RES containerised battery storage system. Image: RES.
A UK electricity distribution network operator has signed a contract with Renewable Energy Systems (RES) to deliver an energy storage system co-located with large-scale solar, which will be used to develop ways to commercialise services to the grid.
Announced on Thursday, a 300kVA/640kWh battery storage system will be installed at a 1.5MW solar farm site in the west of England near Glastonbury, site of the famous annual rock music festival. The solar farm is on the 11kV network of Western Power Distribution (WPD), one of the UK’s distribution network operators (DNOs) charged with maintaining stability and security of electrical grid infrastructure.
Although headquartered in Britain, RES has over 77MW/47MWh of operational or construction phase energy storage projects in the US and Canada in addition to 10,000MW of renewable energy projects constructed worldwide including large-scale solar and wind.
RES’ UK energy storage manager John Prendergast told Energy Storage News in an interview that the trial could be notable for a number of reasons. It is thought to be the most ambitious project yet in the UK to demonstrate the network services solar-plus-storage can provide behind-the-meter to the owner and operator of the solar farm, which in this case is British Solar Renewables, and to DNOs. The project will be able to provide nine different network services and how to commercialise them.
“The project will do multiple applications, extracting the value of solar in multiple different ways. The control system delivering that is our own in-house REsolve control system,” Prendergast said.
“Behind the meter, the first benefit to the developer is selling power at higher prices by shifting it to times of day when it is valued more highly in the wholesale market. The will become especially important as high solar production in the middle of the day depresses prices.”
On the other side of the meter, as has been stated before by commentators and experts including Rocky Mountain Institute, storage can provide “stacked”, or multiple, benefits. Prendergast said that the project will aim to show how commercial mechanisms could be developed for DNOs to procure grid services from storage, which at present in the UK and many other territories is so new a concept that it has not been put into the regulatory frameworks of energy markets.
Prendergast said the company was pleased to be demonstrating many of these applications at a co-located storage and solar facility, with the company’s work in storage in the US so far having concentrated on the frequency regulation and transmission and distribution upgrade deferral applications of storage in front of the meter.
“So say, the DNO wants to lop the net demand behind a substation that’s reaching a constraint it can buy a peak-lopping service from a storage asset sitting behind the constraint,” Prendergast said.
It will also assess how DNOs could buy voltage services to mitigate power quality issues from storage co-located with solar. In two or three years’ time, when the project has begun reporting back with data, it will aim to “have worked out the commercial arrangements” for procuring these types of flexible assets.
'Fully-wrapped' EPC and warranty arrangements
RES believes the project could be, if not the first, then among the earliest UK storage projects to be delivered to the customer as a fully-wrapped engineering, procurement and construction (EPC) package.
Batteries will be procured from Chinese-American manufacturer BYD, while RES is building the plant. It is also offering a “warranty-wrapped solution to WPD”, according to Prendergast.
“They are looking to us and to nobody else [for warranties] and we think that’s fairly unusual because often people tend to pass through manufacturer warranties and then the clients ends up looking to multiple people for warranties around different parts of the installations. We’re providing a fully-wrapped warranty because we’re confident with storage technology.”
Edging into the financial mainstream
Prendergast said that likewise, while it is still early days, financial institutions are starting to also become more comfortable with the idea of financing storage. In the US, financing for two projects by the company, the Jake and Ellwood large-scale storage systems in Chicago came from Prudential, for example, showed that “mainstream institutions” are becoming “quite comfortable with the technology, and not seeing it as a risky technology”.
He hoped that in parallel with the project’s two to three year demonstration period, activities by the UK government and network operators to look at storage and how it can provide flexibility to the network will combine to open up a viable market for storage in the UK at commercial and utility-scale. The project will be supported by the UK’s regulator Ofgem, in its Network Innovation Allowance programme and in addition to British Solar Renewables, the UK’s National Solar Centre will also collaborate on the project.
“The results of all of this work will hopefully combine to open up the market for storage and for flexibility solutions within the electricity system which are a really important part of how we move to a decarbonised electricity system at least cost to the consumer,” Prendergast said.
“I guess a lot of people in the UK market will see storage as something just really coming out of the R&D phase. We’re very much of the view that it’s proven technology and it’s ready to get into the market.”