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Hot air about wind farms

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A paper by Liming Zhou and friends appeared in Nature Climate Change on April 29, 2012:

The wind industry in the United States has experienced a remarkably rapid expansion of capacity in recent years and this fast growth is expected to continue in the future. While converting wind’s kinetic energy into electricity, wind turbines modify surface–atmosphere exchanges and the transfer of energy, momentum, mass and moisture within the atmosphere. These changes, if spatially large enough, may have noticeable impacts on local to regional weather and climate. Here we present observational evidence for such impacts based on analyses of satellite data for the period of 2003–2011 over a region in west-central Texas, where four of the world’s largest wind farms are located. Our results show a significant warming trend of up to 0.72 °C per decade, particularly at night-time, over wind farms relative to nearby non-wind-farm regions. We attribute this warming primarily to wind farms as its spatial pattern and magnitude couples very well with the geographic distribution of wind turbines.

The effect is clearly local and due to mixing of different layers of air over the same point as the ground. As a result, at the ground level the temperature rises by less than a tenth of a degree per year. No extra heat is added to the atmosphere, so this does not contribute to global climate change. The overall effect of this mixing is still unclear.

WSJ seemed to have the most balanced article among the hundreds now out:

Large wind farms slightly increase temperatures near the ground as the turbines’ rotor blades pull down warm air, according to researchers who analyzed nine years of satellite readings around four of the world’s biggest wind farms.

The study showed for the first time that wind farms of a certain scale, while producing clean, renewable energy, do have some long-term effect on the immediate environment.

Using sensors aboard a NASA satellite, researchers at the University at Albany-State University of New York, and the University of Illinois systematically tracked a cluster of wind farms in central Texas as the installations grew from a few dozen turbines in 2003 to more than 2,350 by 2011.

Despite long-standing interest in the environmental impacts of such large-scale alternative-energy installations, this is the first time anyone has measured how wind turbines can alter local temperatures over the long term, the scientists said. So far, the scientists don’t know if these higher temperatures affect local rainfall or other weather patterns.

Normally, the nighttime air is a layer cake of cool and warm air, caused as hot air rises and cold air sinks, with the coolest air closest to the ground. As the giant rotor blades churn the air, they draw the warmer nighttime air down to the surface.

“If you have a wind turbine spinning, there is a lot of turbulence in the wake just like a boat in the water,” said Mr. Roy. “The turbine pulls warm air from aloft and pulls it down and takes cooler air underneath and pushes it up. That creates a warming effect near the surface.”

Although the researchers detected some daytime warming because of the wind farms, the temperature changes were highest in the predawn hours, when the air normally is still and not so turbulent, the researchers said.

Speculation took over everyone else. The UK Telegraph couldn’t help spicing up an otherwise responsible article with a dash of disaster:

Usually at night the air closer to the ground becomes colder when the sun goes down and the earth cools.

But on huge wind farms the motion of the turbines mixes the air higher in the atmosphere that is warmer, pushing up the overall temperature.

Satellite data over a large area in Texas, that is now covered by four of the world’s largest wind farms, found that over a decade the local temperature went up by almost 1C as more turbines are built.

This could have long term effects on wildlife living in the immediate areas of larger wind farms.

It could also affect regional weather patterns as warmer areas affect the formation of cloud and even wind speeds.

The Guardian was super careful; preferring to quote experts:

“The result looks pretty solid to me,” said Steven Sherwood at the climate change research centre at the University of New South Wales, Australia. “The same strategy is commonly used by fruit growers, who fly helicopters over the orchards rather than erect windmills, to combat early morning frosts.”

“Overall, the warming effect reported in our study is local and is small compared to the strong year-to-year changes” that result from natural variation, said Zhou. The study is published in the journal Nature Climate Change.

He told the Guardian that his results could not be used as an justification for blocking new windfarms. “The warming might have positive effects,” he said. “Furthermore, this study is focused only on one region and for only 9 years. Much more work is needed before we can draw any conclusion.”


Written by Arhopala Bazaloides

April 30, 2012 at 6:25 pm

The green energy market

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Reviewing the book “The Politics of Climate Change and the Global Crisis: Mortgaging Our Future” by Praful Bidwai in the Deccan Chronicle, Vandana Shiva writes about what makes it unique:

Firstly, it combines rigorous details of the climate crisis and international negotiations with robust arguments for climate justice and ecological democracy (which I call Earth Democracy). Secondly, it is the only book about India’s climate policy from a people’s perspective. As he writes “The climate crisis confronts India with many questions and some tough choices. India is emerging as a major power despite the persistence of mass deprivation and poverty at home. Yet, there is no genuine domestic debate on law and to what ends India should deploy its growing power. How can it be used to make the world better — less unequal and unjust from being conflict prone and violent? How can India combine the long overdue domestic task of fighting poverty with promoting global justice? In what ways can India contribute to the climate stabilisation and developmental equity agendas?”

