When the wind blows too strongly operators are currently paid large sums of money to switch their turbines off – with the cost being borne by the bill-payer.
This is neither satisfactory to the consumer, or the Government, and is driving efforts to develop large-scale, energy storage systems.
Earlier this year six batteries of varying size, including a 5MW one in Darlington with the capacity to provide electricity for thousands of homes, were linked to the grid.
The aim of the trial – the largest of its kind in Europe – is to test the effectiveness of storage systems as the grid moves from being a top-down, supplier-led system to a smarter consumer-led one.
Ian Lloyd, network technology project manager at Northern Powergrid, the electricity distribution network operator for the North East and Yorkshire, said: “If the trials prove cost effective, storage batteries could be one way of shifting and smoothing out peak demand on the network.
“In the middle of the day there is less demand on the network, batteries simply pick up this unused energy and store it until there is a period of peak demand on the network. It’ll then discharge it on to the network to support these periods of peak demand.”
The Electricity Storage Network (ESN) trade association, whose members include the National Grid has urged the government to set a clear target to install an additional 2GW of storage capacity by 2020.
It says this will require an investment of £4bn, but potentially save £3bn per year by 2020 and therefore provide a cost-efficient way of balancing the increasing amount of renewable energy capacity that is coming onto the grid.
Last year Chancellor George Osborne said he wanted to make the UK a “world leader” in energy storage, hailing the technology as key to boosting the market for electric vehicles and enhancing the UK’s energy security.
In that respect the Government has been active in supporting the development of storage having recently invested in a number of technologies, while the most common existing form is pump storage – or hydro-electric power.
Andrew Crossland, PhD fellow and researcher in Home Energy Storage at Durham University highlighted how the first UK trial to store wind energy recently got underway in Norfolk recently.
The Northern Powergrid battery storage trial is part of larger North East project known as the Customer-Led Network Revolution (CLNR).
Its key partners are Northern Powergrid, British Gas, EA Technology, Durham University and Newcastle University and it is being part funded by Ofgem’s Low Carbon Networks Fund.
The £54m project aims to understand how the use of low carbon technologies, such as solar panels, electric vehicles and heat pumps, impact on the current electricity grid network.
The project involves the trialling of smart grid solutions on the electricity distribution network as well as creating smart-enabled homes to give customers more flexibility and choice over the way they use and generate electricity.
Findings from the project will provide guidance on how to meet the UK’s future energy needs via the deployment of smart grid technologies and help the industry ensure the UK’s electricity networks are prepared for the mass introduction of low carbon technologies.
Lloyd said: “The target is to reduce carbon levels in the UK energy mix by 80% by 2050, and to achieve that energy storage will have a major part to play.
“This is the future challenge to the distribution networks and the power generators. The network was previously a top-down arrangement, fit and forget, but it is changing to a more dynamic one, a smarter one, and one which makes the installation of storage capacity essential.
“The UK network will not be transformed by one big fix, there will be a lot of different technologies which will assist in the low carbon transition.
“The trial is looking at the cost of storage in the short and medium term, and we are trying to understand what benefits storage can give us? How we control it? And how we can optimise it?
Lloyd continued: “How would we cope if large numbers of electric vehicles were all recharged at the same time as people come home from work and put lights, heating and cooking on? We are already facing tighter supply issues. As things stand there are lots of unknowns in the way the powergrid is changing. The CLNR is helping us monitor and understand what the constraints and problems are.
“Batteries are a known and safe technology, they can be easily maintained, and consist of electronics we understand and we already know how they can be secured. There are lots of benefits but as things stand they are still too expensive.”
Mark Whitehead, partner and head of the energy team at Newcastle law firm Ward Hadaway, said: “Energy storage may be an oxymoron, as in theory energy cannot be physically stored, but can be converted from one form to another. Understanding this principle makes it easier to see how energy storage could be one of the significant industries of the 21st century.
“As power generation moves to a less predictable system via renewables, a range of technologies already exist to allow us to store power, including chemical and electro-chemical processes, physical methods such as pumping water uphill for future release into a hydroelectric system, or by a variety of more complex hybrid measures.
“The technology exists, and in many cases has done so for decades, for instance the ability to create hydrogen via electrolysis of water. To date the issue with scalability has principally been one of a lack of commercial imperative rather than a technical issue, although it is likely that subsidies may be required to drive interest in the market.”
