About this blog

Physics can be difficult to learn, but this blog aims to help you get into physics by connecting your GCSE physics lessons with things you see in the world around you.

Thursday, 5 January 2012

Water Water Everywhere

Rain and wind, that’s all we seem to get at the moment, morning, noon and night. Wouldn’t it be nice if we could actually benefit from the elements rather than just complaining about them? This is where renewable energy generation comes in. Unlike solar power, wind and rain are more frequently abundant when we need the most power, when we’re cold during the winter.

Wind turbines and hydroelectric power (the posh name for electricity from water) stations have their origins centuries ago when windmills and watermills were both used to process grain into flour, which is where the “mill” part of the name comes from. Turning your energy source into mechanical motion is a nice and efficient way of using the energy, but there’s no way of storing it or sending it elsewhere if you have too much to use.

So turning the power of wind and water into electricity makes it much easier to share, although it’s still pretty tricky to store. Good job it seems to be windy and rainy all the time then! But how do we go about getting electricity from the wind or the rain? It’s not like you can just hang your plug out of the window and get it that way!

Remember how we learned about getting electricity from fossil fuels (previously)? Well this works just the same, but rather than burning the fossil fuel to make steam to turn the turbines, the water or the air turns them directly.

This can be problematic though, because whilst you can accurately control the steam pressure when you’re burning the fuels, there are no such controls on the elements. It’s usually a trade-off between getting some power out when there’s not such a high flow, and making sure that you don’t have the turbines running too fast when the winds are howling or the water is racing.

Wind turbines are often geared towards moderate winds, so you’ll notice that sometimes when it’s too windy that the turbines are switched off. This is partly for health and safety but also because they just can’t cope when the gusts are really racing, but they can generate electricity in all but the most still conditions.

Water is easier to control, because you can build dams, but that can get costly and people don’t tend to like it when you flood the valley that they live in! There are also many more types of water powered electricity generators, with things like power from the tides, underwater currents in the sea, and storm water becoming increasingly likely to be a big player in the future of renewable energy.

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