India can have a carbon-free, nuclear-free future based on renewables. Renewable energy can provide more than 3,000 times the world’s current energy needs. As Bidwai concludes in the chapter titled, “The renewable revolutions is here”, “Policymakers everywhere need to develop moral and political clarity about the world’s renewable energy-based future and its inseparable links both with equity and combating climate change”.

Are these the pipe dreams of idealists? Apparently not, if you go by this hard-nosed report from the Guardian:

India’s transformation into a cleantech powerhouse moved up a gear in 2011 when it racked up investments of $10.3bn in the sector, a growth rate of 52 per cent year on year that dwarfed the rest of the world’s significant economies.

Solar investments led the growth with a seven-fold increase in funding, from $0.6bn in 2010 to $4.2bn in 2011, just below the $4.6bn invested in wind during the year, according to figures released yesterday by analysts Bloomberg New Energy Finance (BNEF).

A record 2,827MW of wind energy capacity was added in 2011, which kept India third behind China and the US in terms of new installations. BNEF said a further 2,500MW to 3,200MW could be added in 2012.

Grid-connected solar also saw a substantial increase, up from 18MW in 2010 to an estimated 277MW by the end of 2011, while another 500MW to 750MW of solar projects could be added in the coming year.

But India still has significant scope for growth as it only accounts for four per cent of global investment in clean energy.

Nevertheless, this huge growth in a year of a slowdown may indicate that green energy is beginning to become cost-competitive.

Germany, over the years has discovered a way to make green energy economically acceptable. The UK climate change minister, Greg Barker, writes in the Guardian:

There’s no denying that Germany has been a real pioneer in building a competitive low-carbon economy. Its renewables industry supports 340,000 jobs and replaces €5bn (£4.3bn) worth of energy imports per annum.

[T]his renewables powerhouse .. has learnt [lessons] from its well-established feed-in tariffs (Fit) scheme. … The Fit scheme rewards people financially to generate and export electricity they produce from renewable sources like solar panels and wind turbines. … [T]he solar industry has seen a massive boom from Fits here.

We need a mix of low-carbon energy to protect ourselves from volatile fossil fuel markets and disruption to supplies from unrest abroad. There is no choice but to have a sustainable energy source that we can guarantee will be there for us when we switch on the lights.

One of the most overlooked and underrated weapons in our energy security armour is energy efficiency. Reducing energy demand will be crucial to cutting bills and managing supplies. In short, it’s the energy we don’t use which will be the most reliable. This is why the coalition is introducing the green deal.

British, and German, policy is rooted in profitability. So it is worth understanding why and how these governments are moving towards sustainable energy.

Written by Arhopala Bazaloides

February 5, 2012 at 4:41 am

Green power: technology vs policy

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From Der Speigel:

Germany’s renewable energy companies are a tremendous success story. Roughly 15 percent of the country’s electricity comes from solar, wind or biomass facilities, almost 250,000 jobs have been created and the net worth of the business is €35 billion per year.

But there’s a catch: The climate hasn’t in fact profited from these developments. As astonishing as it may sound, the new wind turbines and solar cells haven’t prohibited the emission of even a single gram of CO2.

Even more surprising, the European Union’s own climate change policies, touted as the most progressive in the world, are to blame. The EU-wide emissions trading system determines the total amount of CO2 that can be emitted by power companies and industries. And this amount doesn’t change — no matter how many wind turbines are erected.

Is face value undergoing inflation? The whole article is definitely worth reading.

Written by Arhopala Bazaloides

February 10, 2009 at 6:20 pm

Samso: remember the name

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From the Observer comes this “be the change” sort of story:

But Samso has recently undergone a remarkable transformation, one that has given it an unexpected global importance and international technological standing. Although members of a tightly knit, deeply conservative community, Samsingers – with Jorgen in the vanguard – have launched a renewable-energy revolution on this windswept scrap of Scandinavia. Solar, biomass, wind and wood-chip power generators have sprouted up across the island, while traditional fossil-fuel plants have been closed and dismantled. Nor was it hard to bring about these changes. ‘For me, it has been a piece of cake,’ says Jorgen. Nevertheless, the consequences have been dramatic.

Ten years ago, islanders drew nearly all their energy from oil and petrol brought in by tankers and from coal-powered electricity transmitted to the island through a mainland cable link. Today that traffic in energy has been reversed. Samsingers now export millions of kilowatt hours of electricity from renewable energy sources to the rest of Denmark. In doing so, islanders have cut their carbon footprint by a staggering 140 per cent. And what Samso can do today, the rest of the world can achieve in the near future, it is claimed.

Read more about it via google.

Written by Arhopala Bazaloides

January 26, 2009 at 5:53 pm

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