There are four major types of renewable energy: energy from the sun, from the wind, from water, and from the earth itself. These materials are not only good for the environment, but they also emit less pollution than fossil fuels like oil and coal.
On the other hand, fossil fuels are natural materials that took hundreds of millions of years to form and can't be made again. They are a big cause of climate change, so we need to switch to renewable energy sources to save the world.
Solar power makes electricity by using the energy from the sun. This is done with photovoltaic (PV) cells, which turn the energy in sunlight into energy that can power small electronics or homes and buildings.
These PV cells are set up in panels so that they can gather energy from large areas of sunlight. Most of the time, they are used in big solar power plants, but they can also be put on top of houses and other buildings.
Whether they are used to make heat or electricity, solar technologies provide an endless supply of free, renewable, clean, and "green" energy that could possibly meet all of the world's energy needs in the future.
Photovoltaics and concentrated solar power (CSP) are the two main types of solar technology. Concentrating solar power is bigger than PV used in homes or businesses. It uses lenses or mirrors to focus sunlight into a narrow beam that heats a fluid to make steam, which then turns an engine to make electricity.
Hydropower is a type of green energy that makes electricity by using water. It is a fairly cheap way to make electricity, especially for smaller towns.
Most hydropower plants are on or near bodies of water, like rivers, lakes, or waterfalls. How much power a plant can make depends on how much water flows through it and how much the elevation changes from one point to another. This is also called "head."
There are several kinds of hydropower plants, such as dams, run-of-river plants, and pumped storage plants. Pumped-storage hydropower saves energy by pumping water uphill from a lower pool to an upper reservoir and then releasing it back into the river when demand is high.
Hydropower can do more than just make electricity. It can also help cut down on greenhouse gas emissions. It is a clean, renewable energy source that doesn't use fossil fuels and cuts down on smog. It is one of the most common ways to get power on Earth.
Biomass is a natural, renewable resource that has been used to heat houses and cook food for hundreds of years. It is also the main way that some power plants get their energy.
Biomass energy can come from wood, plant remains and grasses, forestry waste, oil-rich algae, and the byproducts of other businesses, such as waste gases, landfill gas, or animal waste.
It is a type of energy that doesn't produce carbon dioxide and can be turned into power, heat, and fuel for cars. It can help cut down on greenhouse gas emissions and is a good way to reach the 20% renewable energy goal set by the Paris climate deal.
Old-growth woods, which are known to store more carbon than new-growth forests, can also be used to grow biomass. But this can only happen if the trees are cut down, replaced, and given time to grow before they are burned as fuel.
Hydrogen is a flexible fuel that can be made, kept, and moved in a lot of different ways. It can be used to power homes and businesses, as fuel for cars, trucks, and ships, or to store green energy that isn't used right away.
Methane and high-temperature steam combine with a catalyst in a process called steam methane reforming (SMR). This creates hydrogen. This makes hydrogen gray.
Then, a method called electrolysis is used to use electricity to separate water into hydrogen and oxygen. This is used in fuel cells or tools for refueling, and electric cars are starting to use it more and more.
The cost of making hydrogen from energy with low carbon emissions is going down. This makes it cheaper to make hydrogen from green sources. But over the next 30 years, it will need to grow by three orders of magnitude to compete with standard fossil fuels.
