Energy storage has been identified by the main authorities for energy in the UK as a key solution for improving grid resilience and the development of a low carbon electricity grid.
Indeed it has been estimated that proper facilitation of storage technology could save the country billions of pounds.
Some distance has been travelled in terms of recognition for the industry but as Dr Jill Cainey of the Electricity Storage Network, who work closely with Government, regulators, and developers to advance the deployment of energy storage in the UK, explained to Power Engineering International, much work needs to be done in the areas of regulation and financing before that financial, environmental and energy security potential is realised.
To draw attention to the potential storage has, Cainey cites a paper in 2012 for the Carbon Trust delivered by Imperial College London Professor of Engineering, Goran Strbac.
In the paper entitled ‘Strategic Assessment Of The Role And Value Of Energy Storage Systems In The UK Low Carbon Energy Future’, Strbac looked at what he called ‘the benign dictator.’
“He said if there were 10 GW in storage, you would put that storage where it was technically best to go without any reference to National Grid or distribution network operators or anything like that. You simply put it where you needed it.”
“If you incorporated 10 GW of storage into the system (UK has 3 GW at the moment) by 2050 that would save the country £10bn.”
The newly initiated National Infrastructure Commission, a body set up by Chancellor George Osborne to provide more heft and vision in Britain’s infrastructure strategies, may give the technology the impetus it needs to secure that mammoth saving.
“Within the NICs strategic brief they are keen to see large scale storage fulfilled and (storage) has a specific place in their activities although the exact detail hasn’t yet emerged. It was part of their recent announcement.”
Storage solutions can provide a host of applications to improve the flexibility of the grid, help meet peak demand during the winter months, and defer non-essential grid upgrades. These applications can potentially support the grid throughout the year without being susceptible to price fluctuations.
For the UK, electricity storage projects in all categories are of interest, including compressed air, batteries, liquid air, pumped hydro and future technologies that will enter the equation.
The ESN has been busy in recent years looking at resolving the legal and regulatory issues that could scupper real progress.
“When the various energy system acts were written storage wasn’t included. So we have supply, distribution, transmission and generation but no storage. We now have interconnectors which have subsequently been added.”
“Because our electricity industry has been highly regulated, if you are already a regulated entity it becomes tricky to own and operate electricity storage because although charging storage is not a problem, when storage discharges it is either going to look like supply or it is going to look like generation. Specific entities can’t do that under their current license conditions. That makes it complicated.”
By way of example she points to the battery currently deployed by UK Power Networks at Leighton Buzzard.
“In order to get their battery on, and they have done it very by the book, one side of the battery is connected as a demand customer, and had to go through its connection process, charges and connection agreement and distribution of use charges. On the other side of the same device, which is at a distance of say 50 metres it has to be treated as generation connectee, connected on that methodology, with generation connection charges, along with distribution use and system charges. It is very complicated as you essentially treat your single asset as two different things”
Helpfully, UK Power Networks has released a report on the regulatory framework necessary for their Leighton Buzzard project and subsequent projects for not only DN0s but also for third parties. It talks about all the issues– the various low carbon incentive regimes and how a storage device is often charged twice, and, as Cainey puts it ‘all the little niggly things that happen because storage isn’t defined.’
Other recent developments include the National Grid’s call for expressions of interest in enhanced frequency response, DECC’s storage stakeholder steering group and the Smart Grid Forum, including OFGEM, which is about to produce a report on what exactly is required to move storage forward in the country.
TYPES OF STORAGE REQUIRED
The types of storage technology that make it to the front of the queue will vary.
“It’s difficult to say with so many different technologies with different features and scales. For instance National Grid with their enhanced frequency response service is looking for something that responds really rapidly but of a short duration of about nine seconds. They will be prepared to value any device that can do more than nine seconds and still respond quickly with a higher value and then for the evening peak issue you need something that’s got a reasonable duration – it could be a battery, be that Liquefied air energy storage or perhaps compressed air energy storage – you need a more grunty technology and there are resolutions that are tried and tested now.”
So what are the implications for the growing share of renewables in the system? Cainey says at the moment it is difficult to connect renewable generation because the network is constrained and also sometimes because it’s variable nature causes particular technical issues on the network.
“When the sun then goes down in the afternoon everything starts coming back on the system and that ramp up in demand causes problems. So if you put storage in the system you can help manage your connections. If solar generation at noon is causing overvoltage then storage can help you manage your technical issues with your wire and equipment and then you can release that out into the system later during evening peak.”
“Also if you have limited export connection, more than you get out on to the system you can store it on your device. Then if you don’t have enough it’s under your cap and you can top it up with your storage device. So you are always maximising what you can put on to the system and in certain situations it can even make you dispatchable.”
THE UP-FRONT INVESTMENT ISSUE
The main overriding concern for the future of a promising technology remains tied up in the extent of financing required to make it a true contender.
Cainey says even if storage does come down in price through innovations such as what it is being done with lithium ion batteries, any new technology must compete with large incumbent providers who are already on the system a long time.
“So the standard services that storage could also provide like short term operating reserve and standard frequency response, other incumbents can already do that so it’s very hard for a tech with high up-front investment costs to compete. So it’s about dealing with that upfront investment costs by providing an investment scheme or tax break or GIB input to get these on the system.”
Considering where it was even a decade ago, the technology has made progress and there is a sense with the NIC also expressing interest, momentum may continue.
“We have gone from Electricity Market Reform and capacity market and Contracts for Difference (legislations), none of which helped with storage, to a very broad recognition that we are going to need it and there are going to be things that have to be done in order to facilitate getting that storage on the system.”
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