Crossland added: “The main energy storage in the UK is large-scale pumped storage. Realistically, this is where the big ticket energy storage money is and will always be the most cost effective way to store large amounts of energy and they are currently being used to manage wind variability.”
North East energy storage trial
Six energy storage devices have been installed, commissioned and switched on by Northern Powergrid as part of a cutting-edge trial of electrical energy storage technology.
The devices have been placed on the live electricity network, across a mixture of rural and urban locations in the North East and Yorkshire to help balance the supply and demand of electricity for thousands of residential and business properties, and test the effectiveness of energy storage batteries as part of an overall smart grid solution.
Combined, these locations offer a representative sample of 80% of the UK’s electricity distribution networks and therefore, if the technology proves to be a cost-effective alternative to network reinforcement, it could be applied across 80% of other UK distribution networks.
Three of the devices have a capacity of 100kW, two are 200kW and the largest has a capacity of 5MW, making it one of the largest currently in operation in Europe.
Ian Lloyd, network technology project manager at Northern Powergrid, said: “What makes this trial of energy storage unique is both the size of our largest battery and the fact that, for the first time, we will be monitoring all six of the batteries and the networks they are on through an active network management control system.
“This has been uniquely developed for the CLNR (Customer-Led Network Revolution) project and will allow us to see in real time when and where we need to release more energy as well as giving us autonomous control of all other on-going CLNR trials.
“We’ve deliberately sited the storage devices at different points on our network, in a range of rural and urban locations to paint a comprehensive picture of how the technology works across various geographies and demographic makeups.”
The largest 5MWh device has been installed in Darlington and is helping to meet the energy demands of 14,000 different homes and businesses in and around the city. In comparison, one of the smaller batteries is supporting around 300 residential homes in Maltby, South Yorkshire, which has a high concentration and cluster of customers with solar PV technology. Another two batteries are in Darlington and the remaining two are situated in rural Northumberland.
Lloyd added: “We’ll be monitoring all six devices throughout 2014 to understand the role that energy storage technology could play as part of a range of innovative smart grid solutions that help us avoid the need for network reinforcement, improve network efficiency and support the uptake of low carbon technologies.
“Customers across these networks won’t notice any changes in their energy supply, but are playing an active role in helping us explore new ways to tackle peak energy demand and support the widespread adoption of low carbon technologies.”
Current and proposed energy storage technologies
The UK currently has 3GW of pumped hydro storage from four plants, which play a key role in balancing the country’s electricity system.
These are located in North Wales and Scotland and plans were recently unveiled for the expansion of the 440MW power station at Cruachan, near Oban, which could see it generate over 1GW of electricity.
When there is a surplus of electricity, water is pumped from Loch Awe to a reservoir on the mountainside and when demand is high, the water is released, generating electricity by driving turbines in the power station below.
The Dinorwig Power Station is a 1,728 MW pumped-storage hydroelectric scheme, near Snowdonia national park, north Wales.
Dinorwig is operated as a STOR (Short Term Operating Reserve), providing a fast response to short-term rapid changes in power demand or sudden loss of power stations.
In the last year the Government has been active in supporting new developments in the storage sector.
It awarded an £8m contract to a partnership of Viridor Waste Management and Highview Power Storage, of Slough, to fund the development of a technology to store air in a liquid format, which can then be used to supply electricity at times of high demand.
Electricity is used to take in air, remove the CO2 and water vapour, which would otherwise freeze solid. The remaining air, mostly nitrogen, is chilled to -190C and turns to liquid and stored.
When demand for power rises, the liquid is warmed and as it vapourises, the expanding gas drives a turbine to produce electricity.
The Department of Energy and Climate Change (DECC) has also awarded worth £3m to EValu8 Transport Innovations, of Hertfordshire, to develop a new storage system, partly made out of recycled batteries from electric vehicles that will store renewable energy generated at times of low demand for use at times of peak demand.
Contracts worth over £5m have been awarded to REDT UK, of London and Moixa Technology, as part of DECC’s innovation competition to support energy storage research and demonstration.
REDT UK has developed a technology to store electricity from wind turbines, and Moixa Energy has developed small battery-based storage units which could be installed directly into people’s homes to store power and re-use it at times of peak demand.
Global power giant ABB commissioned its first DynaPeaQ energy storage installation for at a site in Norfolk. Its lithium-ion batteries store energy generated by local wind turbines when power generation exceeds the demand on the distribution network.
Ian Lloyd said: “There are many different methods of energy storage under development but at this stage we know more about battery technology. Batteries are portable, robust, easy to maintain.”