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Profs: Massive use of wind turbines WON'T destroy the environment

Would destroy the economy, though

Windy professors in the States have produced research in which they say that massive use of wind power would not, as had been thought, damage the planet's atmosphere and cause undesirable climate changes. They also argue that it would be "practical" to obtain half the energy required by the human race using wind turbines.

Professors Mark Jacobson of Stanford and Cristina Archer of Delaware undertook their latest effort with the aim of rebutting research which came out last year (pdf) by German and American scientists, which said that the potential of global wind power is much less than wind-loving academics have previously assessed. That paper also, and perhaps more controversially, used atmospheric modelling to show that extraction of massive amounts of energy from the atmosphere by huge numbers of wind turbines (as would be required if the human race were to be powered to any large degree by renewables) would have similar negative climate consequences to doubling atmospheric CO2.

Jacobson and Archer set out to disprove this, and they say they have done so in a new paper to be published this week in the Proceedings of the National Academy of Sciences.

"Wind power is very safe from the climate point of view," says Professor Archer.

The new paper contends that maximum power output of 80 terawatts could be safely obtained by covering all the Earth's land masses and ocean near them with wind turbines 100m high, spread out individually. However the two profs seem to accept that this is perhaps a little bit ambitious, and move on to discuss "fixed wind power potential for more practical applications".

In this scenario, Jacobson and Archer suggest that 4 million wind towers, spread "worldwide in windy locations" to avoid harming the atmosphere, could safely produce a steady output of 7.5 terawatts, "more than enough to power half the world's power demand in 2030". This should be quite safe for the planet:

While wind power does alter the atmosphere when extracted at massive scales – decreasing wind speed at hub height and to a lesser extent at the surface, reducing the amount of water vapor and cooling the planet – the impacts are negligible at more practical scales of extraction, such as 7.5 TW.

We here on the Reg energy desk will have to leave Jacobson and Archer to battle it out with the German/American team at the Max Planck Institute regarding the matter of atmospheric damage from wind turbines vis-a-vis carbon emissions, and the actual amount of energy that there is to be had: we haven't got the intellectual ticket to get on the atmosphere-modelling bus.

But we do at least know what a Watt is - so let's take it as read that 4 million wind towers can produce 7.5 terawatts without messing up the weather. Is that actually enough to provide half of humanity's power?

Well, 7.5 terawatts is the same as 237 exajoules each year. Total world energy supply at the moment is 490 exajoules annually right now, so it would seem that Jacobson and Archer have cocked their sums up right out of the gate. Even if they're right, wind can only do 48 per cent of the job.

But given the past history of the two profs - of which, more below - it seems safe to say that they are actually assuming that humanity will be using a good deal less power by the year 2030. The Intergovernmental Panel on Climate Change, for instance, believes that humanity must and will slash global consumption down to 390-odd exajoules per year by mid-century.

The trouble with that scenario is that it starts from a situation today where the great bulk of the world's population is miserably poor and therefore using hardly any energy at all, which hardly seems fair - and the population is set to get bigger, too. If today's seven billion people each used only two-thirds of what a present-day European does we'd need supplies of 770 exajoules, not 390. In a more realistic scenario where the human population continues to climb, energy demand in the industrialised nations continues to rise instead of falling enormously and (hopefully) the world's poor start to get a taste of the good life, supplies in the zettajoule (1000 exajoule) range will be required within decades.

So, assuming Archer and Jacobson's figures are correct, wind power can't provide even a quarter of the power the human race might reasonably ask for. The two profs know all this background: the fact is that they don't believe people should be allowed even as much energy as two-thirds of the energy a modern European uses - far less the significantly larger amounts of juice consumed by today's Americans. It's something to bear in mind.

One also notes that wind towers yield about 25 per cent of their maximum rated power capacity over time, meaning that Jacobson and Archer must be talking about towers in the 8-megawatt capacity range if just 4 million of them are to yield 7.5 terawatts over time. No such towers are in service yet, so it might seem rather bold to make assumptions about them, but they are on the drawing boards. Rather optimistically, based on the costs of existing hardware, they might cost say $600k each when land based: which gives us a total cost of perhaps five or six trillion dollars just for the towers. Supporting infrastructure for landbased wind farms (roads etc) generally costs at least as much again on top of tower cost: say $12 trillion to start off with.

Figures so far have been based on landbased farms: offshore ones, which would presumably have to account for many if not most of the professors' proposed future installations (the new 8 MW turbines are intended mainly for offshore use by the wind biz right now) cost hugely more, so much so that the British government is finding that it must offer builders doubled incentive payments under the Renewables Obligation scheme to get offshore farms built, as compared to onshore. (These aren't subsidies from the taxpayer: the British RO scheme works by forcing up electricity prices invisibly and channelling the extra cash to renewables operators.)

Then there's the matter of hooking up the farms to the grid, which generally costs a hefty additional sum - in this scenario a very hefty one indeed as these towers are spread out rather than being clustered in "a few spots", in order to prevent them damaging the climate. This will also push up infrastructure costs hugely as more roads or other transport links must be built.

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