Expected low electricity demand in the UK over the upcoming Bank Holiday weekend because of Covid-19 could see several distributed-connected wind farm operators paid to cut output in order to manage the grid.
National Grid ESO said that small-scale renewable generators with over 2.4GW of capacity – including 1.5GW of wind power – have so far joined a new scheme called the Optional Downward Flexibility Management (ODFM) service.
ODFM is an opt-in service for small-scale renewable generators to receive payments from National Grid ESO if the network operator asks them to turn down or turn off their electricity generation.
National Grid ESO structuring and optimisation manager Amy Weltevreden said: “This capacity through the ODFM service is giving us additional options to manage the transmission network by reducing the amount of electricity supplied at the local network level to ensure there’s not too much power on the grid.”
Weltevreden said that although there are a lot of big wind farms connected to the network, much of the renewable electricity generated comes from these smaller units or what is called distributed or embedded generation.
She said: “Because they’re not connected directly to our transmission system, in the past we haven’t had as much ability to control the power they’re producing to balance the grid.
“If the wind is blowing and the sun is shining, that power they’re generating is being fed into the grid and having an effect on supply and demand.
“For example, in the middle of the day, when sunshine is strongest and solar generation peaks, we will see national demand being suppressed.
“While we don’t see the effects of this generation in real-time in the same way that we can with a big transmission-connected generator, we can forecast with a good degree of accuracy the power they’ll be producing given the likely weather conditions.
“And this is how we’re able to extract the most value from the ODFM service.
“If we’re anticipating the wind blowing at a given time when we’re also expecting low demand, we’re now able to instruct these smaller scale distributed generators to reduce output to help balance the system.
“As with any actions we take to balance the electricity system, they’re carried out in economic order, with cheaper actions taken first, to ensure we operate the system as efficiently as possible for consumers.”
Weltevreden said that on previous recent holiday weekends – Easter and VE Day – demand had been down by as much as 20% on last year in the UK.
National Grid ESO estimates that measures to balance the system this summer as a result of the Covid-19 impact on demand will cost about £500m more than the same period last year.
So-called Balancing Services Use of System charges were £333.2m (€372m) from May to August 2019, with the forecast for this year at £826.3m.
However, if National Grid ESO had not developed new approaches to combat Covid-19 impacts the cost would be higher at about £1.04bn, it said.