National Grid plans to stabilise the energy grid by plugging into new technology after raising concerns a year ago that it may be “walking blind” into the risk of blackouts.

The energy system operator is under investigation by the industry regulator, and the government, after Britain’s biggest blackout in more than a decade struck large parts of England and Wales on 9 August.

The system operator revealed that it had been running the risk of blackouts over a year before the outage, which cut electricity to almost a million homes.

To safeguard the system it has been working on a series of software agreements with companies including the US giant General Electric (GE) to replace its spreadsheet models, which provide estimates of the grid’s stability.

National Grid is understood to be close to announcing a deal with GE to measure energy system “inertia”, or the energy buffer that helps to keep frequency stable, following a separate deal with another technology firm for similar software in August.

A National Grid spokesman said the initiatives are the first of their kind anywhere in the world, and will be incorporated “over the coming years”.

The FTSE 100 company has invested about £10bn in modernising the grid over the past six years but industry sources fear that its efforts are not coming fast enough to adapt to the quicker-than-expected rollout of new energy technologies.

The deals have emerged after a senior National Grid executive revealed last July that the company was “walking blind” because it cannot measure the stability of the grid.

Duncan Burt, the operations head, said: “If we don’t know if the grid is secure, then we are walking blind into operating scenarios that we don’t understand well. Grid operators don’t like to do that because walking blind into those scenarios puts your grid at risk – it can increase the chance of power blackouts and failures.”

GE’s new technology works by collecting data readings 50 times per second to monitor changes in the grid’s stability, and by predicting the inertia needs up to 24 hours in advance.

Renan Giovanini, an analytics manager at GE, said the new systems will “help to reduce the likelihood of a blackout” by evolving the tools National Grid uses to assess the energy grid.

National Grid has blamed lightning strikes for triggering a series of power-plant outages on 9 August, leading to a sharp fall in the system’s frequency, which caused the blackout. It said low inertia can amplify the impact of outages by allowing the system frequency to fall faster than expected.

The energy system’s inertia is typically lower than it was 10 years ago following the move from large-scale fossil-fuel plants to renewable energy projects, which is making it more difficult to maintain healthy inertia and frequency.

A spokesman for National Grid said its systems “are appropriate” for the levels of wind and solar power in operation but the company plans to “embrace new technologies” by 2025 when it wants to be able to run a carbon-free system.

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