Renewable Energy Resources Will Never Run Out
a) A renewable energy source is one that will never run out.
b) Most renewable energy resources damage the environment, but they will never run out.
c) Sadly, they don't all provide much energy and some of them are unreliable as they depend on the weather.
Hydroelectricity - Building Dams and Flooding Vall
1. Hydroelectric power usually involves flooding a valley by building a dam (a barrier constructed across a waterway to control the flow or raise the level of water).
<-- This is an image of a dam.
2. Rainwater is caught and then it's allowed out through turbines.
3. There is a big impact on the environment due to the flooding of the valley and possible loss of habitat for some species.
4. A big advantage is immediate response to increased electricity demand - more water can be let out through the turbines to generate more electricity.
5. Initial costs are often high but it's a reliable energy source.
Wave Power - Lots of Little Wave Powered Turbines
1. Waves can provide an up and down motion which can be used to drive a generator.
2. Wave power is fairly unreliable, since waves tend to die out when the wind drops.
3. The majority of electricity generated from wave power uses waves close to the shore. Waves further out in the ocean are much more powerful - offshore wave farm are now being developed to harness this power.
4. Wave power is never likely to provide evergy on a large scale buit it can be useful on small islands.
Tidal Barrages - Using the Sun and Moon's Gravity
1. Tidal barrages a big dams built across river estuaries (the part where the tide meets the river) with turbines in them.
2. As the tide comes in it fills up the estuary to a height of several metres. This water can then be allowed out through turbines at a controlled speed. It also drives the turbines on the way in.
3. Even though it can only be used in a few of the most suitable estuaries, tidal power is a reliable energy source that has the potential to generate a significant amount of energy.
Wind Power - Lots of Little Wind Turbines
1. Each wind turbine has its own generator inside it so the electricity is generated directly from the wind turning the blades, which turn the generator.
2. There isn't any pollution (apart from a little bit when they're manufactured).
3. But wind turbines do spoil the view and they can be very noisy, which is annoying for people living nearby.
4. They only work when it's windy, therefore it's not always possible to supply more electricity when there's extra demand.
Solar Cells Generate Electric Currents
1. Solar cells generate electricity on a small scale.
2. Solar power is often used in remote places where there aren't many other ways to generate electricity, and in sattelites.
3. In sunny countries solar power is a very reliable source of energy - but only in the daytime. Solar power can still produce good results without costing a lot of money.
Geothermal Energy - Heat from Underground
1. This is only possible in certain places where hot rocks lie quite near to the surface. The source of much of the heat is the slow decay of various radioactive elements, including uranium, deep inside the Earth.
2. Water is pumped in pipes down to the hot rocks and it returns as steam to drive a generator.
3. This is actually brilliant 'free' energy with no real environmental problems.
4. The only big drawbacks are the high setup cost and the fact that there are very few places where this seems to be an economic option.
Biomass Is Natural Waste
1. Biomass can be anything from farm waste, animal droppings and landfill rubbish to specially grown forests.
2. The waste material is burnt in power stations to drive turbines and produce electricity. Or sometimes it's fermented (the chemical breakdown of a substance) to produce other fuels such as 'biogas' (usually methane) or ethanol.
3. The plants that grew to produce the waste (or to feed the animals that produced the dung) would have absorbed carbon dioxide from the atmosphere as they were growing. When the waste burnt this C02 is re-released into the atmosphere. So using biomass to generate has no overall effect on atmospheric C02 levels - so it's carbon neutral. (Although this only really works if you keep growing plants at the same rate you're burning things.)
Setting Up a Power Station
Because coal and oil are running out fast, many old coal- and oil-fired power stations are being taken out of use. They're often being replaced by gas-fired power stations because they're quick to set up, there's still a lot of gas left and gas doesn't pollute as badly as coal and oil.
When looking at the options for a new power station, there are several factors to consider:
- How much it costs to set up and run.
- How long it takes to build.
- How much power it can generate etc.
- Damage to the environment.
- Impact on local communities.
Getting permission to build certain types of power station can be a long-running process, and hence increase the overall set-up time.
Set-Up Costs / Set-Up Time / Reliability Issues
Set-Up Costs: Renewable resources often need bigger power stations than non-renewables for the same output. The bigger power station, the more expensive. Nuclear reactors and hydroelectric dams also need huge amounts of engineering to make them safe, which bumps the cost.
Set-Up Time: This is affected by the size of the power station, the complication of the engineering and also the planning issues (e.g. discussions over whether they should be allowed to build a nuclear power station on a stretch of beautiful coastline can last years). Gas is the one of the quickest to set up.
Reliability Issues: All the non-renewables are reliable energy providers (until they run out). Many of the renewable energy sources depend on the weather. With the exceptions of tidal and geothermal power (which don't depend on the weather).
Running/Fuel Costs / Location Issues
Running/Fuel Costs: Renewables usually have the lowest running costs, because there's no actual fuel involved (except biomass).
Location Issues: This is fairly common sense - a power station has to be near to the studd it runs on.
- Solar - pretty much anywhere though the sunnier the better.
- Gas - pretty much anywhere there's piped gas (most of the UK).
- Biomass - pretty much anywhere.
- Hydroelectric - hilly, rainy places with floodable valleys, e.g. the Lake District, Scottish Highlands.
- Wind - exposed, windy places like moors and coasts or out at sea.
- Oil - near the coast (oil transported by sea).
- Waves - on the coast.
- Coal - near coal mines, e.g. Yorkshire, Wales.
- Nuclear - away from people (in case of disaster).
- Tidal - big river estuares (the place where the tide of a river meets the stream).
- Geothermal - fairly limited, only in places where hot rocks are near the Earth's surface.
If there's a fuel involved, there'll be waste pollution and you'll be using up resources.
If it relies on the weather, it's often got to be in an exposed place where it sticks out like a sour thumb.
Atmospheric Pollution: Coal, Oil, Gas, Biomass (+ other's though less so).
Using Resources: Coal, Oil, Gas, Nuclear.
Visual Pollution: Coal, Oil, Gas, Nuclear, Tidal, Waves, Wind, Hydroelectric, Biomass.
Noise Pollution: Coal, Oil, Gas, Nuclear, Wind, Biomass
Other Problems: Nuclear (dangerous waste, explosions, contamination). Hydroelectric (dams bursting).
Disruption of Wildlife Habitats: Hydroelectric, Tidal