February 4, 2021: More storage will be needed to improve the reliability and cost of renewable sources of electricity in the UK after the National Grid issued four warnings this winter that security of supply was at risk. It is the first time the network operator has had to issue such a warning in four years.
National Grid was forced to pay a staggering £4,000 ($5,500) /MWh at one point in January, only for it to plummet to just £50/MWh within half an hour, according to the infrastructure management services firm Px Group.
“When the weather conditions aren’t favourable for renewables such as wind and solar, the National Grid has to rely on more traditional ‘peaking’ supplies of energy and our interconnectedness with Europe,” said David Henderson, chief commercial officer with Px Group.
“Both our ageing fleet and competing pressures in other countries for electricity supply can lead to tight system margins, which cause prices to rise and consumers may see this passed on to them.”
To avoid blackouts, the UK pays units to make capacity available when the system is running low.
“Coal power plants do need to be ‘warm’ to provide power,” says Matt Magill, operability strategy manager with National Grid. “Each power station has its own way of ensuring ‘warmness’. This information is provided to the ESO through their dynamic parameter instructions.
“If a unit is not intending to run it will make this clear through its submissions for those units (generally coal) we can sending a warming instruction ahead of time to ensure the unit will be available if required.
“For managing the winter peak issues the government initiated the capacity market in 2014. This is in place to ensure that there are enough providers available to cover periods of high demand and low renewable generation.
“As coal units decommission other units will be able to access the capacity market agreements through a competitive auction.”
Magill says 30% of the UK’s energy came from solar, wind and water in 2020 in a record-breaking year, and that energy storage and demand flexibility will have to play an ever increasing role in balancing supply and demand.
“Storage already plays a critical role in supporting the energy system, from fast acting batteries to control the frequency through our two premium services of EFR and Dynamic Containment, through to longer-term storage, which is expected to take advantage of the low prices during high renewable periods to store energy and release it at times when the prices are higher.”
Henderson says traditional sources of electricity will still be needed for the short to medium term as renewable technologies develop.
“In the medium to long term, that development needs to deliver an increase in the country’s energy storage capacity through various technologies — so that we have energy on demand, from those key green sources for those times when there is no sun and wind,” he says.