Currently, our planet gets most of its power from coal, oil and gas. These so-called fossil fuels were formed from the remains of living organisms existing millions of years ago, and when burned, release heat energy that can be turned into electricity. However, they are also very harmful to the environment, as burning fossil fuels also gives off a lot of carbon dioxide, a greenhouse gas that contributes to global warming.
As the Sun’s energy beats down on Earth, approximately 70 per cent of it gets absorbed by the land and oceans, while 30 per cent is reflected back into space. However, the 70 per cent absorbed by Earth is eventually radiated back out into the atmosphere in the form of infrared energy. Greenhouse gases then absorb this energy, but also emit heat in the process, which warms the Earth’s surface and lower atmosphere. This process occurs naturally and is what keeps the planet warm enough for living things to survive on it. However, a dramatic increase in greenhouse gas emissions since the Industrial Revolution has also caused a big rise in the average surface temperature of the Earth. This in turn has caused the world’s glaciers and ice shelves to melt faster, which will lead to a rise in sea levels resulting in the flooding of low-lying areas of coast. An increase in global temperatures fuels more fierce and devastating tropical storms and hurricanes, and could also trigger severe droughts in some parts of the world.
Even if burning fossils didn’t have this destructive power, it would still be important for us to find alternative sources of energy. Although fossil fuels are technically renewable, as they are made from living organisms, that fact we are using them up at a much faster rate than they can be formed means we will eventually run out.
Some renewable sources of energy, such as solar, wind and hydroelectric power, are already being used, but these come with their own problems that prevent them from replacing fossil fuels altogether. However, as we continue to find innovative new ways to harness unused energy, our planet could soon become a green, self-powered machine.
The limitations of green energy
Despite the infinite supply of energy available to us from renewable sources, we still rely heavily on fossil fuels. Unfortunately, there are many issues that still need to be overcome before we can become completely green.
One of the main obstacles is cost, as the infrastructure required for most renewable energy sources is expensive, especially when compared to that of fossil fuels. Solar panels, wind turbines, hydroelectric dams, tidal barrages and nuclear fusion plants are all expensive to build and storing any excess energy they produce can also be costly.
The reliance on unpredictable weather is another major issue for some forms of renewable energy. Wind, for example, is very inconsistent, and of course solar energy is only harvested in significant amounts during clear daylight hours. Therefore, fossil fuel energy is still required as a back-up when the conditions aren’t quite right.
At the moment, technology used to harvest renewable energy is also not particularly efficient. Vast areas of land or sea need to be covered with solar panels or wind turbines in order to generate the same amount of power produced by non-renewable sources. This can generate opposition from local residents, as some people believe wind farms spoil the countryside. Local ecosystems can also be negatively affected by some renewable energy sources. For example, hydroelectric dams disturb the flow of rivers, disrupting native wildlife and local settlements, and tidal barrages can be harmful to marine life.
Of course, some sustainable solutions are severely restricted by location anyway. For example, geothermal energy can only be produced near areas of volcanic activity, and tidal energy requires strong tides.
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