The pioneering projects, worth £750 million, will be used to bank green power when it is plentiful and then provide electricity on demand when need is high or generation is low – such as at times when the wind isn’t blowing or the sun isn’t shining. The three projects have a combined capacity of 1GW, with the ability to store 2GWh of green electricity – sufficient to supply 2.7 million households for two hours.
In Scotland, the amount of energy generated from wind, solar, marine, hydro and biological sources is sufficient to supply almost all of the country’s domestic demand – around 97 per cent. However, renewable generation is considered less reliable than fossil fuel power due to its intermittency.
The giant batteries are being installed at substations at Blackhillock in Moray, Kilmarnock South in East Ayrshire and Eccles in the Scottish Borders, locations chosen for their proximity to important transmission networks. Their deployment will help stabilise the grid as an increasing amount of renewable energy comes online, a role currently performed by fossil-fuel power plants, and reduce the need to shut down wind farms when the network is overwhelmed.
The projects will slash an estimated £1 billion off consumer energy costs over the same period through a number of savings – including avoidance of high payments for gas and constraint of wind farms when their power cannot be accommodated. The developers say the storage will also help the UK achieve energy independence.
Meanwhile, the sites will save up to 13.4m tonnes of carbon savings over their 15-year lifespan. That’s equivalent to taking 490,000 diesel or petrol cars – more than the total number in Glasgow and Edinburgh – off the road over the same period.
The Scottish schemes, by international electric vehicle fleet and battery storage specialist Zenobē, will deliver the world’s first contracts for stability services using transmission-connected batteries. Their rollout will make the UK-based firm the largest provider of battery-based transmission solutions in Europe, and provide Scotland with the most advanced technology to manage renewable power globally.
“Zenobē is transforming the uptake of clean power, enabling the UK to become both more independent and greener in how it generates electricity,” said company co-founder and director James Basden said: “These projects are using the latest technological innovation to make renewable energy more reliable and affordable at a national scale.
“This is the future for how utility-scale battery projects will work on every grid. Our projects at Blackhillock, Kilmarnock South and Eccles are world-firsts for battery storage, addressing a key, complex hurdle to the uptake of renewables in an innovative way and pushing forward our progress to energy independence and a zero-carbon grid.
“At a time of increasing energy prices and the need for greater energy security, this is the type of investment which the UK needs now to drive growth, and which will enable both the country and Zenobē to become leaders in delivering the energy transition.”
Julian Leslie, head of networks at National Grid Electricity System Operator (NGESO), said the utility company was working hard to enable the UK to have a carbon-free power network and innovations such as the battery facilities mark “a turning point” in the move to green energy.
“Working with the industry we have developed contracts that accelerate the rapid uptake of renewable power,” he said. “These contracts are part of the solution that will enable NGESO to have the ability to operate a zero-carbon system in 2025.
“Investment into the use of new technologies by innovative companies like Zenobē is bringing this ambition nearer. The investment into these three major projects represents a turning point in how major grid-scale battery storage can support the grid as fossil fuel generation is phased out.”
Construction has already begun at the Blackhillock site, with the facility due to go live in early 2024. This follows the firm’s 50MW battery project at Wishaw, which was the first to win a constraint management contract from National Grid and will be the first in Scotland to connect directly to the transmission network when it goes live next year.
Renewable energy sources interact with the electricity grid differently from coal and gas plants. Fossil fuel power plants deliver certain key grid services – such as short-circuit level, reactive power and inertia – as a by-product of their normal operations.
Short-circuit level maintains system voltage during a fault. Inertia, which is derived from the kinetic energy stored in rotating turbines, prevents sudden changes in system frequency. Renewable power sources do not provide these services consistently, so to decarbonise successfully it is necessary to find alternative, reliable sources of grid stability.