OFFSHORE WIND: Wind turbines cropping up offshore are growing ever larger in size.
Image: Photograph by phault, courtesy Flickr
Whipped by winds exceeding 90 mph and battered by 15-foot waves, hundreds of wind turbines produce electricity off the coast of the North Sea and send it onshore to power homes and businesses in the United Kingdom, Germany and Denmark. Thousands more will be erected in the next 15 years, and bigger will be better as far as turbine makers are concerned.
The top offshore turbine makers, Vestas and Siemens, are preparing for rapid market growth and are developing 7-megawatt and 6 MW turbines, respectively. And General Electric Co. is working on a turbine that could be as big as 15 MW -- five times larger than existing offshore machines.
There's big money to be made in the North Sea, where the U.K. government aims to install 32 gigawatts in offshore wind capacity in its third licensing round between 2015 and 2025. That's more than 10 times the offshore capacity currently installed in the entire world. The U.K. Carbon Trust estimates the offshore wind market will be worth $52 billion by 2020.
"The opportunities in the wind industry are enormous," said Finn Strøm Madsen, president of Vestas Technology R&D. "It's a technology-driven business. From a research and development perspective, it is a very interesting area. Vestas is spending 5.5 percent of its revenue on research and development, which is comparable with Airbus or Boeing."
The 7 MW Vestas V164 turbine has more than double the capacity of the biggest offshore machines today, which are 3 MW. It weighs 800 tons without taking into account the underwater foundation, and its 164-meter (538-foot) rotor sweeps an area three times the size of a football field.
"This is a dramatic technology development because the rotor is so much bigger than anything on the market today," Madsen said. "The control systems and the software are totally new, and the control mechanisms are very sophisticated and advanced compared with existing wind turbines. The blade shape is different and much more efficient. Overall, it drives down the cost of energy by about 40 percent, which is a very important parameter for our customers."
The technical challenge, though, remains daunting.
"These products are standing outside for 25 years, and the speed of the tip of the blade on the V164 is 320 kph [199 mph]" Madsen said. "Nothing else on this planet is experiencing the same enormous stress as this turbine. It's very different from an airplane, which flies 15 hours and then lands again to be serviced. You don't take a turbine down for months."
Bigger is cheaper, but more complex
Bigger turbines generate electricity at a lower cost per kilowatt-hour. Taller is also better because wind speed and consistency increase with altitude. So offshore, you want as big a turbine as possible, with as big a rotor as possible that will run longer. That's impossible onshore, where manufacturers are constrained by the size of roads and bridges over which the turbine parts will have to be transported.
"Producing electricity with wind offshore is more expensive than onshore, just due to the complexity of it," Madsen explained. "This new turbine is dramatically more efficient, so it's narrowing the gap but still not closing it. The cost of energy is still cheaper onshore."
On the other hand, offshore parks generate more power than those on land because winds blow 40 percent more often at sea, according to the European Wind Energy Association.
While Vestas won't have a prototype ready for the V164 until next year, Siemens is already testing its first 6 MW turbine offshore from Denmark, and serial production is expected to begin in 2014.
Aside from the different capacities, the two rival manufacturers are also betting on different technologies. The Vestas machine will be a conventional geared turbine, while the Siemens one operates with direct drive.
In a conventional geared turbine, the rotor turns a large gear, which turns a smaller one, which turns the generator. With direct drive, the turbine directly turns the generator at the same speed as the blades. The generator converts the mechanical energy generated by the blades into usable electrical power. How effective the generator is directly affects how much wind can be converted into electric power. Today, most wind turbines have generators connected to a gearbox.
Several turbine makers sell direct drive machines onshore. Siemens itself has two models. Germany's Enercon is the only company to succeed with a direct-drive turbine so far, but its models are only built for onshore installation.
Vestas looked into using direct drive on the V164 but decided against it. The company says a geared solution is more efficient, uses a lot less rare earth materials and will need to be serviced less often compared with a direct drive turbine. On the other hand, direct drive weighs less.
While in the past the gearbox was the main cause of turbine failures in the industry, now it is electrical systems. And a direct drive turbine has to have four times more electrical components than a geared turbine, which would increase the chance of a malfunction.
It's not only expensive to send technicians to repair turbines at sea, but also physically impossible during bad weather. And a turbine that is not running is costing its operator a lot of cash in energy that it is unable to produce. Siemens says its direct drive machine will require less maintenance than existing models.
Offshore wind turbines cost much more to install and maintain than onshore ones, so reliability is paramount. The machines require special ships to anchor the turbine foundations and build the towers. The Siemens 6 MW prototype even has a helicopter-hoisting platform integrated in the back of the nacelle to allow easy access for service technicians.
