non-renewable energy and power stations

what are non-renewable energy resources?

• they will all run out one day

• they all do damage to the environment

• they provide a lot of our energy

non-renewable energy sources

• coal

• oil

• natural gas

• nuclear fuels (e.g. uranium and plutonium)

what are the fossil fuels?

• coal

• oil

• natural gas

where is most of the energy we use generated from?

• the four non-renewable energy sources in big power stations

features of a power station

1. as the fossil fuel burns (in oxygen), the energy in its chemical energy store is transferred to the thermal energy store of the water by heating

2. the water boils to form steam, which turns a turbine, transferring energy mechanically to the kinetic energy store of the turbine

3. as the turbine revolves, so does the generator, which produces an electric current- the generator transfers the energy electrically away from the power station, via the national grid

advantages of fossil fuels

• burning fossil fuels releases a lot of energy, relatively cheaply

• energy from fossil fuels doesn’t rely on weather, like a lot of renewable energy, so it’s a reliable source

• we have lots of fossil fuel power stations already, so we don’t need to spend money on new technology to use them

disadvantages of fossil fuels

• all three fossil fuels releases carbon dioxide into the atmosphere when burned in power stations, all this carbon dioxide contributes to global warming and climate change

• burning coal and oil also releases sulfur dioxide which causes acid rain- harms trees and soils and can have a huge impact on wildlife

• they’re eventually going to run out

what is a nuclear power station?

• the same as a normal power station, however nuclear fission (e.g. of uranium), produces the heat to make steam drive the turbines rather than burning

• during this process, energy is transferred from nuclear energy stores to thermal energy stores by heating

• then mechanically to kinetic energy stores, and finally transferred electrically through the national grid

nuclear power advantages

• doesn’t produce any of the greenhouse gases which contribute to global warming

• there’s still plenty of uranium left in the ground (although it can take a lot of money and energy to make it suitable for use in a reactor)

nuclear power disadvantages

• processing the uranium before you use it causes pollution, and there’s always a risk of leaks of radioactive material, or even a major catastrophe like Chernobyl

• there’s always radioactive waste

• when they’re old and inefficient, nuclear power stations must be decommissioned (shut down and made safe) which is expensive

what is wind farming?

• wind power involves putting lots of wind turbines up in exposed places- like on moors, around the coast or out at sea

• they use energy from the kinetic energy store of moving air to generate electricity

• wind turns the blades, which turn a generator inside it

wind power advantages

• renewable- never going to run out

• doesn’t produce any polluting waste

wind power disadvantages

• some people believe they spoil the view as you need about 1500 wind turbines to replace one coal-fired power station, covering a lot of ground and having an effect on the scenery

• can be very noisy- disturbing for those nearby

• sometimes the wind isn’t strong enough to generate any power

• impossible to increase supply when there’s extra demand

• expensive to set up a wind farm especially out at sea

what is geothermal power?

• heat from underground

how does geothermal power work?

• it is only possible in certain places where hot rocks lie quite near to the surface

• the source of much of the energy is the slow decay of various radioactive elements including uranium deep inside the earth

• water is pumped in pipes down to the hot rocks and forced back up due to pressure to turn a turbine which drives a generator

• so the energy is transferred from thermal energy stores to kinetic energy stores and used to generate electricity

geothermal power advantages

• in some places, its used to heat buildings directly

• free, renewable with no real environmental issues

geothermal power disadvantages

• the cost of drilling down several km

• the cost of building a power plant is high compared to the amount of energy we can get out of it

• very few places where this seems to be an economic option, for now

what are solar cells?

• solar cells (photocells) use energy from the sun to directly generate electricity

• they generate direct current

• they’re used to generate electricity on a relatively small scale, e.g. powering individual homes

• but solar farms can also be built- this involves a large area of solar panels which rotate to follow the sun

solar cells advantages

• sun provides a renewable energy source- won’t run out for 5 billion years

• solar cells are expensive initially, but after that the energy is free and running costs are almost 0

• no pollution produced while using them

• useful in remote places like deserts and in satellites

• cells can be linked to rechargeable batteries to create a system that can store energy during the day for use at night

solar cells disadvantages

• some pollution produced during their manufacturing

• solar cells can be connected to the national grid which is expensive

• can only generate enough electricity to be useful if they have enough sunlight- an issue at night and in winter

solar water heating panels

• more simple than solar cells

• they’re just black water pipes inside a glass box

• the glass lets energy from the sun in, which is then absorbed by the black pipes and heats up the water

• like solar cells, they cost money to set up but are renewable and free after that

• only used for small-scale energy production

cooking with solar power

• if you get a curved mirror, then you can focus the sun’s light- this is what happens in a solar oven

• all the radiation that lands on the curved mirror is focused right on your pan

• they provide a renewable energy resource for outdoor cooking

• but they’re slow, bulky and unreliable- strong sunlight is needed for it to work

wave power with wave converters

• one way of harvesting wave power is with lots of small wave converters located around the coast

• as waves come in to the shore, they provide an up and down motion which can be used to drive a generator

• the energy is transferred from the kinetic energy store of the waves to the kinetic energy store of the turbine and used to generate electricity

wave converters advantages

• renewable

• no pollution

• initial cost is high but there are no fuel costs and minimal running costs

• can be very useful on small islands

wave converters disadvantages

• spoils the view

• hazard to boats

• fairly unreliable as waves tend to die when wind drops

• unlikely to provide energy on a large scale

what are tidal barrages?

• big dams built across river estuaries, with turbines in them

• as the tide comes in, it fills up the estuary to a height of several meters

• this water can then be allowed out through turbines at a controlled speed, driving turbines on the way in

• the energy is transferred from the kinetic energy stores of the water to the kinetic energy stores of the turbines and used to generate electrcity

tidal barrages advantages

• no pollution

• renewable

• quite reliable but the height of the tide is variable, lower tides provide less energy than higher ones

• no fuel costs and minimal running costs

tidal barrages disadvantages

• prevents free access by boats

• spoils the view

• alters the habitat of the wildlife

• initial costs are moderately high

how does hydroelectricity work?

• hydroelectric power often requires the flooding of a valley by building a big dam

• rainwater is caught and allowed out through turbines, transferring energy from the gravitational potential energy store of the water

• then to kinetic energy stores as it falls, used to generate electricity

hydroelectric power advantages

• renewable energy source

• no pollution as such

• immediate response to increased demand

• no issue with reliability unless there’s drought

• no fuel and low running costs

hydroelectric power disadvantages

• impact on environment due to flooding the valley (rotting vegetation releases methane and carbon dioxide) and possible loss of habitat for some species

• reservoirs can also look unsightly when they dry up- locations in remote valleys can avoid some of these issues

• initial costs are high

pumped storage

• more large power stations have huge boilers which have to be kept running all night even though demand is very low

• this means there’s a surplus of electricity at night and it’s difficult to keep this spare energy for later which is where pumped storage comes in handy

• in pumped storage, spare night-time electricity is used to pump water up to a higher reservoir

• this can then be released quickly during periods of peak demand to supplement the steady delivery from the big power stations

• the spare electricity is used to transfer energy back to the water’s gravitational potential energy stores so that it may generate more electricity when needed by flowing through the dam