EmailRenewable energy, such as wind and solar power, is frequently criticised for being “unreliable”. But the major fire at RWE’s Didcot gas-fired power station on Sunday evening shows that traditional energy generation is also intermittent. Moreover, accidents at coal, gas and nuclear plants frequently involve much larger amounts of electricity dropping off the grid and at much shorter notice.
The Didcot station was running at full capacity on Sunday evening, RWE told me. So the cooling tower fire, which forced unit 5 to close, led to the instantaneous loss of 700MW of electricity just after 8pm. That is about half-a-million-homes-worth of power that the National Grid had to find with zero seconds’ notice.
It pulled off this balancing act using a safety net, called the regulating reserve, that it is one of a number of back-ups always on standby to ensure the UK’s electricity supply remains stable. The regulating reserve is a mix of electricity, such as pumped storage and gas power, kept in reserve to compensate for any sudden drop outs.
Big power stations shutting at short notice is more common than you might think.
The Didcot fire is at least the third at a UK fossil fuel-fired power station in 2014, according to Reuters. In February, fire permanently closed E.ON’s 370MW unit at Ironbridge, while in July, two units at SSE’s 1,000MW Ferrybridge coal plant in West Yorkshire were shut after a fire.
Neither is nuclear immune from shutdowns, with EDF Energy taking four of its nuclear reactors offline in August after a crack was found in a boiler. Combined with Didcot B, these unplanned outages alone have removed 7% percent of total electricity generation capacity.
The first lesson to draw from the Didcot fire relates to energy security. Due to their size, problems at centralised power plants pose a greater risk to keeping the lights on than the loss of, say, one turbine in a wind farm, or a few solar panels in an array. Power station drop-outs can occur suddenly and for unexpected reasons, like a plague of jellyfish or seaweed, both of which have knocked out nuclear power stations recently. In contrast, wind can be accurately forecast a day or two ahead and the sun rises and sets like clockwork.
The risk posed by big plants falling off the grid will rise further if EDF build their 3.2GW nuclear plant at Hinkley Point in Somerset. Such is its size - a “behemoth” according to Owen Paterson - that National Grid is having to ramp up its back-up measures to cope. In a stunning example of perverse logic, the £160m-a-year cost of this bigger safety net is being spread across all energy suppliers, including renewables, because “increasing costs on larger users could delay the commissioning of large nuclear plants”.
The second lesson to draw from the Didcot fire is that the intermittency of some renewables is simply not a problem. On Sunday, the same day the Didcot station crashed offline, wind power provided its greatest ever share of UK electricity: 24%. And the lights stayed on.
In April, a Royal Academy of Engineering report concluded wind capacity could more than double from today’s 11GW by 2020 without any changes to how the energy system is balanced. The grid can cope.
It is ironic that Sunday was also the day that the Conservative party’s war on renewable energy opened a new front, with environment secretary Liz Truss changing farm subsidy rules to undermine solar farms. This is despite solar energy being a “promising technology” whose price is “falling rapidly” – and that’s Tory climate sceptic Tim Montgomerie talking.
Renewable energy come out as most popular in every opinion poll, with solar often getting more than 90% approval. It boosts energy security by being both decentralised and not relying on imported fossil fuels. Onshore wind is the cheapest clean energy available, but communities secretary Eric Pickles continues his crusade against it.
As the flames of Didcot burned, Truss and Pickles fiddled in order to foil renewable energy and appease the minority of the public who oppose it.
