Renewables can re-power energy network in face of total failure, test shows

Traditionally, large power stations are used to energise the higher voltage transmission network in the unlikely event of a partial or total shutdown of the electricity system, followed by a ‘top-down’ restoration of demand at lower voltages.

The National Grid ESO conducted a trial in Galloway, south-west Scotland, which saw a hydro generator connected to the distribution network self-start, energise the local transmission and distribution network, and power up wind turbines on two wind farms within an isolated test network.

While there has never been a need to restart the electricity system from scratch, the success of the trial creates a blueprint for incorporating distributed, green energy sources as a tool for firing up Britain’s electricity system.

The three-year Ofgem-funded Distributed ReStart project has been trialling a ‘bottom-up’ approach by utilising renewables such as solar, wind or hydro, to fire up the electricity system. Its aim is to show how this process could restore demand to localised areas of electricity network in the event of a failure.

These tests proved the viability of connecting multiple facilities to a ‘weak’ islanded section of the electricity network, and now has the potential to be rolled out across Britain as a way to restore local demand in the event of a partial or total shut down of the electricity system.

National Grid ESO also said it would also save hundreds of thousands of tonnes of carbon emissions by avoiding warming conventional coal and gas power stations, while boosting its plans to be able to operate a carbon-free grid by 2025.

Julian Leslie, head of networks at National Grid ESO, said: “We have one of the world’s most reliable electricity networks, but our role is to be prepared for the most extraordinary of scenarios, including a nationwide power outage.

“This trial is a breakthrough moment for our Distributed ReStart project, which stands to improve system resilience and security of supply in a cleaner and cheaper way.

“We are always innovating for a greener future and the huge growth of green energy sources on distribution networks presents an opportunity to reduce our reliance on fossil fuels and co-ordinate a system restoration process using renewables.

“The concept of meeting our grid restoration needs by renewable generation alone has become closer to reality as a result of this trial.”

Scott Mathieson, network planning director at SP Energy Networks, said: “The increasingly complex needs of our energy system, coupled with the significant increase in both demand and generation we need to accommodate on our transmission and distribution network, mean it is crucial we ensure the continued security and resilience of our electricity system.

“We’re really encouraged by the results of this latest trial on the Distributed ReStart project, where we’re seeing a real opportunity for this innovative approach to improve resilience and timelines for system restoration.”