A renewable energy project aims to generate energy in a sustainable manner by avoiding the use of finite natural resources like fossil fuels. Nuclear power is not considered environmentally friendly because it relies on the extraction of non-renewable uranium deposits. Renewable energy projects employ a wide range of energy sources, which can be classified into four categories: light, heat, kinetic energy, and chemical energy. Solar and geothermal energy are examples of light as an energy source; hydroelectric power, wind, wave, and tidal power are examples of kinetic energy, or the energy of motion; and biomass and biofuel energy are examples of chemical energy, or the energy locked in chemical compounds that can be released by combustion.
Although heat can be used to heat buildings directly, a renewable energy project’s primary goal is to generate electricity. Solar energy can generate electricity through the photoelectric effect, in which certain substances produce an electric current when exposed to light, but most electricity is generated through turbines that are powered by steam generated from natural sources of heat or directly by kinetic energy sources. As an alternative to fossil fuels, biofuels could be used directly to power vehicles.
Concerns about nonrenewable energy sources being depleted have prompted widespread implementation of renewable energy projects. Concerns about climate change, pollution, and nuclear power plant safety have all contributed to the search for renewable energy. Finding efficient and cost-effective ways to exploit renewable energy sources has sparked a lot of research.
Solar energy can be used in two different ways. Photovoltaic cells, also known as solar cells, convert light directly into electricity and can be grouped together to create large solar panels that generate a lot of energy. These can be used to provide electricity to homes on a small scale or in large arrays for large-scale electricity production.
Using mirrors to focus the sun’s energy onto a target is another way to harness solar power. This produces heat, which can be used to power a power plant that produces steam to power a turbine or uses the expansion of heated gas to power a piston. Alternatively, on a smaller scale, the heat can be used to heat water or cook directly.
Geothermal energy is a renewable energy source that uses heat from the Earth’s core as an energy source. It is considered renewable because it will not run out for billions of years. Alternative energy projects could take advantage of geothermal energy by using natural hot water near the surface to heat buildings or pumping water deep underground to heat sources and convert it to steam to power turbines.
Large-scale hydroelectric projects use the gravity-powered flow of water to drive turbines, allowing them to tap into the potential energy of elevated bodies of water. Most hydroelectric schemes have involved the construction of dams and the flooding of land areas, and they require suitable terrain and significant amounts of surface water. Smaller-scale projects involving river running water have also been carried out.
Wind turbines are used to capture wind energy. Three blades are mounted on a metal column in most cases. The blades turn, which turns a turbine, which generates electricity. Wind turbines can be installed singly to provide energy for buildings, but they must be installed in large numbers for large-scale electricity production, resulting in “wind farms” that cover large areas of land.
Wave and tidal power projects use the movement of ocean water to generate electricity as a renewable energy source. Wave power generators rely on converting wave motion into rotational motion to generate electricity. Shore-based plants that use incoming waves to force air through a chamber into a turbine, or offshore structures that capture the kinetic energy of waves and use it to pump fluid to an onshore plant, could accomplish this. There are a variety of designs available, including long, flexible tubes that float on the surface and hinged barriers that move back and forth.
A barrage that acts as a dam across a tidal river estuary can be used to capture tidal energy. To power turbines, water from incoming or outgoing tides is forced through tunnels. Despite their significant energy-generating potential, tidal barrages generate electricity only when the tides are flowing, potentially disrupting delicate estuarine ecosystems.
Chemical energy locked in organic materials is used in a biomass renewable energy project. These projects could burn agricultural waste directly or use biomass to make alternative fuels like ethanol from sugar cane fermentation or methane from sewage and animal waste. Despite the fact that these resources are renewable, biofuels produce carbon dioxide in the same way that fossil fuels do, so many people believe they contribute to climate change.