UK solar turn-off possible for first time this weekend: Limejump

London — This weekend could see UK solar plants instructed by system operator National Grid to turn off for the first time as low demand combines with high wind generation, Limejump's new Chief Operating Officer, Catherine Newman, told S&P Global Platts Thursday.

National Grid has said demand could sink below 14 GW on Sunday, May 24, and it was looking at options to deal with around 3.7 GW of excess supply.

One way is via its new 'footroom' product, known as Optional Downward Flexibility Management.

ODFM is for distributed generators who are not in the balancing market. The service requires a minimum 1 MW commitment and the ability to deliver for three consecutive hours after receiving a day-ahead instruction to reduce output.

Limejump manages a 1 GW-plus portfolio of flexible generation assets, including distributed wind and solar, batteries and gas peaker plants. It bids these assets into the UK's grid services markets and has been particularly active in recent weeks, Newman said.

"The drop in demand is a big concern," she said.

"We were in on the first footroom [ODFM] service two weeks ago ahead of the last bank holiday, and yesterday we offered a big chunk of wind and solar to National Grid for the coming weekend," Newman said.

With a low demand/high wind forecast, the weekend would likely see wind turned off and could see the first instructions for solar to turn off, she said.

"The system operator has never had access to turn off solar like this before. It is pulling all the levers it can. It has exercised the option to turn off capacity at Sizewell B; it will be selling everything it can on the interconnectors to Europe; and it will use all the pumped storage it can," Newman said.

The cost of paying distributed generators to turn off via ODFM needed careful consideration versus using the balancing mechanism itself, she said.

"Baseload power for Saturday traded at zero on Wednesday and since traded negative today. We have never seen that before. The least cost options have to be considered to limit costs to consumers," Newman said.

An extended period of low demand caused by the coronavirus could push balancing costs up to GBP826 million ($1.01 billion) in the four months to September this year, versus GBP333 million for the same period last year, National Grid said May 15.

Excluding the new services designed by National Grid to cope with the low demand, costs for the period could rise to over GBP1 billion, it said.

The coronavirus pandemic had put the market on a war-like footing, with the pace of change accelerating to meet emergency conditions, Newman said.

"COVID-19 has given people a renewed sense of purpose. Following the 2008 economic crash, carbon emissions increased 6% year on year. We do not want that again. We need more commitment to decarbonize, and we are seeing it in our conversations with lots of big companies who are asking us: How do I get to 100% renewable power?"