LATER this year, when Queen Elizabeth turns 80, she will see a dramatic drop in her electricity bills. This is not a special deal for the UK's senior citizens. The cut in the royal fuel bill will come thanks to a hydroelectric plant on the river Thames, which will start supplying power to Windsor Castle, one of her numerous homes.

The £1 million scheme, which will supply up to 200 kilowatts of electricity, is being developed by the electricity generating company Npower. The generators will be driven by four turbines now being built into Romney weir, about 800 metres from the castle. The generators will make a substantial dent in the royal electricity bill, supplying about a third of the castle's needs. And the cost of the upkeep will be minimal. "Once they're in you can pretty much leave them alone," says Patrick Spink of Npower Renewables, the company installing ...