Energy Sources

Energy Sources

1. Wind and Solar

   • Wind power
     • 1) This involves putting lots of windmills (wind turbines) up in exposed places like on moors or round coasts
     • 2) Each wind turbine has it's own generator inside it so the electricity is generated directly from the wind turning the blades, which turn the generator
     • 3) There's no pollution (except for a little bit when they're manufactured)
     • 4) But they do spoil the view. You need about 1500 wind turbines to replace one coal-fired power station and 1500 of them cover a lot of ground - which would have a big effect on scenery
     • 5) And they can be very noisy, which can be annoying for people living nearby
     • 6) There's also the problem of no power when the wind stops, and it's impossible to increase supply when there's extra demand
     • 7) The initial costa re quite high, but there are no fuel costs and minimal running costs
     • 8) There's no permanent damage to the landscapes - if you remove the turbines, you remove the noise and the view returns to normal
   • Solar cells
     • 1) Solar cells generate electric currents directly from sunlight. They'er expensive initially. Solar cells are often the best source of energy for calculators and watches which don't use much electricity
     • 2) Solar power is often used in remote places where there's not much choice (e.g. the Australian outback) and to power electric road signs and satellites
     • 3) There's no pollution (Although they do use quite a lot of energy to manufacture in the first place)
     • 4) In sunny countries solar power is a very reliable source of energy - but only in the daytime. Solar power can still be cost-effective even in cloudy countries like Britain
     • 5) Initial costs are high but after that the energy is free and running costs almost nil
     • 6) Solar cells are usually used to generate electricity on a relatively small scale, e.g. powering individual homes
     • It's often not practical or too expensive to connect them to the National Grid - the cost of connecting them to the National Grid can be enormous compared with the value of the electricity generated

2. Wave and Tidal

   • Wave power
     • 1) You need lots of small wave-powered turbines located around the coast
     • 2) As waves come in to the shore they provide an up and down motion that can be used to directly drive a turbine, which then drives a generator
     • 3) There's no pollution. The main problems are spoiling the view and being a hazard to boats
     • 4) They are fairly unreliable, since waves tend to die out when the wind drops
     • 5) Initial cost are high, but there are no fuel costs and minimal running costs. Wave power is never likely to provide energy on a large scale, but it can be very useful on small islands
   • Tidal barrages
     • 1) Tidal barrages are big dams built across river estuaries, with turbines in them
     • 2) As the tide comes in it fills up the estuaries to a height of several metres - it also drives the turbines. This water can then be allowed out through the turbines at a controlled speed
     • 3) The source of the energy is the gravity of the Sun and the Moon
     • 4) There's no pollution. The main problems are preventing free access by boats, spoiling the view and altering the habitat of the wildlife, e.g. wading birds, sea creatures and beasties who live in the sand
     • 5) Tides are pretty reliable in the sense that they happen twice a day without fail, and always near to the predicted height. They only drawback is that the height of the tide is variable so lower (neap) tides will provide significantly less energy than the bigger 'spring' tides. They also don't work when the water levels is the same either side of the barrage - this happens four times a day because of the tides. But tidal barrages are excellent for storing energy ready for periods of peak demand
     • 6) Initial costs are moderately high, but there are no fuel costs and minimal running costs. Even though it can only be used in some of the most suitable estuaries tidal power has the potential for generating a significant amount of energy