Renewable Energy sources
Today petroleum provides around 40% of the world’s energy needs, mostly fuelling automobiles. Coal is still used, mostly in power stations, to cover one-quarter of our energy needs, but it is the least efficient, unhealthiest and most environmentally damaging fossil fuel. Natural gas reserves could plug some of the gap from oil , but reserves of that will not last into the 22ed century either. Most experts predict we will exhaust easily accessible reserves within 50 years. We could fast reach an energy crisis . We need to rapidly develop sustainable solutions to fuel our future. Less-polluting renewable energy sources offer a more practical long-term energy solution .They may benefit the world’s poor too .〝Renewable〞refers to the fact that these resources are not used faster than they can be replace .
The Chinese and Romans used watermills over 2,000 year ago .but the first hydroelectric dam was built in English in 1870 .Hydroelectric power is now the most common form of renewable energy ,supplying around 20% of world electricity .China’s Three Gorges Dam , which has just been completed ,is the largest ever . At five times the size of the US’s Hoover Dam ,its 26 turbines will generate the equivalent energy of 18 coal-fired power stations .It will satisfy 3% of China’s entire electricity demand . Surprisingly , some argue that hydroelectric dams significantly contribute greenhouse gases .
In 2003 , the first commercial power station to harness tidal currents in the open sea open sea opened in Norway . It is designed like windmill , but others take the form of turbines .
As prices fall , wind power has become the fastest growing type of electricity generation—quadrupling worldwide between 1999 and 2005 . Modern wind farms consist of turbines that generate electricity . Though it will be more expensive , there is more than enough wind to provide the world’s entire energy needs . Wind farms come in onshore an offshore forms . They can often end up at spots of natural beauty , and are often unpopular with resident . And turbines are not totally benign –they can interfere with radar and leave a significant ecological footprint , altering climate and killing sea birds . Migrating birds may have more luck avoiding them . Scotland is building Europe’s largest wind farm , which will power 200,000 home . The UK’ goal is to generate one-fifth of power from renewable sources , mainly wind , by 2020 . But this may cause problems , because wind is unreliable .
可再生资源
今天石油提供了大约40%的世界的能源需求,主要是推动汽车。

煤是仍然使用,主要是在发电站,覆盖有四分之一的能源需求,但我们,这是最有效和最破坏力之一化石燃料。

天然气储备能插的一些差距,但从石油储备,将不会持续到22艾德世纪都无所谓了。

大多数专家预测,我们将排气容易可存取的储备在50年。

我们可以快速达成的能源危机。

我们需要迅速发展可持续的解决方案来推动我们的未来。

Less-polluting可再生能源提供一个更实际的利益。

他们可能长期能源解决世界上的贫穷也是。

“再生”指的是事实,这些资源没有被使用的速度比他们能被换掉。

中国和罗马人用watermills超过2,000年前,但是第一个用于水力发电的水坝始建于英语1870年.Hydroelectric权力是现在最常见的可再生能源,提供电力,约有20%的世界.中国的三峡大坝,刚刚完成后,是有史以来规模最大的。

在五倍大的美国的胡佛大坝,它会产生相当于26个涡轮机的能量,这将18燃煤电站3%中国满足全部用电需求。

令人惊讶的是,一些人争辩说水
力发电站显著贡献的温室气体。

在2003年,第一个商业电站利用潮流可在大海大海开在挪威。

它的设计是像风车,但别人以不同的形式的涡轮机。

当价格下降时,风力发电已成为发展最快的类型的电generation-quadrupling 1999年至2005年世界范围内。

现代风力发电设施包括涡轮发电。

虽然它将会变得更加的昂贵,有足够多的风提供到整个世界的能源需求。

风力发电厂进来陆上近海的形式。

他们往往会最终在景点的自然。