April 05, 2008
Floating Platforms Could Cut Cost Of Offshore Wind Power

Some sources put the cost of offshore wind power at twice the cost of onshore installations. Yet the British government has announced plans to do big offshore wind farm builds. Companies in the Netherlands, Norway, and other countries might slash the cost of offshore wind by using floating platforms.

Offshore wind-farm developers would love to build in deep water more than 32 kilometers from shore, where stronger and steadier winds prevail and complaints about marred scenery are less likely. But building foundations to support wind turbines in water deeper than 20 meters is prohibitively expensive. Now, technology developers are stepping up work in floating turbines to make such farms feasible.

Noise and high spinning speeds have 2 blade turbines undesirable on land. 3 blade turbines get used on land instead. But offshore the trade-offs change and the advantages of 2 blades include lower costs due to a lighter structure.

Faster rotation also means less torque, meaning that the entire structure can be built lighter. (See "Wind Power for Pennies.") The rotor, gearbox, and generator of Blue H's 2.5-megawatt turbine will weigh 97 tons--53 tons lighter than the lightest machine of the same power output on the market. "This is a big advantage," says Jakubowski. "For us, weight on top is something we have to push up." The turbine and platform are correspondingly cheaper to build, he says. The net result, says Jakubowski, should be a highly competitive energy source. He estimates that Blue H's wind farms will deliver wind energy for seven to eight cents per kilowatt-hour, roughly matching the current cost of natural gas-fired generation and conventional onshore wind energy.

Natural gas prices will go up as natural gas fields get depleted. So wind could become preferred with natural gas relegated to back-up when the wind doesn't blow.

Share |      Randall Parker, 2008 April 05 10:21 PM  Energy Wind

Wolf-Dog said at April 6, 2008 6:41 AM:

Hillary Clinton is firmly in favor of solar and wind power. Apparently, she is aiming at increasing the percentage of electricity from wind, solar and biomass to 25 % by the year 2025. By 2025, the wind, solar and biomass derived electricity might be enough to charge 300 million electric cars every day. (I derived this estimate by considering the fact that 20 % of the electricity is nuclear in the United States, and 100 reactors of 100 Megawatt capacity would be enough to charge 300 million electric cars.) By 2025 electric cars would almost certainly be ready.


philw1776 said at April 6, 2008 9:17 AM:

The biggest opposition to offshore wind power is not technical or economic, it's from the elite, beautiful people with oceanfront property and sail craft. In MA, 'environmentalist' Senators Ted Kennedy and John Forbes Kerry have opposed Cape Win's wind farm proposal for years.

Gurgle said at April 6, 2008 9:24 AM:

I hope all the fish appreciate all that expensive electricity we'll be providing them. Maybe the Chinese can build waterproof televisions to keep them entertained and give them something to do while being eaten by bigger fish.

Seriously, what are their voltage drop calculations for 32 km seabed powerlines?

Randall Parker said at April 6, 2008 11:15 AM:


The idea behind these floating platforms is they can get stationed further away from shore and in areas with heavy wind. That will, as a side effect, put many of them out of sight of the shore line. So maybe our masters will let them get put up.

Fat Man said at April 6, 2008 5:18 PM:

Of course ships never sink. And there are no storms with 150 mph winds and 100 ft waves off-shore. Wind mills are a newer technology than ship building by several millenniums. Why is it that nobody ever did this before?

Randall Parker said at April 6, 2008 5:35 PM:

Fat Man,

The learning that makes possible this sort of approach took place in the oil industry. You could ask your same rhetorical question of the oil industry if you wanted to go back in a time machine before they did it.

The oil industry was operating 30 floating oil rigs as of 2005:

Take Thunder Horse, for instance, the $5 billion semisubmersible platform 150 miles southeast of New Orleans. It is about 50 percent larger than the next largest such rig in the world and includes more than 100 technical firsts that will enable it to process 250,000 barrels of oil and 200,000 million cubic feet of natural gas per day - enough to supply 6.5 million American homes with energy.

It is one of only 30 floating platforms in the world and stays upright through a complex system of ballast tanks that pump water back and forth. It is held in position by 16 mooring lines anchored to the sea floor.

And while it was tipping 20 percent after hurricane Dennis, MMS findings have shown that rigs built before 1978 with lower decks and weaker joints are more susceptible to powerful storms.

Fat Man said at April 6, 2008 7:43 PM:

"Thunder Horse, for instance, the $5 billion semisubmersible platform 150 miles southeast of New Orleans."

Only $5*10E+9. And how much electricity will a platform like that produce?

Randall Parker said at April 6, 2008 8:08 PM:

Fat Man,

Thunder Horse has to be big enough to hold a hotel for its workers and huge drilling rigs plus a helicopter platform and fuel for the drilling equipment. Look at the quantities of natural gas and oil it can process.

James K.T. said at April 6, 2008 8:10 PM:

Probably would be a better idea to invest in wave farms if you're going that far out:


Fat Man said at April 7, 2008 5:35 PM:

Randall: Thunder Horse is no doubt a modern wonder, but it is a $5 billion wonder. We expect technology to produce declining costs, but, Thunder Horse was not a product of new technology. The technology that produced Thunder Horse is one of the oldest technologies, the building of ships.

When I was in the insurance industry a quarter of a century ago, we procured insurance on some of the biggest rigs then used in the North Sea and the Gulf of Mexico. IIRC, those rigs were valued at one or two billion dollars each. Thunder Horse is in the ballpark when you include inflation.

Bottom line here is that ocean going platforms are expensive. One of the gripes about nuclear is that it is expensive, and that because it uses large amounts of steel and concrete it will get more expensive.

Well, the same is true for solar and wind. They will be expensive to build. 300 foot tall towers, frames to cover square miles of desert, ocean going platforms, etc., etc. will cost huge amounts of money. And on top of that, if we have to rely on non-continuous power, we need to have energy storage systems. They may be as simple as blocks of ice, but they will cost something, and at the scale of the entire country or the planet, it will be a lot.

Nick G said at April 7, 2008 5:35 PM:

"Probably would be a better idea to invest in wave farms if you're going that far out"

I don't know why you wouldn't do both, and take advantage of the synergy of shared transmission and moorings.

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