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Alternative Energies: wind power

by Jerome a Paris Sat May 13th, 2006 at 08:19:53 AM EST

This diary has been written at the request of DarkSyde, who has been putting up a series on alternative energies on the front page of DailyKos every Saturday, and is now posted prominently over there. But I imagine it is also of interest to you guys over here...

About 1 to 2 per cent of the energy coming from the sun is converted into wind energy. That is about 50 to 100 times more than the energy converted into biomass by all plants on earth.

That wind is generated by the fact that the air at the equator is warmer than at the poles. That hotter air rises and spreads out. Thanks to the rotation of the earth (the Coriolis effect) it tends not to go all the way to the pole and instead to move in largeish circles.

Local conditions, altitude, the flatness or ruggedness of the ground all have an impact on wind conditions at any given site. In general, wind near the ground suffers from turbulence, irregular patterns, and its energy is diseprsed by obstacles. as you go higher in altitude, it becomes more regular and steady, and is much easier to transform into usable energy.

The way to do it is to convert mechanical energy into electricity. The mechanical energy in wind is captured as mechanical energy by the blades of the wind turbine, which lead the rotor.

To convert that torque into electricity, a generator is needed, usually located in side the nacelle of the wind turbine. Electricity is then transformed into medium or high voltage current and sent into the grid.

:: ::

Today's turbines are typically 60-80 meters high, with blades 30 to 40 meters long:

Such turbines now have a capacity of 1.5 to 3 megawatts (MW), and typically generate 3-10 million kWh (or TWh) depending on the wind conditions. A big wind farm in the USA can include up to 100 turbines (150 MW) and generate, say, 500 TWh per year, enough to fulfill the needs of 45,000 families.

As a comparison, a typical coal-fired power plant will have a capacity of 600 MW and generate close to 5,000 TWh.

As the exemple above shows, wind farms generate fewer kWhs per MW, i.e. they have a lower availability factor, which is caused by the variability of the wind: it does not blow all the time, and it does not blow all the time at speeds enough to generate the maximum capacity of the turbine. Availability typically ranges from 20-30% for onshore windfarms to close to 50% for offshore projects or a few exceptional onshore locations. The good news is that wind tends to be available at the time of the day when we need it most, i.e. during the day and in the evening. But it's not available on demand.

:: ::

Let's go through the main advantages and potential drawbacks of windpower.


  • it requires no fuel. Once build, it produces endlessly (well, at least for the lifetime of the equipment, typically 20-25 years) renewable energy and requires no additional input. That lowers its cost of production, eliminates the price risk on such additional inputs and does away with the political risks associated with imports of valuable commodities, and the realpolitik that goes along with these;

  • it creates more jobs. Windpower is actually the energy source that creates the most jobs per kWh. 10 MW generate about 4 full time jobs, of which 2 will necessarily be located in the community that hosts the wind farm. Windfarm construction generates good industrial jobs in the mechanical, electrical equipement and financial industries (as all the investment needs to be done at the beginning, the financing costs are a vital part ofthe package). Today, the main manufacturers are based in Europe, but they are investing in facilities in the US a s demand here increases.

  • it is becoming quite price-competitive

    the graph above, from the Economist last year, does not fully reflect the nasty increases in gas and coal prices, and suggests that wind power is pretty much price competitive compared to alternatives. It still requires some minimal public support to be financed today, as banks are not quite ready yet to bet on $60+ oil over 20 years yet, but this may soon no longer be required;

  • it generates no carbon emissions. In today's world, not contributing to global warming is no longer an irrelevant argument. Wind power is the only power source (with nuclear, which has other issues to deal with) to not make that problem worse.

Against that, wind power has a number of real or perceived drawbacks.

:: ::

Potential drawbacks of wind power

  • it is intermittent. As discussed above, wind power cannot be produced on demand and is subject to the vagaries of wind speeds. This can be a handicap in some cases it would not do, for instance, as the sole power source for a hospital), and it excludes, for now, the hypothesis that wind power can contribute the majority of our power needs. But in practice, experience demonstrates that electricity networks can tolerate with almost no adjustment up to 10% of power coming from wind, and around 20% with some minor effort. We're still very far from these levels in most places (the USA in aggregate are still below 1%), so let's build capacity before we worry about that particular issue; In particular, the argument brandied around by some that building windfarms does not eliminate the need to build polluting plants, to be available as back up, is absolutely bunk.

  • it is ugly. This is the most contentious issue, as the numerous - and highly polemical - diaries about the offshore project on Cape Cod have shown. To a large extent, it is subjective, so there never will be a satisfactory reply to all. What can reasonably be said is that it is probably wise to avoid some sites of particular beauty. Studies in Scotland have shown that there was more acceptance of windfarms by their direct neighbors than by people a few miles away, which suggests that on the gorund work to educate and convince the locals prior to construction stand a good chance of allaying the legitimate fears of being invaded by massive towers.

