Physics 1b

Non-renewable energy resources are resources that won't last forever, they damage our environment and they are: coal, oil, natural gases and nuclear fuels.

Renewable energy resources will never run out, most of them damage our environment (but less harmful than non-renewables) and they are: wind, waves, tides, hydroelectric, solar, geothermal, food and biofuels.

The fossil fuel is burned to convert its stored chemical energy into heat (thermal) energy. The heat energy is used to heat water to produce steam, the steam turns a turbine, it converts heat energy into kinetic energy. The turbine is connected toa generator, whic transfers kinetic into electrical.

A nuclear power station is mostly the same as the other, but with nuclear fission of uranium and plutonium producing heat to make steam to drive the turines. They have the longest start up time, where as natural gas stations have the shortest of all the fossil fuels.

This involves lots of little windmills in exposed places. Each turbine has its  own generator, the electricity is generated directly from the wind turning the blades. There's no pollution, but they do spoil the view, you need about 1500 turbines to replace one coal fired power station. They can be very noisy and can cause problems when the wind stops.

Solar cells generate electric currents directly from sunlight. Solar power is often in remote places where theres not much choice, and to power road signs and satelites. Theres no pollution and in sunny country they are a very reliable source, but only in day time. Costs are high, but afterwards energy is free and running has very low costs. It wouldn't be very practical to connect them to the national grid.

Hydroelectric power usually requires flooding of a valley by building a big dam. In a dam, rainwater is caught and allowed out throught turbies, theres no pollution but there's a big impact on the environment due to the flooding of the valley it causes losses of habitation for some species. It can provide an immediate response for increased demand of electricity. There's usually no problems with reliability, minmal running costs.

Most large power stations have huge boilers which have to keep running all night, even though demand is low. Its difficult to store the spare energy, so they usePumped storage. 'Spare' night electricity is used to pump water up to a high reservoir. It can then be released quickly during peak times of demand, such as tea time. It's a way of storing energy which has already been generated.

Wave power requires lots of little wave-powered turbines located around the coast. As waves come into a shore they create an up, down motion, which is used to drive a generator. There is no pollution, the main problems are spoiling the view and hazardous to boats. However they are fairly unreliable.

Tidal power is where big dams are built across river estuaries with turbines. When the tide comes in, it fills the estuary to a height of several metres and drives the turbine. The water can then be allowed through at a controlled speed. The source of energy is the Gravity, the Sun and the Moon, so there is no pollution but it can cause problems for boats and habitats.

This is only possible in volcanic areas where there are hot rocks near the surface. The source of much of the heat is slow decay of various radioactive elements, including Uranium. Steam and hot water rise to the surface and drive a generator. It's free energy with no real environmental problems. In some places it's used to heat buildings directly,  although there aren't many suitable locations for plants.