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Fossil fuels currently dominate the world energy supply and will most probably continue to do so over the next 25 years. The International Energy Agency predicts that oil, natural gas and coal will meet 81% of the world’s primary energy demand by 2030. That’s 1% more than in 2003 (see graphic).
However, renewable energies, such as solar or wind energy will expand at a very fast rate to meet the increasing power demands of the world’s population.
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 Biomass from the forests |
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If we could use the energy from the sun more intelligently then we might not contribute so much to the production of greenhouse gases and particularly carbon dioxide.
Trees absorb carbon dioxide from the atmosphere during photosynthesis and fix this in the wood of the tree.
If wood is burned this carbon dioxide is released.
So through planting and burning sustainable forests a carbon neutral source of energy can be produced.
That is to say, as much carbon is captured as is released on burning. But the wide scale use of sustainable forests as fuels is likely to be limited because demand for energy will most probably be much greater than the planting of such forests could support.
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| Wind and wave power |
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Energy from the sun does more than simply heat the earth, it provides the driving force for the winds and waves. Energy derived from wind or wave is carbon neutral - it neither adds nor takes away carbon dioxide from the atmosphere.
So, many people think that the future lies in extracting clean energy from these sources. Unfortunately, however, wind and wave power has the problem that it cannot be used on demand. There are times when the sea is still or the wind stops blowing so, unless energy can be stored at off peak times in a pumped storage system, then these sources can only be used to support other energy sources but may go a long way to replacing some of the reliance upon fossil fuels.
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| Carbon capture and storage |
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Capturing and storing carbon dioxide could play an important role in reducing emissions from coal-fired power plants.
The idea is to capture carbon dioxide from coal-fired power plants, compress it to a liquid and permanently store it deep underground. Suitable storage sites are natural rock formations thousands of metres below the surface, which are similar to natural oil and gas reservoirs.
It is believed that storing the carbon dioxide from 800 coal-fired power stations would reduce carbon emissions by the same amount as increasing wind power by 50-fold (Institute of Physics, UK, 2006).
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Vattenfall is constructing a pilot plant in Germany as part of their Carbon Capture and Storage (CCS) project. The pilot plant creates the opportunity to explore technology previously only tested in the laboratory.
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| Hydrogen power |
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Hydrogen is obtained by breaking down the water and by extracting the carbon atoms from the hydrogen atoms in fossil fuels such as natural gas.
Although we can reduce our emissions by using hydrogen power, it cannot completely remove fossil fuels.
Hydrogen contains very high levels of energy but it is not very dense. If we wanted to run a car with hydrogen, we would need to replace our 40-litre tank with a 126,000 litre one. The comparison is more favourable when for liquefied hydrogen – you would only need a 160 litre tank.
Hydrogen fuel cells convert hydrogen and oxygen into water. This process is known as electrolysis and produces electricity and heat. Hydrogen fuel cells have the advantage that they are extremely efficient. They can also be produced in any size, so you would be able to have one in a mobile phone for example.
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| Feeling inspired? Why not enter the Combat Climate Change competition? Follow the link to take up the challenge... more |
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 | Are there any other natural alternative sources that we could use to create carbon free energy? |
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| What are the advantages and disadvantages of using forests / wind / wave power? |
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| Which would be a better solution: to create a new clean form of energy, or encourage people to cut down on their energy use? |
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