  • it kills birds. This has been given some credence by the sad case of the Altamont Pass windfarms, where a combination of a poor location (in a migratory path), lattice structure (inciting birds to rest on the wind turbines) and small and fast turning blades created a nasty mix and led to too many raptors being killed. But with modern turbines (which rotate much more slowly), and provided that sensitive sites are avoided, the issue is really marginal. (See this diary for a specific discussion of bird issues, including the point of view of bird protection NGOs)

    Wind farms cause a negligible fraction (less than 0.01%) of all man-caused bird fatalities:

  • it is noisy. This may have been true of some of the older turbines, but it no longer the case. I have personally been around wind turbines and you can barely hear a hum.

  • it takes a lot of land. This is both true and untrue. It is true that a wind farm requires a lot of land, as big windfarms typically need to be spaced almost 500 meters from one another in order not to disturb their ability to capture wind energy. But the footprint of the wind turbines is actually very small, and the land around them can still be used. In rural settings, the impact on farmland is practically nil (the dirt road to get to each turbine, and a few yards around each) and farmers can still use it as before (and they get a really decent chunk of income from granting the land rights). In urban areas, it is obviously harder to build large scale windfarms, but small numbers can easily be built on or around industrial plants, port facilities, or along road or railways.

  • it costs taxpayers' money. It does, and it still needs that support (although, as explained above, less and less). Butthe big difference between wind and other power sources is that most subsidies for wind are explicit and visible, whereas subsidies for other energy sources are more discreet. Tax breaks for oil&gas companies, public insurance of nuclear power plants, and, the most important, the lack of payment for the environmental damage caused by the extraction, transport and burning of valuable (and yet dirty andf/or carbon rich) natural resources. and we won't even mention the cost of the Pentagon budget, a hefty chunk of which goes to protect energy imports. So subsidies for wind are actually fairly small, well identified, and correspond to a real public necessity. (And they make bankers like me more comfortable to finance wind farms...)

:: ::

Altogether, I think it can reasonably be said that the advantages far outweigh the disadvantages. There is not one single "magic bullet" solution to the current energy crisis, but wind is certainly one of the best options already available, and it needs to be deployed on a larger scale. The good news is that the industry is currently booming in the USA, after years of ups and downs linked to a chaotic renewal process for the main support mechanism, the PTC.

Energize America strongly supports the development of wind power (via a simple extension of the PTC) and expects that 200,000 MW can be built by 2020, creating more than 50,000 highly qualified jobs in the process.

:: ::

Some links

My diaries on the topic
Energy - some good news (for once)
Don Quixote meets Wall Street - financing wind farms
The future of power generation
Wind power: birds, landscapes and availability (I)
comment on PTC
Something to take your mind off indictments: Windfarm blogging
Wind power now CHEAPER for US retail consumers
USA to become world leader in wind power in 2005
2005 was a great year for wind power worldwide

On birds
American Bird Conservancy
Audubon Society

Professional organisations and sites
Danish wind power association (with a great intorduction to all parameters of wind power, starting here
American Wind Power Association
European Wind Power Association (with a great library of detailed studies)
Windfarm pictures (including construction) by Gunnar Britse

Great overview, thanks!

I'm still puzzled about why solar energy isn't being invested in more, since many of the drawbacks noted above would not be an issue. An there are lots of empty deserts and such. Is it a matter of lack of technology? Or what?

"Once in awhile we get shown the light, in the strangest of places, if we look at it right" - Hunter/Garcia

by whataboutbob on Sat May 13th, 2006 at 09:00:18 AM EST
Small systems are very popular in Finland for summer cottages etc. These cottages are only used, naturally, during the summer when in Finland there is sun all day and most of the 'night' ;-)

Out on the island in the Finnish archipelago, by choice we enjoy a primitive life for a few weeks with lavvies in the woods, wood fired saunas for washing, and outdoor cooking whenever possible etc. But we also have a solar panel for lighting at night, radios (weather reports), charging digital cameras, blogging and other not so primitive devices. We do have fridges, but they work better on gas cylinders which we bring in on the boat.

You can't be me, I'm taken

by Sven Triloqvist on Sat May 13th, 2006 at 09:32:08 AM EST
[ Parent ]
Current solar technology still makes the kWh 5-10 times more expensive than the existing producers (or than wind), so it is impractical to develop it on a grand scale yet.

But it needs to be supported precisely to get costs down, and for small scale, local, individual use. But that's someone else's job...

You'll be happy to know that a lot of money is being invested in the secotr right now.

