OREANDA-NEWS. Scotland's energy minister Fergus Ewing has called for an urgent change in UK energy policy to support plans for new build generation capacity and requested reassurances over the country's energy security.

The UK's electricity capacity margins are "worryingly low" and the UK government's energy policies risk further exacerbating the situation, Ewing said in a letter to UK counterpart Amber Rudd.

The letter comes after UK transmission system operator (TSO) National Grid issued a notice of insufficient system margin (Nism) last week — the first since 2012 — owing to extremely low levels of wind power generation and following a series of unplanned plant outages.

"National Grid issuing an urgent request for more electricity shows that it is becoming even harder pressed to keep the lights on this winter and highlights the complacency of the UK government's energy policy" Ewing said.

The Scottish government has repeatedly called for changes to be made to UK energy policy over the past year, with the UK's transmission charging regime — which imposes higher costs on Scottish generators owing to their distance from the UK's most densely populated residential areas in southeast England — cited by UK utility Scottish Power as a key factor in its decision to close its 2.4GW Longannet coal-fired plant at the end of March next year. And plans for the development of new renewable energy capacity in Scotland have been hit by subsidy cuts for both new solar and onshore wind farms.

"The situation of narrowing GB capacity margins will only be exacerbated when Longannet closes prematurely next year due to unfair transmission charges. Longannet could have played an important role for several years to come as we continue our transition towards cleaner forms of generation" Ewing said.

A change in energy policy is required to allow new generation capacity to be built faster. The UK's future generation mix should incorporate a combination of renewable energy capacity with storage facilities, as well as thermal capacity with carbon capture and storage technology installed, Ewing said.

National Grid's market Nism was later cancelled following an adequate response from the market for more generation and after 40MW of demand side balancing reserve capacity (DSBR) was dispatched. The TSO can use its DSBR and supplemental balancing reserve if supply margins drop to low levels this winter, and Amber Rudd said she is confident that the government has supplied National Grid with powers to ensure the UK's security of power supply.

"National Grid has the right tools in place to manage the system this winter and we will ensure that they continue to do so in future" Rudd said. "In the longer term we are investing in infrastructure and low-carbon energy supplies, such as nuclear and shale gas, to improve energy security for future generations".