Skip to content

Reassessing wind power

Energy security has quite rightly become a high-profile issue, with regular newspaper articles and letters to editors. Talk of power cuts or brownouts is common and, despite the current unusually mild weather in many places, these could become a reality if we get cold spells this winter. The chaotic nature of weather systems makes it impossible to predict what will happen, and the UK Met Office’s shiny new supercomputer (Met Office to build £97m supercomputer) won’t make any difference to that.

The government assures us that all will be well and that their energy policy is on the right track (see, for example I will keep Britain’s lights on, Ed Davey pledges). The energy secretary is quoted as saying “By increasing the use of non-imported energy sources, Europe will be less dependent on Russia” as part of his defence of his commitment to wind energy; “The Tory attack on wind farms will ultimately leave households paying bigger energy bills.”

Ignoring for now the wild and unsubstantiated assertion that wind energy will keep prices down in the longer term, he is quite careful not to make hard claims about wind increasing energy security. Instead he takes the tack of needing to rely on all available technologies to meet emissions cuts obligations under the Climate Change Act. “If you take a technology off the table, you are being reckless. You are taking risks, both on climate change and the consumer agenda. Onshore wind is the lowest cost renewable energy source, which is helping us meet our climate change targets under the Act.”

What he and many other politicians fail to acknowledge (at least in public) is the unreliability of wind energy. Really cold spells in winter are often associated with slow-moving areas of high pressure, giving us clear skies and, most importantly, no wind. Just when energy demand is highest, a significant part of the fleet standing idle. This is why there has to be on-demand back from conventional sources, mainly gas-fired stations, to keep the lights on. The latest plan to ensure there is enough capacity relies on the most expensive options possible, fleets of diesel generators (We could soon be paying billions for this wind back-up). Is this a sign of creeping panic from the government?

Hard data on this topic is not always easily available, particularly from the government and the renewables industry. This is why the Scientific Alliance was this week particularly pleased to publish, jointly with the Adam Smith Institute, a new report from Dr Capell Aris: Wind Power Reassessed: A review of the UK wind resource for electricity generation. This study analyses wind data collected at half-hourly intervals from 22 sites in the UK over a period of nine years, with further measurements from 21 sites in Northern Europe and Ireland. This allows the hour-by-hour output of a fleet of wind turbines of nominal 10GW capacity to be modelled.

The results are revealing, although not surprising to anyone who has taken time to look at actual outputs over different days. Power output is below 20% of nominal capacity for over 20 weeks of the year, and below 10% for nine weeks. The UK system produces 80% or more of its rated output for just 163 hours a year, or less than a week. Rapid swings in output mean that conventional plant must be left idling and ramped up at a moment’s notice.

For anyone who thinks that new wind turbine arrays will replace old coal and gas stations as they close down, the details of this study will be a rude awakening. New gas plants are being built to provide continuity of supply and, in simple terms, there must be conventional stations available to meet the entire capacity of the wind fleet to cope with calm days, particularly at times of high demand in winter.

Another argument often put forward in favour of wind energy is that the wind is always blowing somewhere, so having many turbines spread out over a wide area will to some extent smooth the output. This turns out not to be true; the ‘guaranteed’ output is only about 2% of the nominal rating, or 200MW instead of 10GW. Installing a wider grid, such as the proposed Europe-wide ‘super grid’ would make little difference.

The only way wind and solar power would be able to make more than a modest contribution to energy supplies and emissions reduction is when affordable energy storage is available on a massive scale, but this is still some way over the horizon.

We elect politicians to make wise decisions which keep us safe and secure. In pursuing the present policy on renewable energy with the currently available technology, they are not fulfilling their obligations. Woe betide the political party which presides over power cuts as a result of too little reliable generating capacity.