News that the Ferrybridge and Longannet power stations are closing early has the industry searching for alternative measures

Nick Cullen

The new secretary of state at DECC, Amber Rudd, has put ‘keeping the lights on’ amongst her top priorities, which also includes securing a deal at the next climate conference in Paris.

News that the Ferrybridge power station (2GW) is to close seven years ahead of plan must have come as a blow to the DECC, particularly as this follows fast on the heels of the announcement that Longannet power station (2.4GW) in Scotland is also destined to close early. Both are big coal powered stations, accounting for 6% of UK capacity between them.

No doubt alarm bells are ringing in the department, particularly as the winter of 2015/16 is forecast to be particularly vulnerable to blackouts. According to Ofgem, the de-rated capacity margin before the announcement was less than 4%. If demand creeps up due to economic growth and we experience a cold winter, we may well be in for some dark nights. Bearing in mind that even gas-fired power stations take years to build, replacement capacity is not likely.

In many ways, part of the problem is the growth of renewables at the expense of the conventional thermal power plant. The intermittent nature of renewables means that their ‘availability’ is assumed to be 25% compared with thermal plant which is in excess of 80%.

The industry is working on ways of increasing the availability. In particular there are efforts to integrate storage technology close to generation so as to provide a continuous output from the generator, as well as attempts to disperse the storage across the country. A couple of weeks ago Tesla announced a major investment in this dispersed storage, joining a UK company in the market.

Installing small capacity storage across a ‘virtual’ network enables a variety of individual energy strategies to be employed for the benefit of the user. But if controlled as a single entity they can also support the network as a whole.  

By integrating storage at the end user’s premises, a range of peak lopping storage strategies can be enabled. A peak lopping strategy uses electricity to charge batteries during off-peak hours and uses that stored energy to reduce peak demand.

The system can go a step further and only charge from the grid when there is renewable energy available. This would directly increase the ‘availability’ of the renewable power device, as the stored electricity could discharge when output from the renewables was not generating. Likewise the storage can work directly with building integrated renewables to store excess electricity generated by the building.

When acting as a single combined virtual power source, the pressure on the grid at the crucial maximum demand period would be reduced.

I have recently had such a battery installed, the Moixa’s Maslow system. It is part of a DECC trial of some 250 installations around the country. The system can pool the combined storage capacity of the 250 installations and offer the 0.5MW to the grid at peak times at premium rates.

This is obviously a small contribution, but if offered across a portfolio of millions, the system could make a difference by feeding gigawatts of power into the network at peak times, offsetting the loss of Ferrybridge and Longannet. If installed with a smart meter this could not only transform our electricity network but provide some much needed resilience and capacity to the system while making the most of the investment in renewables.

Nick Cullen is a partner at Hoare Lea