Renewable energy is the power we get from nature without using fossil fuels. It comes from natural resources like wind, solar, and water.
Unlike nonrenewable sources such as oil drilling, fracking, and coal power plants, renewables do not pollute the environment and are vital to tackling climate change.
Solar Energy
Solar energy is a renewable source of power that we use to power our homes, businesses, and vehicles. It’s a major player in the transition to a clean energy economy and is one of the most popular forms of alternative energy.
Unlike fossil fuels, which take millions of years to create, sunlight is a natural resource that replenishes itself at the rate we consume it. That means that it can be used again and again for generations.
To harness solar energy, we use photovoltaic panels or mirrors that concentrate the sun’s rays into electricity. This energy can be distributed to local power companies or pumped into the electric grid, depending on where you live.
The solar panels are made up of individual cells with layers of special semiconductor materials arranged in positive and negative layers (similar to the battery setup). Light energy hits these layers and frees electrons within the semiconductor material, creating direct current (DC) electricity. This is then captured by the wiring connected to these cells and converted into alternating current (AC) by an inverter.
Wind Energy
Wind energy is a clean and renewable source of electricity that can be used to power all kinds of things, from homes to businesses. One of the fastest-growing types of renewable energy, and it is becoming increasingly competitive with fossil fuels in terms of cost.
It is also a good source of energy for communities and can help reduce carbon emissions. It has fewer environmental impacts than other energy sources and can be integrated into existing communities without affecting land use.
The most visible parts of a wind turbine are its blades, which have propeller-like shapes and are mounted on a shaft inside a box called a nacelle. When the wind blows, it causes the blades to spin clockwise. This generates kinetic energy that triggers the main shaft to spin, and then a generator inside the nacelle converts it into electrical energy.
Hydroelectric Energy
Hydroelectric energy is a renewable form of power that harnesses the power of moving water. People have used this force for millennia to turn paddle wheels on rivers to grind grain and lumber and create electricity.
A hydroelectric plant uses a dam to store potential energy in a reservoir behind the dam and convert it into kinetic energy as the water flows downhill. The kinetic energy is then used to spin turbines and generate electricity.
The United States, hydroelectric plants can range from “micro-hydros” that power only a few homes to giant dams like Hoover Dam that supply millions of people with clean electricity.
In addition to producing energy, hydroelectric plants are a reliable source of “peak” or baseload power to provide electricity when demand is high. In the United States, hydropower supplies about half of our baseload capacity.
Geothermal Energy
Geothermal energy comes from heat that’s stored in the Earth’s interior. It can be used to generate electricity and even to heat buildings and water.
It’s available in many locations on Earth, and most of it can be harnessed with little environmental impact. Unlike other renewable energy sources, geothermal does not release carbon dioxide and other greenhouse gasses into the air.
Enhanced geothermal systems (EGS) can overcome some natural limitations by injecting fluid into hot rocks to reopen fractures and create pathways for the flow of hot water. This enables EGS to expand its use nationwide.
The most common way to use geothermal energy is in power plants. Flash steam plants take underground fluid reservoirs at temperatures higher than 182degC/360degF and pump them to a low-pressure tank at the Earth’s surface. Some of the fluid “flashes,” or evaporates rapidly into steam, and the steam drives a turbine that powers generators. Any liquid in the tank can be flashed again to extract more energy.