Renewables are part of the planet’s physical makeup, and so they can’t be depleted. We’re talking about wind, sun, water, biological matter and the heat far below the Earth’s surface. Each offers sustainable energy possibilities with vastly reduced carbon dioxide emissions compared to “traditional” sources like fossil fuels—petroleum, coal and natural gas—and crude oil-based petroleum products.
"Today, approximately 11% of the total U.S. energy consumption comes from renewable energy sources."
Renewable energy is often called “alternative energy” because most of the energy currently consumed in the United States comes from “traditional” sources. Today, approximately 11% of the total U.S. energy consumption comes from renewable energy sources1. Knowing what we know about the current levels of pollution on Earth, isn’t it about time to take full advantage of the sustainable solutions around us?
Forget “walkin’ on sunshine” … in theory, we could all be living on sunshine, given the sheer volume and inexhaustible nature of the sun’s power. Yep—the amount of energy from sunlight that hits the earth in just one hour could supply the world’s energy needs for an entire year!
Solar energy uses that power and converts it into clean electricity for homes and businesses. In 2016, it was the fastest-growing source of new energy in the world. And as of 2018, between utility-scale solar power plants, commercial solar and residential solar, the U.S. has a total installed solar capacity of 55 gigawatts (GW)—enough to power nearly 11 million homes.
Thanks to improved technology, more affordable materials and increased customer demand, solar continues to become more affordable. For many homeowners, that means rooftop solar now makes economic sense and can provide long-term savings.
The answer to worldwide sustainable energy? It may indeed by blowin’ in the wind: in 2017, new installed wind capacity totaled 52.4 GW globally2, with 13% of it in the United States alone.
Capturing the natural energy of the wind produces wind power. Wind turbines—those tall, three-bladed towers you may have seen while driving through agricultural areas—convert that energy into electricity. Single wind turbines generate electricity for nearby homes, while larger wind turbines grouped together in wind farms can power several thousand homes. There are even offshore wind farms that take advantage of the strong, consistent winds of the coastlines.
As with solar energy, wind power has become more affordable in recent years with advancements in technology and increased demand for clean energy. Customers in areas with deregulated electricity markets can choose residential and commercial electricity plans that offer 100% wind energy.
Here’s a renewable energy source we don’t hear much about on a daily basis: geothermal energy. It’s one of the least-explored sources of renewable energy in the United States, but it has great potential. After all, it’s created using heat from the Earth’s core, which is hotter than the surface of the sun!
The word “geothermal” comes from the Greek words “geo” (meaning “Earth”) and “thermos” (meaning “heat”). The Earth’s heat is tapped by drilling deep into the Earth’s surface, capturing rising hot water and steam. That steam rises to the surface and pushes a turbine, which rotates a generator. The generator produces electricity, sends it to the power grid and—violà!—electricity. Geothermal energy can also be used to heat and cool buildings through geothermal heat pumps.
The U.S. leads the world in geothermal power generation. Seven states have geothermal power plants: California, Nevada, Utah, Hawaii, Oregon, Idaho and New Mexico. As of 2017, California and Nevada produce the lion’s share of the country’s geothermal electricity (73% and 21%, respectively).
With about 71% of the Earth’s surface covered by water, it’s no surprise that H2O has historically been the world’s most popular renewable energy source. Hydroelectricity—also known as “hydroelectric power,” or “hydro power” for short—is generated using the power of moving water in oceans and rivers. Every state in the U.S. uses hydropower for electricity, with 70% of Washington State’s electricity coming from this renewable energy source.
To create hydroelectric power, a dam blocks water from flowing naturally. Instead, it is directed first through a pipe to a turbine, then back out on the other side of the dam. The force of the water spins the turbines, rotating a generator that produces electricity.
Hydropower generation is about 90% efficient, compared to fossil fuel plants that generally run at around 60% efficiency. Thanks in large part to this efficiency, hydropower is one of the least expensive renewable energy sources in the nation.
If you’ve ever been near a campfire or fireplace, you’ve witnessed biomass energy through the burning of wood. “Biomass” is any organic matter—trees, plants, food waste, animal waste. Energy is released when biomass burns or decomposes. Since plants and food will continue to grow, and there’s no shortage of animal waste being produced, biomass is a renewable and sustainable source of energy.
How does biomass energy work? Plant-based biomass like wood scraps, sawdust and excess crops are burned to heat water and create steam. Animal-based waste from cows or other farm animals is collected in a large tank or pond with bacteria. As it decomposes, methane is released and burned to heat water, creating steam. In both cases, the steam spins a turbine to power a generator, which creates electricity and is sent to transmission lines.
And how’s this for turning lemons into lemonade: biomass energy not only offers a clean alternative to traditional energy; it also provides a way to divert products like excess crops, sewage sludge and the organic portion of trash from the waste stream.