共用题干 第一篇

Renewable Energy Sources

Today petroleum（石油）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（矿物燃料）.Natural gas reserves could fill some of the gap from oil,but reserves
of that will not last into the 22^nd century either. Most experts predict we will exhaust easily
accessible reserves within 50 years.Less-polluting renewable energy sources offer a more
practical long-term energy solution."Renewable"refers to the fact that these resources are
not used faster than they can be replaced.
Hydroelectric（水力发电的）power is now the most common form of renewable energy,
suDDIvina around 20%of world electricity.China"s Three Gorges Dam is the largest ever.
At five times the size of the US"s Hoover Dam, its 26 turbines（涡轮机）will generate the
equivalent energy of 18 coal-fired power stations.It will satisfy 3% of China"s entire
electricity demand.
In 2003. the first commercial power station to use tidal（潮汐的）currents in the open
sea opened in Norway. It is designed like windmill（风车）,but others take the torm of
turbines.
As prices fall,wind power has become the fastest growing type of electricity
generation一quadrupling（翻两番）worldwide between 1999 and 2005. Modern wind farms
consist of turbines that generate electricity.Though it will be more expensive,there is more
than enoucih wind to provide the world"s entire energy needs.Wind farms come in onshore
and offshore forms.They can often end up at spots of natural beauty,and are often
unpopular with residents.And turbines are not totally harmless一they can interfere with radar,
alter climate and kill sea birds.Scotland is building Europe"s largest wind tarm,wnicn will
power 200.000 homes.The UK"s goal is to generate one-fifth of power from renewable
sources,mainly wind,by 2020.But this may cause problems,because wind is unreiiable. According to the passage,which of the following is the most polluting energy resource?