In the long run, we're all dead. John Maynard Keynes

by Jerome a Paris (etg@eurotrib.com) on Sat May 13th, 2006 at 10:08:35 AM EST
[ Parent ]
Jerome, what percentage of the wind power available is converted to energy by a typical wind farm (on a given volume)?
by Laurent GUERBY on Sat May 13th, 2006 at 02:20:24 PM EST
[ Parent ]
Why don't we see more marine turbine projects ? Aren't they an answer to the perceived drawbacks of wind turbines ?


by balbuz on Sat May 13th, 2006 at 09:02:46 AM EST
I hope to report soon on developments with an innovative wave solution from Finland which is entering the industrial pilot stage. The company is a client of mine and I'm not at liberty at the moment to say any more than is on the website (see below)

WaveRoller is a giant wing which sits on the ocean floor near to shore, but seawards of the breaker line. It moves back and forth in powerful bottom currents. This enables the pumping of onshore turbines.

More about WaveRoller

You can't be me, I'm taken

by Sven Triloqvist on Sat May 13th, 2006 at 09:20:39 AM EST
[ Parent ]
Nice entry. I'm trying to get a job working on windmills (which may start with me moving to California doing what I do now first). Gotta get into that "net producer" category.

you are the media you consume.

by MillMan (millguy at gmail) on Sat May 13th, 2006 at 04:32:39 PM EST
the focus on energy on this blog is extremely heartening.

this elegant, well-formatted diary is a brilliant example of why blogs are becoming the medium-of-choice for me and countless digital others.


frankly blown away to see this ET concept taking wings so quickly and strongly; deepest thanks to all of you, for affirming that there is compassionate intelligence alive and well on the planet, and so far ahead of mine and most i meet, that i come here, spesso e volontieri, to humbly learn from masters of relevant data-capture and retransmission.

as donovan said so many years ago:

'might as well try and catch the wind'

singing is also 'catching the wind'!

and through increased oxidisation of the blood, turning it into different forms of energy....whatever we choose, really.

it occurs to me that living in windy places lowers chi, according to chinese medicine, so humans are not likely to be territorially jealous of winfarms for residential reasons.

unless they want to put up their own windmills, live off the grid, and wear scarves a lot.

which brings me to my next point: while being all in favour of windfarms, especially offshore ones, it's a pity that they are by default perpetuators of a relatively ancient, ugly, obsolete, and high-maintenance centralised energy system.

i accept it, but personally i think we should be regionalising energy more, and so look forward to solar, methane, biodiesel, woodgas etc more fervently than i do mega-super-ultra icons to bigness, (as well as bizniz), further furthering the control freakery of the usual suspects who have abetted in bringing us to the brink of social collapse, and who have been enabling the daily haemorraging of millions of man-hour-capital-money-units to shady, dubiously motivated, opaque leaders of foreign lands, whose histories do not always encourage happy memories of friendship.

small niggle though, and one we can surely indulge ourselves in at greater length once we have turned the peak oil corner.

the devastatingly intelligent solution of paying farmers to host these beasts is screaming for some pol to ride all the way to the top with.

CAP is so unpopular, yet its motive to keep the people on the land is noble.

5,000 people a day arrive in bombay, to live.

if we don't weave the destiny of rural communities into any national 'economic success story', we risk the (sadly undereported) suicides such as occurring in northern india, as people, without whom we might starve but for their humble toil, are relegated to the back of the economic bus, or left standing at the station.

ghandi's little spinning wheels were greatly symbolic for this reason.

as long as we have energy-hogging cities, i suggest we consider solar panels to be the new spinning wheels, symbolising independence from top-down totalitarianism, where it be of the stalinist, or IMF variety.

we all owe our existence to the generations of farmers, meek or wild, in our ancestries. they deserve respect and support, and right now they get too little of either.

there would be a strange kind of pride for them in their powering the cities, not just with vittles, but also with kilowatts.

the best and brightest from the countryside has been sucked into the gravity of cities for centuries.

isn't it time for the tide to turn?

'The history of public debt is full of irony. It rarely follows our ideas of order and justice.' Thomas Piketty

by melo (melometa4(at)gmail.com) on Sat May 13th, 2006 at 07:35:31 PM EST
Great diary, helping me understand wind power in one easy lesson. As far as I'm concerned diaries on anything to do with the environment are essential.  The rest of the worlds problems aren't going to amount to a hill of beans if we continue to kill the environment off from land, air and sea pollution to not using renewable energies, not using alternative gas solutions, the massive deforestation going on...all of this is truly going to kill us all off.  We are committing slow suicide, yet we already have much of the technology to reverse so much or at least halt the devastation occurring.

"People never do evil so throughly and happily as when they do it from moral conviction."-Blaise Pascal
by chocolate ink on Sat May 13th, 2006 at 11:31:44 PM EST
A big wind farm in the USA can include up to 100 turbines (150 MW) and generate, say, 500 TWh per year, enough to fulfill the needs of 45,000 families.

As a comparison, a typical coal-fired power plant will have a capacity of 600 MW and generate close to 5,000 TWh.

I guess you mean 500 and 5000 GWh, not TWh.

The yearly power consumption of Sweden is 145 TWh. ;)

Peak oil is not an energy crisis. It is a liquid fuel crisis.

by Starvid on Sun May 14th, 2006 at 08:06:05 AM EST

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