There are a variety of energy sources that can be classified as renewable, including solar, wind, hydro, geothermal, and biofuels. Each source has its own advantages and challenges.
In addition to being environmentally friendly, renewable energy has also been a major contributor to job growth. In fact, it employs three times as many people as fossil fuel technologies do.
1. Wind
Wind is a natural energy source that is generated by the rotation of the earth and heat from the sun. It is used for a variety of purposes including pumping water, milling grain, and powering steam engines.
It can also be harnessed to generate electricity through wind turbines that stand together on a wind farm. Once the turbines are producing electricity, it can be sent onto the main power grid where it will be delivered where it is needed.
Wind energy is an extremely clean and abundant resource. It does not cause pollution like other sources of renewable energy do, and it helps to reduce the amount of greenhouse gas emissions that we release into the atmosphere.
2. Solar
Solar energy is the radiant light and heat from the sun that can be harnessed through a variety of technologies. These include photovoltaics, solar heating & cooling, and concentrated solar power (CSPP).
In terms of solar technologies for homes, the most common is solar photovoltaics that convert sunlight directly into electricity to run appliances and fans. These technologies can also be used for solar water heating to supply hot water and swimming pools during the winter.
In addition to the residential application, large solar power plants can be built to provide electricity on a utility scale to power cities and small towns. These systems use photovoltaics and concentrating solar power technologies to produce energy in a way similar to traditional power plants, but can store the power they generate for later distribution.
3. Hydro
Hydro energy is a renewable energy source that harnesses the power of moving water to produce electricity. It is most commonly associated with dams, but can also be used to generate electricity from run-of-river and tidal projects.
Hydro power plants use turbines to convert the kinetic energy stored in water flow into mechanical energy, which is then converted to electricity by generators. Electricity is then fed into the grid.
Hydropower is an ideal complement to variable renewables like wind and solar because it offers a steady supply of clean, cheap energy that can be turned up or down in response to weather conditions and seasonal fluctuations. This helps to avoid the negative impacts of variable renewables such as outages and peaks in demand.
4. Tidal
Tidal energy is a renewable, predictable source of energy that is much more efficient than wind and solar. It is also a clean and sustainable resource that doesn’t use fossil fuels or other polluting resources.
Tidal power is a potential solution to the growing need for more reliable, low-cost energy production. However, the industry is still in its infancy.
Despite some promising technological advances, tidal power remains limited by a few major barriers, including cost and environmental impacts.
The current technology used to harvest tidal energy is known as tidal barrages, in which tidal water is held back behind a barrier to create a difference in water levels on both sides of the barrier to generate electricity. Currently, there are only a few commercial-scale tidal barrages in operation around the world.
5. Geothermal
Geothermal energy is a renewable form of power generated by extracting the heat that is naturally produced inside the Earth. It can be used to provide electricity, heating and cooling, and even to help with water treatment.
There are many different types of geothermal plants. They all use the same basic process of tapping underground reservoirs of hot water and steam to generate electricity.
The most common type is called a flash steam plant, which uses a high-pressure system to pull steam from underground geothermal reservoirs. The water is pumped into a tank at a pressure lower than it is under ground, and some of it “flashes” or evaporates rapidly into steam to turn a turbine that produces electricity.
