Many countries use nuclear power plants to produce energy — particularly in North America, Japan and Europe. Nuclear power plants use radioactive fuel to cause nuclear reactions which produce heat. The heat is used to boil water to create steam. This turns a turbine to make electricity. The benefit of nuclear power is that it does not release carbon dioxide or other harmful gases into the atmosphere.
However, the nuclear reactions do produce radioactive waste, which can be extremely dangerous. This waste lasts for thousands of years and must be stored in a safe place. People who work around radioactive waste must take precautions to ensure their health and safety and protect the environment.
Nuclear power plants are very costly to build and run, and fewer are being built around the world now.
Some countries use water to generate electricity. Huge dams are built in rivers and lakes, and the flow of water out of these dams is used to power great turbines which produce electricity.
Creating hydroelectricity does not release carbon dioxide or any harmful substances into the environment. However, building the dams can cause massive damage to river and lake systems. The flow of the river is disturbed and many animal homes are flooded or destroyed. People can also be affected — some dams being built in Asia will require many people to find new homes. There is a limit to how many rivers can be dammed.
Some new hydroelectric schemes do not cause flooding though, and can make a useful contribution to renewable energy production on a smaller scale.
Fuel cells can be used to produce clean energy using hydrogen. They work in a similar way to a battery – but they depend on a fuel supply such as gasoline, diesel fuel or natural gas. The fuel cell extracts hydrogen from this fuel source to produce electricity, as well as water and heat as by-products.
Fuel cells are a relatively clean form of energy production, particularly when compared to power generated from the burning of fossil fuels.
Fuel cells are currently in use and under observation at several demonstration sites. Scientists are working to determine the best fuel source and best technical components to use to make fuel cells more economical to make and operate. Right now, fuel cells may be too large and experimental to be used to help power electric cars and may be better suited for use in houses and in small commercial buildings.
The day may come when fuel cells become commonplace in houses, making it possible for homeowners to power their homes without having to be connected to the utility grid.
The energy of the sun can provide heat, light, hot water and electricity, and even cool your home.
Scientists know how to convert sunlight directly into electricity by using devices called photovoltaic cells. Small cells power watches and calculators, while large ones can create enough electricity for entire homes and businesses, and can even supply electricity to the electric grid of an entire town.
The sun can also heat water or air directly using solar heaters. Solar heaters can be installed in most homes and are a great way of providing heating and hot water using a renewable energy source. They can also be used to provide backup or auxiliary power in buildings.
Solar panels, also known as photovoltaic panels, can be costly to buy and install, but the long-term savings can help to reduce these costs.
In windy places, large windmills called wind turbines can capture the energy of the wind. Often lots of these turbines are built together on a ‘wind farm’ and used to create electricity. Smaller turbines can also provide electricity to individual homes or to small villages. Some wind turbines can also pump water or grind grain.
Wind turbines are often very tall. This is because wind speed increases with height – so taller towers allow turbines to capture more wind energy and generate more electricity. You can see these tall towers from a long distance, so care must be taken when planning where to build wind farms.
The movement of the ocean’s waves and tides through turbines can produce electricity in tidal power stations. However, building these systems can have a major impact on coastal environments.
Geothermal power stations use the natural heat from the Earth to produce electricity. Holes are drilled into the ground, and hot water is pumped to the surface, where it creates steam used to drive a turbine. Electricity can only be produced this way in specific places where the Earth’s crust has trapped hot water and steam underground.
At the moment, there are over 200 of these geothermal power stations in the United States – most of them in California and Nevada.
Biomass energy comes from organic material like plants and animals. One form is methane, the gas produced when material rots in a landfill. Methane can be collected and burned to produce energy.
Creating biomass energy is a good way to use up waste as fuel. Sugarcane waste, woodchips, seaweed and animal waste can all be used in this way. Other forms include fermenting sugarcane or woodchips to produce alcohol. The liquid can then be used as a fuel to run cars.