that receive or would like to receive support under the Renewable Obligation (RO) scheme.  The eligibility criteria include requirements that the fuel source is renewable, that the electricity is supplied to customers in GB and or Northern Ireland or is used in a “permitted way” and that there is proof of how the electricity is generated and metered.

How will this work in practice?

Co-location of a battery storage facility on a solar farm could be problematic in terms of ensuring that these eligibility criteria are still complied with.  For example, if some of the electricity from the solar farm is used to charge the battery and that is then exported to the grid, can it be said that this electricity is being supplied to customers in GB and/or NI?  Arguably, if the only electricity that the battery exports to the grid is that supplied by the solar farm then it would be reasonable to argue that this requirement is being met.  But what if the battery is also importing power directly from the grid?  In that scenario, the “green energy” from the solar farm is being mixed with “brown energy” and it is more difficult to say that the electricity from the solar farm is being supplied to customers in GB and/or NI. It is also arguable that energy which is a green/brown mixture is not energy where the fuel source is renewable.
Another possibility could be for the solar farm operator to sign a “permitted ways” declaration that the electricity from the solar farm is generated and used on-site by the operator of the generating station.

Another issue to be considered is how electricity which is supplied from the solar farm to the battery and then exported is metered.   
Game changer perhaps  – but developers will need to need to take each game as it comes and await the referee’s decision.

Solar developers looking to co-locate a battery storage facility with a ROC-accredited solar farm run the risk that this will be treated as a material change to the generating station and cause the ROC-accreditation to be lost.  This is obviously a major risk and Ofgem’s guidance on this subject will be keenly-awaited. However, developers who hope that the guidance will give a clear roadmap to ensuring that co-location can be done in such a way that ROC-accreditation is not lost are likely to be in for a disappointment.  Whilst Ofgem are no doubt keen to encourage the growth of battery storage in the UK, it is likely that developers will need to take their own advice and make their own decisions as to the likely consequences before embarking on the development.

"This is exactly why we like to work with people who understand the industry and can identify potential issues and create solutions."

Jon Saltinstall, Senior HealthCare Banking Consultant, Lloyds Bank