Vestas is planning to build giant windmills and place them in the North Sea to generate electricity. Via IEEE:

Danish wind power giant Vestas has announced plans for a turbine of giant proportions. The 7-megawatt behemoth is an offshore design; it will rise 135 meters (443 feet) above the waves, and feature a rotor blade that measures a full 80 meters (262 feet).

This isn’t the first turbine to crack 7 MW — that honor probably belongs to Enercon’s E-126 — but it is the first time the world’s biggest wind turbine company raised the bar that high. In an introductory video for the Vestas V164, the company’s technology R&D president Finn Madsen said this is the first turbine “100 percent dedicated to offshore, and optimized for the conditions in the North Sea.”

Most of the existing offshore wind turbines — none of which, of course, are yet spinning in U.S. waters — max out at around 5 MW capacities. Vestas is responsible for a huge percentage of the worldwide offshore wind capacity: as of the end of 2010, the company had installed 580 offshore turbines, for a total capacity of 1407 MW. This accounts for about 43 percent of the world market.

While everyone is gushing about what a feat of engineering it is to construct an insanely big windmill in the North Sea that produces 7MW of electricity.

To put the in perspective how little 7MW of power is in the grand scheme of things, considering how difficult it is to construct massive windmills in the North Sea, look at the Zeeland, Michigan natural gas peak load generator.

The 30 acre (on dry land- go figure) Zeeland natural gas peak load generator can provide 930MW of power, enough electricity to serve a community of about 800,000 people. Since this is a peak load station, it can provide this power on demand (minutes) and is not dependent on the weather.

Of course, these giant windmills will require the wind to blow to create electricity. But, the wind can’t be too strong either, because it might cause damage to the windmill.

Of course, building any turbines, let alone truly enormous ones, in offshore conditions is difficult. As Peter Fairley has reported here, wind conditions around the world could be changing and making it even more challenging; increasing dangerous gust conditions could require big turbines like the new Vestas entry to shut down to avoid damage more often than in the past.

Why are the wind conditions changing? Global warming… I mean climate change of course. And these ‘changes’ are causing trouble for windmills:

Young and collaborators at Melbourne’s Swinburne University of Technology created a global picture of offshore wind trends by mining 23 years of nearly continuous data from satellite-based altimeters. The biggest trend they found was a stiff boost in winds gusting in the 99th percentile for wind speeds, which have been increasing over most oceans by at least three quarters of one percent per year.

Those winds pack lots of extra energy, since the energy in wind increases with the cube of its speed. But it’s extra energy that’s worse than wasted on wind turbines, which must feather their blades and shut down to avoid being damaged by extreme winds

This is a lot of effort for very little electricity.