At the beginning of March the transmission operator opened the current round to bidders offering both power supply and demand reduction service, with a deadline of Friday 24 April.
But the deadline has now been extended to 7 May because interested parties say they need more time to make their submissions.
A spokesman for National Grid told Utility Week that there is not expected to be a delay in awarding the contracts by the end of next month, but that a decision was taken to extend the submission deadline following feedback from potential demand-response bidders that more time is needed.
The demand side balancing reserve (DSBR) is a relatively new measure taken by National Grid to balance strong winter demand against shrinking supply margins by contracting heavy energy users to reduce their demand on the grid at peak times.
“A lot of companies are still learning about this,” said the spokesman of the need for further preparation time.
So far National Grid has procured 242MW of DSBR contracts for the coming winter and intends to procure a further 1GW from demand and supply services.
A third tender round in the summer is possible, depending on the emerging picture of winter supply and demand.