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17 Comments
Add CommentHow about bird mortality? Seabird chopper! How about salt corrosion? The maintenance costs will be huge. Maintenance will be difficult to schedule because of weather. This has bad idea written all over it.
Reply | Report Abuse | Link to thisI wonder if they are also planning for the rise in sea levels due to global warming... The blades need to be placed high enough that they will not break the waters surface even in a freak wave condition.
Reply | Report Abuse | Link to thisThe number of bird deaths from wind turbines is insignificant compared to the number killed by vehicles on the highway, flying into closed windows and domestic cats.
Reply | Report Abuse | Link to thisI found this link to a debunking of some George Will foolishness:
http://mediamatters.org/research/201005040009
If those numbers are correct then wind farms account for less than 0.04% of the deaths.
That's nothing compared to domestic cats killing a million birds per day. In the paper "Predation of wildlife by domestic cats Felis catus in Great Britain" the estimate says 9 million cats in Britain kill 27 million birds annually (on top of 57 million mammals and 5 million reptiles) so I think the wind turbines have quite a way to go before they catch up to housecats.
@Leadfoot and @BillR -- The first offshore wind farm went into operation in 1991, and 2 of the 10 largest in the world date back to 2003 and 2003...but, yeah...I'm sure you're right, nobody has given any consideration to maintenance costs, or environmental impacts...these guys just have billions to throw around with no thought nor care as to whether they will make a profit...
Reply | Report Abuse | Link to thisIn other words, Get A Grip!!!
Bravo and Hooray!!! More power, less pollution!!! How can anyone be against that?
Well, lets not go and proclaim offshore wind the savior of the world quite yet, granted 8 years of data is good, but they're wanting 25 years out of these things, and @billr and @leadfoot do have some valid points. However, I for one am in total support of offshore wind until provided with data that suggests that wind turbines are having some truly serious adverse affects on their surrounding environments. I mean they are talking about installing these in the North Sea, why not let the brits test and perfect it first, if there are any real threats to the environment caused by these then I'm pretty sure that they'll let us know.
Reply | Report Abuse | Link to thisThe reason not to let GB (or anyone else) go first is that they'll define and own the market for the generators. Their engineers and operators will have all the experience, their manufacturing facilities will be farther ahead.
Reply | Report Abuse | Link to thisThe turbines are built/owned by private corporations so there's no reason to expect they will share any data about environmental problems any more than BP shared data about the Gulf oil spill.
Wind is good, better than coal or oil but I think solar is the way to go because it can be installed at the point of use. Think of the massive losses in transmission lines to get the power to shore and then to homes and businesses. All those moving parts in the turbines that have to be replaced. That's a lot of resources going into maintenance.
Contrast that with a completely stationary and silent solar array on the roof of a home or business, safe from hurricanes, freighters and icebergs. The newer PV modules have a 20 to 25 year guarantee.
Imagine if solar systems were widespread - not having a power bill would be a major plus when buying/selling a home. Imagine charging an electric car battery for free every day instead of paying for gas.
Solar benefits individuals. Wind, hydro and nuclear only benefit the big energy companies that are currently using coal and oil. I say take a big chunk out of them by slapping a solar array and just using them as a backup supply. They currently have a lot of excess power at night (when businesses are closed and people sleeping), I'd like to see them have a lot of excess power during the day too.
I wonder if these wind turbines can withstand and operate in hurricane wind of over 200 kph. They should design variable wind speed adjustable turbine blades capable of high speed. So the wind turbines can capture the enormous power of hurricanes.
Reply | Report Abuse | Link to thisYes, you got that right without realising it: they have billions of taxpayers' money to throw around without a thought about the economics and environmental impact of wind power. They're called subsidies and without them not one of these things would be built.
Reply | Report Abuse | Link to thisHave any figures on the performance of the existing farms you mention? I'd be interested to see them if you do: for some strange reason it's very difficult to get your hands on any.
Taking it for granted that these things make sense is likely to ultimately cause even more damage to the environment.
Given that there have been ships made of the same stuff as these windmills for a hundred years, I think that there are people who can deal with potential corrosion issues
Reply | Report Abuse | Link to thisFor those who seem concerned about environmental impacts consider; "Offshore Wind Power and Wave Energy Devices Create Artificial Reefs"
Reply | Report Abuse | Link to thishttp://www.sciencedaily.com/releases/2010/01/100118132130.htm
I am no engineer but the tips going 199MPH seems strange. I suppose it is possible that they could get going that fast but it seems to me that would put more energy into the wind than extract it, at least at the tips.
Reply | Report Abuse | Link to thisI completely agree with you. Solar is the best way to go. If you put solar panels on every home and business in America, can you imagine the power we would be generating. The best thing is that these solar panels would be owned by the homeowner and business owner and your would be getting free electricity. The cost of solar panels would drop like a lead balloon and you could even buy them at Lowe's or Targets. Street lights could be converted to diaoid (misspelled) and a solar panel could recharge a battery located in the pole and the light would burn brightly for days - or forever.
