06/03/2016 Generating Electricity New Bridge AcademyScience Dept. (AQA)

06/03/2016Fuels A “fuel” is something that can be burned to release heat and light energy. The main examples are: Coal, oil and gas are called “fossil fuels”. In other words, they were made from fossils. We say they are NON-RENEWABLE.

06/03/2016 Using non-renewable fuels in power stations 1) A fossil fuel is burned in the boiler 2) Water turns to steam and the steam drives a turbine 3) The turbine turns a generator 4) The output of the generator is connected to a transformer 5) The steam is cooled down in a cooling tower and reused

06/03/2016 Nuclear power stations These work in a similar way to normal power stations, nuclear is NON RENEWABLE. The main difference is that the nuclear fuel is NOT burnt – it is used to boil water in a “heat exchanger”

06/03/2016 Start up times Different power stations have different start up times: Gas Oil Coal Nuclear Quick Slow

06/03/2016 Some definitions… A renewable energy source is clearly one that can be _______ (“renew = make again”), e.g. _____, solar power etc. A ___________ energy source is one that when it has been used it is gone forever. The main examples are ____, oil and gas (which are called ______ ____, as they are made from fossils), and nuclear fuel, which is non- renewable but NOT a fossil fuel. Words – non-renewable, coal, fossil fuels, wood, renewed

06/03/2016 Non-renewable energy sources Coal, oil, gas and nuclear AdvantagesDisadvantages Cheap fuel costs Short start-up time for gas and oil Good for “basic demand” Fuel will run out Costs a lot of money to decommission a nuclear plant Pollution – CO 2 leads to global warming and SO 2 leads to acid rain Reliable Nuclear produces little pollution

06/03/2016 Other ways of generating electricity Can we drive the turbine directly without burning any fossil fuels?

06/03/2016 Wind Power

06/03/2016 Tidal Power High tide Low tide

06/03/2016 Wave Power

06/03/2016 Hydroelectric Power

06/03/2016 Renewable energy sources summary Wind, tidal, hydroelectric and solar AdvantagesDisadvantages Zero fuel costs Hydroelectric is good for a “sudden” demand Don’t produce pollution Tidal barrages destroy the habitats of wading birds and hydroelectric schemes involve flooding farmland Unreliable (except for hydroelectric) Expensive to build Solar is good for remote locations (e.g. satellites)

06/03/2016 Other renewable options… Geothermal energy – water is heated using heat given off by _________ rocks underneath the surface of the Earth Although renewable fuels are ____, the energy we get from them is “_______”. This means that we have to spend a lot of money on generators to make them worthwhile. This is why solar panels are only used in small things (like calculators) or extremely remote locations (like ____________). Words – dilute, radioactive, free, satellites, light Solar energy – using solar panels ______ can be converted straight into electricity

06/03/2016 The National Grid Electricity reaches our homes from power stations through the National Grid: If electricity companies transmitted electricity at 240 volts through overhead power lines there would be too much ______ loss by the time electricity reaches our homes. This is because the current is ___. To overcome this they use devices called transformers to “step up” the voltage onto the power lines. They then “____ ____” the voltage at the end of the power lines before it reaches our homes. This way the voltage is _____ and the current and power loss are both ____. Words – step down, high, power, low, high Power station Step up transformer Step down transformer Homes