P3.3 Which energy sources should we choose?
| Ways to save energy | ||
| In the home | In the workplace | National context |
| ● More efficient appliances, e.g. a condensing boiler could save £190 per year
● Double glazing – possible savings of £130 per year ● Loft insulation – possible savings of £145 per year ● Cavity wall insulation – possible savings of £110 per year ● Draught-proof rooms – possible savings of £25 per year |
● Cleaning air conditioner filters – can save 5% of the energy used in running the system
● Using low-energy light bulbs ● Roof insulation/cavity wall insulation in modern buildings ● Use of efficient modern, low energy machinery ● Use of modern, efficient vehicles for transport of goods |
● Replacing old houses with new efficient ones
● Increased use of public transport ● More efficient trains and buses ● Encourage more widespread recycling ● Encourage car sharing and fewer journeys |
Coal, oil and gas are energy sources that are formed over millions of years from the remains of plants and animals – they are called FOSSIL FUELS and are responsible for most of the energy that we use. However, because they cannot be replaced within a lifetime, they will eventually run out. These are called NON-RENEWABLE energy sources.
As they demand for electricity continually increases, other sources of energy are needed. RENEWABLE energy sources are those that will not run out because they are continually being replaced
The choice of energy source for a given situation depends upon a number of factors including:
- Environmental impact
- Economics
- Waste produced
- Carbon dioxide emissions
These Non-renewable sources of energy provide most of the electricity we need in this country:
| Source | Advantages | Disadvantages |
| Gas | ● Enough natural gas left for the short to medium term
● Can be found as easily as coal ● No sulphur dioxide (SO2) is produced ● Gas-fired power stations are flexible in meeting demand and have a quicker start-up time than nuclear, coal and oil-fired reactors. |
● Burning produces carbon dioxide (CO2) although it produces less than coal and oil per unit of energy (CO2 contributes to global warming and climate change
● Expensive pipelines and networks are often required to transport it to the point of use. |
| Coal | ● Relatively cheap and easy to obtain
● Coal-fired power stations are flexible in meeting demand and have a quicker start-up times than their nuclear equivalents ● Estimates suggest that there may be over a century’s worth of coal left |
● Burning produces CO2 and SO2
● Produces more CO2 per unit of energy than oil or gas does ● SO2 causes acid rain unless the sulfur is removed before burning or the SO2 is removed from the waste gases. Both of these add to the cost of electricity |
| Oil | ● Enough oil left for the short term to medium term
● Relatively easy to find, though the price is variable ● Oil-fired power stations are flexible in meeting demand and have a quicker start-up time than both nuclear-powered and coal-fired reactors |
● Burning produces CO2 and SO2
● Produces more CO2 than gas per unit of energy ● Often carried between continents on tankers leading to the risk of spillage and pollution
|
| Nuclear | ● Cost of fuel is relatively low
● Nuclear power stations are flexible in meeting demand ● No CO2 or SO2 produced |
● Although there is very little escape of radioactive material in normal use, radioactive waste can stay dangerously radioactive for thousands of years and safe storage is expensive
● Building and decommissioning is costly ● Longest comparative start-up time |
Summary of Non-renewable resources
| Advantages | Disadvantages |
| ● Produce huge amounts of energy
● Reliable ● Flexible in meeting demand ● Do not take up much space (relatively) |
● Pollute the environment
● Cause global warming and acid rain (fossil fuels only) ● Will eventually run out ● Fuels often have be transported over long distances |
These renewable energy sources use modern technology to provide a clean, safe alternative source of energy:
| Source | Advantages | Disadvantages |
| Wind | ● No fuel and little maintenance required
● No pollutant gases produced ● Once built, wind turbines provide ‘free’ energy when the wind is blowing. ● Can be built offshore |
● Need a lot to produce a sizeable amount of electricity, which means noise and visual pollution
● Electricity output depends on the wind ● Not very flexible in meeting demand ● Capital outlay can be high to build turbines
|
| Tidal and wave | ● No fuel required
● No pollutant gases produced ● Once built, installations provide ‘free energy ● Barrage water can be released when demand for electricity is high |
● Tidal barrages across estuaries are unsightly, a hazard to shipping, and destroy the habitats of wading birds, etc.
● Daily variations of tides and waves affect output ● High initial capital outlay to build barrages |
| Hydro-electric | ● No fuel required unless storing energy to meet future demand
● Fast start-up time to meet growing demand ● Produces a lot of clean, reliable electricity ● No pollutant gases produced ● Water can be pumped back up to the reservoir when demand for electricity is low, e.g. in the night |
● Location is critical and often involves damming upland valleys, which means flooding farms, forests and natural habitats
● To achieve a net output (aside from pumping) there must be adequate rainfall in the region where the reservoir is ● Very high initial capital outlay (though worth the investment in the end)
|
| Solar | ● Ideal for producing electricity in remote locations
● Excellent energy source for small amounts ● Produces free, clean electricity0 ● No pollutant gases produced |
● Dependant on the intensity of light
● High cost per unit of electricity produced, compared to all other sources except non-chargeable batteries
|
| Bio-fuels | ● Contain no sulphur (responsible for acid rain)
● Can use many readily available waste materials ● Could be considered carbon neutral |
● Have lower energy output than traditional fuels
● Could lead to competition of land use between fuel and food |
| Geo-thermal | ● Minimal fuel costs
● Long life span and varying size of power output
|
● High initial capital costs
● Possible environmental damage from harmful gases escaping from deep within the Earth |
Summary of renewable resources:
| Advantages | Disadvantages |
| ● No fuel costs during operation
● Generally no chemical pollution ● Often low maintenance |
● Some produce small amounts of electricity
● Can be unreliable ● High initial capital outlay for most |
To ensure a security of electricity supply nationally, we need a mix of energy sources.