Storm Angus, which struck British shores last week, is suspected of having had a damaging impact on the UK’s biggest energy interconnector.
The news means less overall capacity for the country at a time when the capacity margin is already tight. Rob Lalor of energy consultancy EnAppSys told Power Engineering International the problem will have an inevitable impact on power prices.
The National Grid has confirmed that the Interconnexion France-Angleterre (IFA) interconnector with France is set to run at 50 per cent of its capacity until the end of February after investigations revealed four of its eight subsea cable were severed during the storm.
“We experienced a trip of the IFA interconnector on the morning of Sunday 20 November,” National Grid said in a statement. “After further investigation, the fault has been identified and we can confirm that four of IFA’s eight cables have been damaged. This will result in a reduction of IFA’s maximum capacity to 1000MW until the end of February 2017.
“Investigations are ongoing and teams on both sides of the channel are working to restore IFA to full availability. We will issue regular updates regarding progress.”
A spokesman said the company was investigating whether the damage was caused by a ship’s anchor dragging along the sea floor during Storm Angus.
National Grid predicted a capacity margin of 1.1 per cent during peak hours this winter, rising to 6.6 per cent once of the Supplemental Balancing Reserve. However, both these figures assumed 2GW of net imports from continental Europe, partly through the IFA link.
UK day-ahead power prices rose sharply on Monday, when the news broke, amid steady wind and higher power demand forecasts, sparking supply concerns.
Platts reports that at around midday Monday, wind power supplies stood at 1.5 GW, accounting for less than 4% of the UK energy mix, while no French imports were flowing through the IFA link, the grid data showed.
Gas-fired power generation reached 22 GW, representing more than half of the electricity supplies, while coal and nuclear power production was at 5.6 GW and 8.3 GW respectively.
Rob Lalor, energy analyst with EnAppSys consultancy told Power Engineering International, that this winter the French Interconnector has been seeing greater variety in terms of imports and exports between France and the UK.
Normally the interconnector imports power into the UK most of the time, but this winter levels of imports/exports have been far more varied due to capacity issues in both France and Britain.
"On the 15th, 17th and 18th of November this activity meant that the system was very short heading into the evening peak with what appeared to be very limited evening margin, between available supply and demand, only for the interconnector to turn from a ~2GW export to France for the day to a ~2GW import across the evening peak; ensuring that France was able to reduce its cost of baseload power across the day and that GB was able to manage a tricky evening demand peak," Lalor said.
"The interconnector has really been acting as a regulating valve, helping contain prices in both regions when there have been shortages and allowing UK generation to benefit from high prices in France and vice versa. The reduction in levels of capacity across this interconnector by 50 per cent will reduce the size of the regulating activity at a time when temporary shortages are becoming more common."
Lalor added that this winter has already seen some very higher power prices in both countries (with the UK seeing its first supplier go bust this winter period) and the main impact of this will be increased price volatility in both markets and an increased requirement for both nations to handle their own capacity issues domestically.
"Both countries expect to see tight margins during similar time periods, so the ability to meet peak periods shouldn't be adversely affected, but the ability of the interconnectors to regulate prices will be reduced."
"Where there would be exports to France this should benefit UK consumers and French generators at the expense of French consumers and UK generators, whilst where there would be imports from France this will benefit UK generators and French consumers at the expense of French generators and UK consumers, so with relatively even levels of imports and exports there should be no obvious net winner. Ultimately we all gain as a whole from these interconnectors and so the aggregate cost of power will be higher than would otherwise have been the case."