Reply | Report Abuse | Link to thisYou could charge your electric car for free and never have to stop at a gas pump ever again. Instead of GE investing all their money in sea turbines, they should invest in those solar parks they already have in several places on the east coast. If you had as many solar parks as you do gas stations; people would never worry about the distance their electric car can go again.
Solar is a win win for everyone.
It's not an either / or between wind and solar. Yes, we should eventually change the roofing industry into the solar instillation industry, allowing us to use our roofs for electricity generation, water heating or for park space. The traditional shingle or steel roof should eventually be replaced by materials that benefit the building's owner and / or tenants. But wind energy is ALREADY cutting power bills in places like Texas and Germany. Yeah, there are line losses and a lot of up-front capital cost, but the energy delivered by a wind turbine is just as carbon and pollution - free as solar power.
Reply | Report Abuse | Link to thisSome people around here complain about subsidies. Well, dirty energy has received 10x - 100x more direct support from governments than clean energy. Market subsidies, production subsidies...the people who claim that dirty energy doesn't receive direct subsidies and support from governments around the world are delusional. Then, if you price in the negative health effects and property damage associated with dirty energy's pollution and climate change effects, clean energy is a clear winner for the Human Race! If they say that pollution doesn't affect our health, I say to them, "stick your mouth on the tailpipe of an idling bus and take a deep breath, then tell me how you feel about pollution's effect on our health."
The market is massively distorted in dirty energy's favor through these direct and indirect supports. The paltry subsidies directed at clean energy are a weak, but important, attempt to restore a little fairness to the energy market.
199 mph = 320 kph = 5,333 meters per minute is actually quite slow considering that the rotor is 164 meters long. One revolution sweeps a circumference of 515 meters so 5,300 meters per minute is about 10 revolutions per minute (rpm). Your electric fan spins a lot faster than that.
Reply | Report Abuse | Link to this@SkepticalKen
Reply | Report Abuse | Link to this> More power, less pollution!!! How can anyone be against that?
If their multi-billion $$$ profits from fossil fuels and nukes are threatened. Or if they blindly think whatever their political puppetmasters tell them to think. ;)
TANSTAAFL means "There Ain't No Such Thing As A Free Lunch" and it applies to ALL forms of energy generation. Coal is a filthy source, oil is just a little better, natural gas a bit better still, nuclear energy,,,well, that's questionable ,,,then there is wave power, wind power, solar cells,,,which all have the problem of intermittency(the wind doesn't blow all the time, waves rise and fall with the tides, the sun doesn't shine all the time).
Reply | Report Abuse | Link to thisThere's always a price to pay. Some prices are just more acceptable than others.
Going through the comments I did not see anything on costs for these wind farms.
Reply | Report Abuse | Link to thisSo, let me add a couple of figures (all this can be found in public documents).
This year there went am Offshore Wind farm in the Baltic sea (the sea east of the North sea) on the grid in Germany (Baltic 1 – you can find it in Wiki).
The installed Power is 50 Mwatt - on a yearly basis it delivers an average of 20 Mwatt.
The planned costs were 150 Million Euro - the actual costs finally were 300 Million Euro
(about 405 Million $).
And - by the way - the costs for the new planned windfarms in the North sea will be higher due to the larger depth where these windfarms are planned.
Now I am going to compare this with the costs of the currently built nuclear facility in Olkiluoto (Finland) (it is an EPR 3 type).
The installed power is 1600 Mwatt, with a capacity factor of 90% (at least) it delivers on a yearly basis 1440 Mwatt.
That is – you need about 70 Baltic1 t Wind farms to deliver the same power.
The planned costs for this Olkiluoto EPR 3 were initially 3 billion Euro and doubled in the meantime to 6 billion Euro.
That is – for 6 billion Euro I get the 1440 Mwatt in Olkiluoto.
To obtain the same power from these 70 Baltic wind farms I run up costs of 70 x 0.3 = 21 billion Euros ( = 28 billion $ ).
Add to these costs the costs for the grid extensions to get the power from northern Germany to the industrial regions in the west and south.
I guess that the amount of steel and concrete for these offshore wind farms is a multiple of the material used for nuclear or gas power stations (for the same power delivery).
The main bottleneck is probably the amount of the rare earth metal Neodym, which is used in the generators of the wind turbines to keep their weight down ( I read somthing of 150 kg per large wind mill). And consider this with the Neodym requirements for our hybrid and coming electric cars.
So – yes – the wind does not send us a bill for the electricity delivered - but in the end the price of electricity from the wind will go through the roof