The world’s energy needs are growing every year. As countries develop and their populations grow, the demand for the energy to support them increases. Until now, this growth has relied heavily on the use of fossil fuels (coal, oil, and gas). Although their use has been essential so far, reliance on them has led to pollution problems, and perhaps the greatest future challenge for mankind, climate change.
Thankfully, many countries are making the important change from fossil fuels to clean, green, and renewable sources of energy. Fossil fuels produce emissions, such as carbon dioxide, which contribute to the greenhouse effect and the global climate. They are also “finite” sources, which means there is a limited supply of them. Once a source has been used up, another must be found, and finding new sources becomes more difficult and expensive over time. With no emissions or waste, renewable energy sources cause limited damage to the environment. They are renewable because they can be naturally replaced and can therefore be consumed without the risk of using them up.
Here are the main types of renewable energy, with facts and examples from around the world.
Hydropower The power of water turns turbines which produce electricity. Since ancient times, watermills have been used for many things, from grinding wheat to sawing timber. Countries such as Paraguay and Norway already produce all or most of their energy from hydropower. Most of the renewable energy in China comes from hydropower plants, such as the Three Gorges Dam, the world’s largest power station.
Solar Solar panels turn heat from the sun’s rays into electricity, and solar heaters use that energy to heat water directly. This is the fastest growing renewable energy source, as the cost of the technology is falling. Germany has the highest solar capacity in the world, but China is the world’s largest market and the largest producer of solar technology.
Wind Tall turbines are turned by the wind to produce electricity. Wind “farms” are built on land, or offshore, to take advantage of more frequent and powerful winds at sea. The world’s largest wind farm is the London Array. It has 175 wind turbines and is 20 km off the coast of England. Researchers think China could meet all her electricity demands from wind by 2030. Wind farms in provinces such as Gansu have an endless wind supply.
Geothermal This has been a natural source of energy for thousands of years. Today, heat from below the earth’s surface heats water into steam that turns turbines to generate electricity. The USA has the largest capacity, with over 80% generated in California. The Yangbajing Power Plant is the largest geothermal plant in China.
Biofuel This is material from biological sources (such as corn or grain) or waste products that is used to produce energy. It is used in generators for electricity, or in cars and other machines. Brazil has produced and used biofuel made from sugar cane for 40 years. China is the world’s third largest producer of biofuel.
So, what are the pros and cons of renewable energy? The strongest “pro” is that it is clean, producing almost no pollution. Resources are abundant and free, and cannot be used up. Projects, once set up, require less to maintain. They are ideal on a small scale; one can have solar panels on the roof, but not a coal power station in the kitchen! It is also better for energy security. Getting resources from within the country means less reliance on resources from abroad, and less risk from political or economic changes.
There are also some “cons”. With no wind or sun, there may be no power. Projects are built in places where resources are abundant, but often far away from the cities where power is needed. Solar projects are expensive to set up. Hydroelectric projects can cause problems with flooding when they change the natural flow of rivers. Biofuel projects use up land, which could be used for growing food.
Can renewables really be the future of energy? Our modern world has been built on fossil fuels, so it is hard to change quickly. However, the use of renewable energy is growing in China and around the world. Given the problems of climate change, there is little doubt that they will continue to grow. As extracting fossil fuels is becoming more difficult and expensive, the cost of renewable energy is falling. New battery technology, for example, solves the problem of bringing electricity from distant sources to cities. Along with our being more aware of our energy consumption and waste, a clean, green energy future is possible and necessary.