Craig Dyke, from National Grid’s electricity system operator, said batteries were being overlooked by Britain’s network operator up to 30 per cent of the time when they are cheaper than other power sources.
He said that technical factors such as outdated computer equipment and insufficient cables to send electricity where it is needed caused the problem.
The company plans to reduce the rate at which batteries are sidelined to single figures by early next year, calling current levels “higher than where we want them to be”.
Dyke’s comments were in response to a letter from four leading battery storage groups, which claimed National Grid’s “electricity system operator” or ESO division was making the country’s power costlier and dirtier by not using their technology correctly.
“Consumers are paying more, clean renewable energy is being wasted, and fossil fuel generation is being used instead,” they said.
The groups alleged that batteries were being overlooked up to 90 per cent of the time, favouring gas-fired power plants which emit tonnes of carbon dioxide and can be more expensive to run.
Dyke said the ESO had investigated the 90 per cent claim and found it valid at one battery unit on one day.
The four groups are Zenobe, Field Energy, Harmony Energy, and Eelpower.
The dispute highlights the challenges facing Ed Miliband, the energy secretary, as he aims to cut emissions from electricity generation to net zero by 2030.
Although the UK is the world’s second-largest offshore wind market after China, its wind farms are wasted when it is too windy and the grid cannot send their power where it is needed.
During such times, the ESO pays wind farms to switch off and may also pay gas-fired power plants to turn on, costing hundreds of millions of pounds annually, passed on to household and business energy bills.
Successive governments have encouraged developers to build dozens of battery storage facilities across the UK over the past decade.
However, the companies say the ESO is consistently underusing or “skipping” batteries, depriving them of revenue and undermining investor confidence.
“Even when batteries are the cheapest and fastest solution to meet the needs of the GB grid, the ESO favours more expensive options too frequently,” the companies said in the letter.
“Our own data, verified by the ESO, shows that batteries are being skipped over 90 per cent of the time during constraint periods for some sites.”
Dyke said batteries sometimes had to be overlooked because it was impossible to get their power where it was needed.
He acknowledged that they were also not used at times because the ESO’s computer systems made it hard for grid operators to be sure they had enough charge to supply the right amount of power.
However, Dyke said these so-called skip rates had decreased in recent months following a computer system upgrade in December 2023 and aim to reach low single-digit figures early next year following further planned improvements.
The upgrades should allow grid engineers to better estimate battery charging levels at individual sites, making them more likely to use their power when needed.
Dyke denied any cultural resistance within the business to using newer battery technology rather than conventional gas power plants.