Renewable and non-renewable energy resources![]() Renewable energy sourcesThese are being constantly replenished by natural systems in a short enough time scale that we will never run out of them. The symbol on the right is the universal 'recycling symbol combined with a graphic for the green earth from http://wxresearch.org/ - it wonderfully illustrates what using renewable energy does. Renewable energy resources are the oldest, cleanest and in most cases the most efficient forms of energy humans have at their disposal. They will never run out (well not until our Sun burns out - and we will probably be extinct by then!) and do not pollute the environment by emitting gases that cause global warming effects or acid rain, nor do they produce radioactive waste. Non-renewable energy sourcesThese will run out eventually because they are not being replaced naturally at a fast enough rate for us to make use of them. Non-renewable resources are widely used directly (as heat sources) or to make electricity. Nuclear power uses Uranium. This was in the rocks of the planet when it was formed - we cannot get any from anywhere else! The nuclear industry has tried to put forward the case that it is renewable as the process that splits the Uranium 235 to make nuclear (or atomic) power also causes the Uranium-238 present to change into Plutonium and that can be used as a nuclear fuel too. But nuclear power is not classed as renewable - it is a non-renewable source. You might argue that fossil fuels will be replaced! They are the fossilized remains of plants and animals, so living things today could form new fossil fuels. That is true... but to be a fossil you must be more than 10,000 years old ... so even a leaf would take that long to turn into pure carbonized fossil material - a whole tree (needed for a decent coal seam) would take a lot longer! The important thing here is to understand the timescale involved. 7,000 years ago Europe was in the Stone age and the earliest pyramids were thought to be built about 5.000 years ago... so does that put it into perspective for you?
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