In eighteen seconds two gentle swooshes of a giant wind turbine can power your home’s electricity for the day. Just two swooshes, and your devices will glow, lights shine, and electric ovens purr with warmth. There’s no pollution. The wind smells only of cold damp pasture, moss and the sea. Nature. In raw, beautiful action.
The wind is persistent and chilling in December in the remote Brechfa Forest on the hills of South Wales. One hundred and forty five metres overhead giant turbine blades rotate almost silently. Twenty eight of these vast steel stalks are nested here. A barely perceptible whine from the turbines lets you know that these leviathans are generating power for the grid, for your home and mine.
The wind turbines tower above Brechfa forest
These giant wind-powered towers are painted and sealed to bear all weathers. Glinting aluminium tips on the sails conduct away lightning strikes. We’re “lucky” with the weather as “normally you can’t stand straight for the driving rain, or see the top for the mist.” Well that’s what our guide from Innogy, Mike, tells us anyway.
Provided the wind is blowing at more than six miles an hour these turbines can generate up to 57.4 MWh of power. Anemometers detect wind speeds and direction for automated trimming. If the wind is any higher than twenty five miles per hour — or when a storm blows in — the blades rotate to allow the wind to pass and the generator disconnects.
Transformers step-up the turbines’ 650 volts to 33,000 volts to go into the national grid. Danger of Death signs cover the substation. Everything is monitored closely on site and remotely. The fibre communications link is as important as the electricity grid.
Harnessing the skies is an exercise in scale. Taller turbines, higher up, with larger blades, are more efficient. The new units can fit up to four people within the hub of the blades. To get to the top there are lifts rather than stairs. A welcome innovation, site manager Mike had lost over a stone daily climbing up and down sweltering stairwells in last summer’s heatwave.
The wind farm is part of the agricultural landscape; Brechfa is a working forest. The masts and blades were made in Germany. The people and materials for their construction were nearly all local. It was years in planning. Two hundred and fifty lorry loads brought the masts and blades up to the top of the hill, escorted in police convoys through the windy roads. We heard of a lost lorry overseas that missed its turning and took two weeks to get back.
We were kindly hosted by Innogy UK and shared our visit with neighbours of their farm and university students. Sadly, we couldn’t climb up a turbine as its a three day health and safety course for employees only.
I really enjoyed seeing this wind farm up close, to get a sense of the scale and operation in supplying fresh clean, renewable electricity to the nation’s grid. And to see the farm to which my and your plugs and cables eventually lead.