National Wind Watch: Wind Energy News » Wind farm expansion will require fridges to be switched off at times of peak demand

Household fridges and freezers will need to be automatically switched off at times when Britain’s electricity demand is high, in order to keep the lights on as Britain becomes more reliant on wind energy, experts say.

The current electricity grid will struggle to cope with the number of wind farms expected to be built by the early 2020s because the power they produce is so intermittent, according to a report from the Royal Academy of Engineering.

A radical overhaul of the way the electricity system is managed – including a “smart grid” that can control household appliances to reduce demand when power supply is inadequate – will be needed, it finds.

Britain will also need to build more power import and export cables to the continent to help manage variable wind power output, and develop storage technologies to keep surplus power for times when there is a shortfall.

The measures will be necessary to avert blackouts under a vast expansion of wind power – unless Britain instead builds an expensive new fleet of reliable power stations to be fired up as backup when the wind doesn’t blow, it found.

Professor Roger Kemp of Lancaster University, said: “If there is a sudden peak in electricity demand the smart freezer would say, ‘OK I’m going to switch off for half an hour until that peak is over’.”

Consumers could negotiate cheaper energy tariffs for consenting to this and would not be affected by the temporary switch-off, he said.

“If you didn’t have a smart grid and smart control of domestic equipment, you would probably find prices would have to go up more because the power system people would have to build more power stations as back-up.”

The report say that “the ability to manage demand to reflect the output from wind will be vital to the successful integration of larger amounts of wind capacity”.

However, it casts doubt on the viability of this solution, warning: “There is much uncertainty on how effective it will be and at what cost.”

The report finds that the current grid can cope with “up to a 20pc contribution from wind power without the need for significant upgrades to the system and using existing balancing mechanisms”.

Beyond that threshold – expected to be crossed by the early 2020s – “managing the system will become increasingly difficult”, it warns.

The inherently variable nature of wind power will present problems when there is a mismatch between wind output and consumer demand – either too much wind or not enough.

“During periods of high demand, wind still often produces very low levels of output,” the report finds.

“At low levels of penetration [wind energy deployment], this should not be a major issue and, indeed, up to now security has not been compromised despite periods of virtually no output from wind and maximum demands. However, as levels of penetration increase, the situation can be expected to change adversely.”

If wind power continues to expand beyond 2020, days of negligible wind power could “present problems for security of supply”.

In the reverse scenario, where wind output is high but demand is low, wind farm owners could increasingly have to be paid to switch their turbines off – an “inefficient and costly” solution if it becomes more common.