Energy inside a Welsh mountain

One of the biggest power-stations in the world is being built in the heart of a Welsh mountain. It uses neither oil nor coal to produce electricity, but the water of a large mountain lake.

In a few thousand years people may discover the machines and wonder what had been happening there. Chief engineer Bill Thompson says that some may think that it was a church. Certainly the large mountain caves remind us of a magnificent cathedral, especially when they are quiet. However, they are usually full of noise: vehicles thundering through the dark tunnels, the noise of pumps, hammering and shouting.

The underground pumped power station is the largest in Europe and is used to produce electricity by pumping water again and again between two lakes. The water is let out through the bottom of the top lake, Machlyn Mawr, and then it passes down to drive the turbines inside the mountain. The water turns the turbines which produce electricity. Afterwards the water is collected in the bottom lake, Llyn Peris, at the foot of the mountain in the heart of Snowdonia. The turbines then change direction and work as pumps, returning the water to the top lake, ready to be used again.

Susan Sheerin, Jonathan Seath, Gillian White: Spotlight on Britain; Oxford University Press, 1985, page 99

People often speak of the 'energy crisis' because the world may be running out of energy. What do you think are the best ways of using coal, oil, gas and electricity more efficiently?

What other forms of energy could people use - for example, solar power, wind and wave power, nuclear power?

Is nuclear power the best way to solve the energy crisis?