Geo-Thermal Power

Wind Power

Wave Power

We can collect it in space.

We can collect it on Earth.

We can use it directly.

Solar Power

More energy arrives at the Earth's surface in one hour than man uses in one year. This clean, natural energy comes from sunlight and it's called solar power. The question is... how can we use it to replace fossil fuels and nuclear energy? There are three answers.

Many modern buildings have big windows which face south. These collect solar power directly. In fact some buildings in North America and Scandinavia get 100% of their energy from the sun.

Another way to collect the sun's power is with solar panels. These absorb and store energy on sunny days. But there are two problems with solar panels on Earth, (a) They're expensive, (b) They don't work very well on cloudy days.

One answer to the problems of clouds is to collect solar power in space. The idea is expensive, but simple. Satellites with huge solar panels collect the sun's energy. Then they send it back to Earth. A series of satellites like this will be able to work for 24 hours a day.

25% of the world's electricity already comes from dams and rivers. Now, scientists are learning how to use the sea's power, too. What they're doing is collecting the energy contained in waves. Here's how it works.

First, water enters a special wave machine. This pushes all the air in­side the machine up to the top. Then the water leaves again and pulls the air back down. This pushing and pulling makes enough energy to work an electric motor. At the moment wave machines are small and expen­sive. They don't produce much electricity, either. But in the future they will be bigger and cheaper. One day scientists think they will produce between 25% and 30% of our electricity.

Several 'wind farms' already exist in Britain and other European coun­tries. Each farm is a group of machines which turn wind power into elec­tricity. The idea is popular in America, too. California, for example, ex­pects to get 10% of its electricity from wind farms by the year 2000.

The problem at the moment is money. It's very expensive to develop and build wind farms. That's because they have to be in high places near the coast or on islands. This makes their electricity expensive, too. But in the future, electricity from fossil fuels and nuclear power will begin to cost more and more. Perhaps then wind farms won't look so expensive after all.

As well as solar, wind and wave power, there are other kinds of natu­ral energy, too. One is from the hot rocks and water at the centre of the Earth. This kind of 'geo-thermal' energy already heats thousands of build­ings in Iceland, Hungary, Japan and New Zealand. (In fact, 60% of Iceland's energy comes from under the ground.)

□ The solution

So... what's going to happen in the 21st century? Will energy from •the sun • the wind • the sea • under the ground, take the place of fossil fuels and nuclear energy completely? The answer is probably no, but natu­ral energy will become more and more important. That's because:

— It will become cheaper

— It will be better for the environment

— It will make it possible to conserve fossil fuels

— It will be safer than nuclear power.

□ Your opinion

1. Nuclear experts say it's safe to bury radioactive waste. Other scientists aren't so sure. Many think it will seriously pollute the sea or the Earth one day.

What d'you think of it?

2. Green organisations all over the world are against nuclear energy. In their opinion it's dirty, unhealthy and dangerous.

What's your opinion?

Дата добавления: 2015-05-24