Surprise, surprise: Wind turbines do lower carbon emissions

Counter-intuitive thinking is counter-intuitive for a reason.

Climate sceptics have long made the counter-intuitive claim that wind turbines don't actually reduce carbon emissions, but data analysed by the Guardian's environment blog suggests that as well as being counter-intuitive, it's just plain false.

The claim the Guardian's Chris Goodall and Mark Lynas investigated relies on the fact that wind power fluctuates with the weather. As a result, when the windspeed drops, gas power stations have to be spun up to provide electricity instead. It has to be gas, because other low-carbon sources of energy either have the same fluctuations as wind, or, like nuclear power, essentially can't be turned off.

The sceptics argue that the need to rapidly turn on the gas generators means that a type of power station known as a "gas-fired open cycle turbine" (OCGT) has to be used. Their key point is that these turbines, which are capable of being put into use extremely quickly, are less efficient than another type of gas generator, a "combined cycle gas turbine" (CCGT). The need to pick up the slack left by wind power, they say, means that so many of these inefficient turbines are used that carbon emissions actually go up compared to the scenario where all the electricity is generated with the more efficient CCGT type.

The Guardian's blog contains a lot of stats taken straight from the National Grid, all of which confirm the intuitive beliefs: wind power replaces fossil fuels. But for the specific claim that it still results in higher carbon emissions, the operative paragraph is the following:

Their arguments are not borne out by current statistics, however. If the sceptics were right, the recent windy conditions would have seen considerable use of less-efficient OCGT as wind input to the grid ramped up and down. In actual fact, during the entire June-September period, OCGTs and equally dirty oil-fired stations produced less than one hundredth of one percent of all UK electricity. In total they operated for a grand total of just nine half hour periods in the first 19 days of the month – and these periods had nothing to do with changing windspeeds.

In other words, the mechanism the sceptics suggested might be at work isn't. The authors go into greater detail about why that is, as well. In essence, it comes down to the fact that wind power isn't actually all that unpredictable. It comes and goes, but we usually have a good few hours warning about when it's going to die down; and it's spread throughout the country, allowing even more flattening of the peaks and troughs in supply.

The bigger reason for having to suddenly spin up big generators isn't sudden drops in supply, but sudden peaks in demand. Take, for example, a World Cup match, where England have made it through to sudden death penalties. The National Grid know there will be a spike in power consumption the minute the match ends, as people get up to put the kettle on – but they can't know when that spike will be until mere seconds before it actually happens. That sort of load will always be problematic to supply with renewables – but it's not much less problematic to supply with fossil fuel either.

Wind turbines. Photograph: Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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PMQs review: Theresa May shows how her confidence has grown

After her Brexit speech, the PM declared of Jeremy Corbyn: "I've got a plan - he doesn't have a clue". 

The woman derided as “Theresa Maybe” believes she has neutralised that charge. Following her Brexit speech, Theresa May cut a far more confident figure at today's PMQs. Jeremy Corbyn inevitably devoted all six of his questions to Europe but failed to land a definitive blow.

He began by denouncing May for “sidelining parliament” at the very moment the UK was supposedly reclaiming sovereignty (though he yesterday praised her for guaranteeing MPs would get a vote). “It’s not so much the Iron Lady as the irony lady,” he quipped. But May, who has sometimes faltered against Corbyn, had a ready retort. The Labour leader, she noted, had denounced the government for planning to leave the single market while simultaneously seeking “access” to it. Yet “access”, she went on, was precisely what Corbyn had demanded (seemingly having confused it with full membership). "I've got a plan - he doesn't have a clue,” she declared.

When Corbyn recalled May’s economic warnings during the referendum (“Does she now disagree with herself?”), the PM was able to reply: “I said if we voted to leave the EU the sky would not fall in and look at what has happened to our economic situation since we voted to leave the EU”.

Corbyn’s subsequent question on whether May would pay for single market access was less wounding than it might have been because she has consistently refused to rule out budget contributions (though yesterday emphasised that the days of “vast” payments were over).

When the Labour leader ended by rightly hailing the contribution immigrants made to public services (“The real pressure on public services comes from a government that slashed billions”), May took full opportunity of the chance to have the last word, launching a full-frontal attack on his leadership and a defence of hers. “There is indeed a difference - when I look at the issue of Brexit or any other issues like the NHS or social care, I consider the issue, I set out my plan and I stick to it. It's called leadership, he should try it some time.”

For May, life will soon get harder. Once Article 50 is triggered, it is the EU 27, not the UK, that will take back control (the withdrawal agreement must be approved by at least 72 per cent of member states). With MPs now guaranteed a vote on the final outcome, parliament will also reassert itself. But for now, May can reflect with satisfaction on her strengthened position.

George Eaton is political editor of the New Statesman.