The new wind turbines at Good Energy's Delabole wind farm are very impressive. I visited on Tuesday for the celebration of its repowering and learnt a lot about how wind generation has improved.

There are four new wind turbines, replacing the original 10. Delabole, in Cornwall, is the site of one of the first (maybe the first) commercial wind farms in the UK. The turbines are huge, but (in my view) very elegant - maybe that's because the nacelle (which is the egg-shaped bit behind the sail) is designed by Norman Foster.

What's most impressive though is that the four turbines generate two and a half times as much electricity as the original 10 did. They start generating in a gentle breeze, turning with wind speeds as low as 2.5 metres per second.

The other thing that surprised me was how quiet they are. When you're actually inside the tower they make a rather unpleasant whine, but standing at the bottom, just five or 10 metres away I didn't notice any noise at all. This is because increasingly wind turbines are made without gears. They use an inverter to convert the direct current electricity to the alternating current used by the grid. This means that the speed the blades turn is determined by the wind speed, and the generator spins with the blades.

The benefits are that they need much less maintenance, as there is less wear and tear, and they are much quieter. I'm confident that a visit to Delabole would win many a wind sceptic over.

The local community in Delabole appear enthusiastic about the wind farm. The turbines have been named by children from the primary school. I'm sure that Guinevere, Martha, Thomas and Titch will be kicking out lots of power for years to come.

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