Wild is the wind

The resource that could power the world.

A wind turbine blade at the Siemens Gamesa factory in Hull.  Source: The Guardian

A fascinating article from the Guardian:

The wind rips along the Humber estuary in Hull. It’s the kind that presses your coat to your back and pushes you on to your toes. “A bit too windy,” shouts Andy Sykes, before his words are swept away. He is the head of operational excellence at the Siemens Gamesa factory, which supplies blades – the bits that turn – to windfarms in the North Sea. At 75 metres long, they are hard to manoeuvre when it’s gusting.

Inside the vast factory hall, the blades lie in various states of undress. Several hundred layers of fibreglass and balsa wood are being tucked into giant moulds by hand. There are “naked” blades that require paint and whose bodies have the patina of polished tortoiseshell. Look through the hollow blades from the broadest part, and a pale green path, the tinge of fibreglass, snakes down the long tunnel, tapering to a small burst of daylight at its tip.

“Alice in Wonderland,” Sykes says. “That’s how I feel. That’s the emotion coming through. It’s 75 metres long. We know that. But stood here the perspective is just fantastic. It’s my favourite view.” Down this strange green rabbithole is a glimpse of a greener future, the possibility of a world powered by wind.

This is not as fanciful a vision as it once seemed. In the UK, the wind energy industry is celebrating. Last month, the cost of renewable energy dropped dramatically to undercut by almost half the government’s projections for 2025. At £57.50 (US$73) per megawatt-hour (MWh)[for offshore wind], it is far cheaper than the state-backed price of £92.50 awarded in 2016 to Hinkley nuclear power station. The speed of wind’s progress is extreme and inarguable.

The wind energy sector is certainly booming. Across the river from the Siemens Gamesa factory in Hull, in this long windy corridor of development on the east coast of the windiest country in Europe, there’s the Dong Energy hub, the screens of its operation room flickering with the data of wind captured by blades turning in the North Sea. Next month, the company will change its name – short for Danish Oil and Natural Gas – to Ørsted, after the celebrated Danish scientist who discovered that electric currents create magnetic fields, to reflect its near complete shift from black energy to green.

Dong was among the companies that achieved the landmark price of £57.50, and Emma Toulson, who works in their Grimsby office, explains how they did it.

Since the government ruled out new onshore windfarms in England – a promise in its 2015 manifesto – energy companies have been forced offshore, making the UK the world’s offshore leader. Allowed to develop beyond the vision of land-dwellers who see windfarms as a blot on the countryside, the turbines have grown steadily larger, as have the farms to which they belong. Dong’s Hornsea Project Two will span 480 sq km, and Toulson’s PowerPoint outlines a large jagged blue diamond for Project Three and an even larger blue rocket shape for Four.

Toulson has a slide that shows one very clear reason for the falling cost of wind energy. Over time, the diameter of the blades have enlarged. A turbine commissioned in 2002 swept 80 metres; in 2005, that figure rose to 90 metres; in 2011, it was 120 metres. By 2020, it will be 180 metres.

Of course, the supply chain has improved, and there have been engineering refinements. But put baldly, wind energy costs less, and will go on costing less, because the turbines are growing taller and the blades longer. The manufacturers of these machines are in a race to produce the largest.

And yet despite the size of its gargantuan machines, the offshore wind industry is still in its infancy. Wind turbines may look alike, but as Garrad points out, “we are a long way from a design consensus”. There are fixed turbines and floating turbines, which can access deeper seas, turbines with gears and turbines without. The sight of three blades harmoniously turning has become commonplace. But there is no reason why offshore turbines should look like this. They could operate with a single blade (ruled out on land because one blade, whirring faster, is noisy), or with two blades (ruled out on land because an optical illusion makes them appear to pause as they pass the tower, flummoxing passersby). Offshore, there would be only the gulls to offend, and the people who will live, in four-weekly shifts, on the new accommodation vessels that are being deployed to manage the farms’ growing distance from shore.

Ken Caldeira is one of the two Stanford climate scientists behind the idea of a North Atlantic windfarm the size of India. To understand the significance of his discovery, he says, it is important to know that when wind turbines are arrayed in rows, the extraction of wind by the first row reduces the amount of wind available for the second row, and so on. Row by row, the wind’s potential diminishes.

To counter this effect, turbines need to extract energy from the wind that’s above them. What Caldeira found was that that is exactly what can happen in parts of the North Atlantic, where heat “pours out of the ocean”, causing greater “cyclonic activity”. But could a farm the size of India really be built in open ocean? “You wouldn’t want to,” he says. Better to have many very large ones (China currently has the largest). A wind power station that size “would be a climate change in itself”. For one thing, “pulling that much energy out of the sky shifts the direction of wind”.

“The total amount of power in winds globally is something like 50 times bigger than the total amount of power used by human civilisation,” Caldeira reckons. “If we were to power civilisation by winds, we would need to capture about 2% of winds today,” he says

[Read more here]

Elon Musk has said that the whole USA could be powered by a 100 by 100 mile square somewhere in the south west of the country, and the battery storage to "firm" that would require just 1 square mile.  The USA covers 3.8 million square miles.  In other words,  only 0.26% of the US's land area would be used for solar panels.  And that doesn't even count rooftops!

Area needed to power the whole US by solar.  Source: Inverse

The moral is clear: we have more than enough wind and solar resources to run our economies.  Because solar requires more storage than wind and because wind and solar are complementary (for example, the wind is stronger in winter when the sun is weaker), a blended grid with both wind and solar is the cheapest option.  To that we'll add some battery storage, some pumped hydro, and some concentrated solar power (CSP), and perhaps, in high latitudes, power-to-gas.