MORE than a dozen of the top onshore wind generators in Britain – all of which are in Scotland – were asked to turn down their production for the National Grid in August, a study has found.

Cornwall Insights also highlighted that wind was the first, most-utilised renewable technology to be asked to turn down its balancing mechanism (BM).

It said management of wind resources is a critical tool in dealing with system constraints, issues of supply and demand imbalance and inertia, which determines how quickly frequency changes on the network.

A total of 14 Scottish onshore generators were asked to cut back production in August.

James Brabben, wholesale manager at Cornwall Insight, said the high proportion of onshore wind in Scotland and constraints on the network were to blame for the cut.

“Effectively when there is high wind output in Scotland, especially northern Scotland, restrictions on the physical network make it difficult to transport power to areas with more demand which are predominantly located further south,” said Brabben. “National Grid will often constrain wind production to avoid system issues and provide a constraint payment. This issue has been exacerbated recently with problems surrounding the newly commissioned High-Voltage Direct Current HVDC Western Link.

“Instead of reducing constraint payments, recently these payments have hit record monthly highs this year and topped £8.5 million alone in August.”

Brabben said the constraints were reflected in BM actions. Cornwall Insight research showed 91% of those taken in August were what is known as “SO-flagged”, and added: “This is where balancing actions are flagged as system issues – such as constraints – rather than energy issues.

“The high volume of flagged actions clearly shows how physical system constraints are impacting the BM, leading to large volumes of wind generation each month being curtailed.

“While the development of further onshore wind in Scotland is crucial for further growth in renewable electricity, interactions with the physical network will create challenges and likely lead to greater levels of activity in the BM unless further network reinforcements or solutions are found.”