THE POWER OF WATER

We're hooked on fossil fuels. But hydroelectric power is becoming an increasingly important replacement for coal and oil

- IAN OSBORNE

Hydroelectric power meets around 15 per cent of the world’s electricity needs, supplying about a billion people with power – that’s comparable to 3.6 billon barrels of oil. The importance of hydropower will grow over the coming decade, with a huge number of major schemes currently under construction – as of February 2024, there are at least five in China alone. It means that although our reliance on fossil fuels is still significant – it’s a hard addiction to crack, after all – hydropower is helping us decrease our dependence.

Power production is simply a process of converting energy from one form to another. In hydroelectric plants, it’s the ‘potential energy’ of water collected in a dam that eventually ends up as electricity. A pipe known as a penstock runs through the base of the dam. As water rushes through, the potential energy becomes kinetic energy – the energy of motion. This kinetic energy rotates a turbine in the penstock.

The turbine leads to a shaft that in turn leads to a generator. Inside the generator, huge magnets start to rotate past copper coils to produce alternating current (AC) electricity.

Finally, this is changed to a higher voltage using a transformer and delivered to the power grid.