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in HEP the infrared radiation in the sun's rays causes the water in lakes , rivcers etc. to evapourate , this water vapour :
climbs in height and eventually condenses and falls as rain on high ground . this is collected behinds dams and electrical energy is created as the water falls back via turbines
what are the advantages of HEP
- hydroelectric schemes dont cause pollution
- hydroelectric schemes are generally very reliable
- they can also be started up very quickly to meet sudden increases in the demand for electricity
what are the disadvanatges of HEP
- few areas of the worl are very suitable
- they alter the landscape , and they upset the balance of local plant life by the destruction of wildlife habitats
- hydroelectric schemes involve damming upland river valleys , this means flodding land that may have been previously used for farming or forestry
HEP - water in the resevoir is at a high level and has ..... ..... energy . As the water falls to a lower level this energy is converted into ..... energy of the flowing water . As the water flows through the turbine it slows down losing its kinetic energy which is converted into the ...... energy , this time of the turbine which rotates . The generator converts the .... energy of the turbine into ..... energy which can be transmitted to the consumer
- gravitational potential
HEP - intial costs are .... , but there's ... ... and ..... running costs
what are pumped storage systems
they aren't really a means of generating electrical power . they're a way of storing energy so that we can release it quickly when we need it .
demand for electrical power changes throughout the day for example , when a popular TV programme finishes , a huge number of people go out and put the kettle on causing a sudden peak in demand . this is called a :
following a TV pickup , if power station sdont generate more power immediately , there'll be :
power cuts all around the country - traffic lights will go out , causing accidents , and all sorts of other trouble will occur .
following a TV pickup , if power station sdont generate more power immediately , there'll be power cuts all around the country - traffic lights will go out , causing accidents , and all sorts of other trouble will occur . the problem is most of power is generated by fossil fuel power stations , which :
take half an hour or so to crank themselves up to full power . Nuclear power stations take even longer . we need something that can go from nothing to full power immediately , and keep us supplied for around half an hour until the other power stations catch up . this is where pumped stroage systems come in
describe the process of a pumped storage system
- water is pumped up to the top reservoir at night , when demand across the country is low .
- When thers's a sudden demand for power , the "headgates" (huge taps) are opened , and water rushes down the tunnels to drive the turbines , which drive powerful generators
- the water then collects in the bottom reservoir , ready to be pumped back up later
pumped storage uses the same idea as :
HEP but it isnt a way of generating electricity - its simply a way of storing energy which has already been generated