The United States is the second biggest energy consumer in the world, second only to China. Much of the U.S.’s energy is produced by nonrenewable sources, which will run out or will not be replenished in our lifetimes.
In 2021, nonrenewable energy sources, such as petroleum, natural gas, and coal, comprised nearly 78% of America’s energy production. Nonrenewable energy sources are not only in danger of depleting, but producing these resources also causes severe environmental impacts, such as air and water pollution, often making the land they were drilled or mined from unusable for future use.
Recently, the United States has begun to rely less on coal to produce its energy. Overall, sources of renewable energy, such as wind and solar, only make up around 12% of the country’s energy production, but renewable energy sources are becoming more widely adopted in commercial businesses and homes.
There are more renewable energy sources than just wind and solar, and many yield positive environmental impacts. Read on to learn about the different types of renewable energy sources and how they may eventually replace our dependence on nonrenewable sources.
What is Renewable Energy?
Renewable energy comes from natural resources that are replaced at a higher rate than they are consumed. One example is sunlight, from which solar panels can harvest the sun’s power and convert it into usable energy that powers our homes and businesses.
Wind is another example of renewable energy that is constantly being replenished. While solar and wind are two of the most common renewable energy sources, others are gaining popularity as alternatives to nonrenewable resources. Below are the various types of renewable energy sources.
Solar energy is the most common renewable energy source, and you’ve probably noticed more and more solar panels in businesses and homes than in years before. Because the sun gives off more energy than we need to power nearly everything on earth, solar is the most abundant renewable energy source, and many countries are investing heavily in infrastructure to capture it.
Solar power has several benefits over nonrenewable energy. With solar, no greenhouse gas emissions are released into the atmosphere when solar panels create electricity. Greenhouse gases cause increased temperatures by trapping heat and contribute to respiratory diseases by increasing air pollution and creating smog-like conditions.
Once solar panels are installed, additional fuel sources aren’t required, meaning solar power can create large amounts of electricity without the uncertainty and expense of securing extra fuel supplies, such as coal or natural gas.
The main drawback to solar as a renewable energy source is that solar panels won’t generate as much power during cloudy or smoggy days, nor will they create any power at night. However, solar energy can be stored in batteries to be used during the night and other times when less power is produced.
In addition, in systems set up for net metering, any additional electricity that is produced during the day is sent back to the power grid. When you need more electricity than your solar panels produce, such as during the night or on cloudy days, the electricity is sent back from the grid. Plus, advancement in solar technology has driven the cost of solar panels down, making it one of the most affordable renewable energy sources.
Wind energy is another type of renewable energy source and one that many cities and countries worldwide are starting to invest in. Harnessing wind power is nothing new; in fact, people have used wind energy basics to power mills and ships for centuries. However, wind farms are more recent developments and work by using the wind’s kinetic energy to power turbines that generate electricity. These turbines are typically installed in areas with open plains, near water, and in mountain gaps that can funnel and intensify wind. Wind energy technologies have improved significantly over the last several years to maximize electricity production.
Unlike solar, wind energy output isn’t as predictable because average wind speeds vary significantly by location. Still, the energy harnessed from wind exceeds global electricity production, making this a viable renewable energy source, especially if wind energy production is coupled with other renewable efforts, like solar energy farms.
There has been pushback on wind farms obstructing views or creating noise pollution, especially near residential areas. However, the best locations for generating wind power are often away from cities, such as offshore, which can provide tremendous potential for wind power.
Like wind energy, hydropower is a renewable energy source that has been used for centuries. Past civilizations have used water wheels to pump water, forge metal, grind grain, and cut timber.
Hydropower works by moving water from higher to lower elevations and harnessing the kinetic energy of falling water. Today, large-scale hydropower operations are constructed near reservoirs and rivers.
One of the most famous examples of hydropower is the Niagara Falls Hydropower Plant, which produces close to 4.9 million kilowatts—enough to power nearly 4 million homes. Reservoir hydropower plants rely on stored reservoir water and release it over turbines to generate electricity. River hydropower plants harness energy from flowing rivers, which consistently turn turbines to generate power.
There are drawbacks to hydropower as a reliable renewable energy source. Reservoirs generally rely on stable rainfall patterns, which can be negatively impacted by droughts or changes to the ecosystem. The same issues can also affect rivers. If a river’s depth falls below a certain level, it won’t adequately turn the hydropower turbines efficiently. Moreover, the infrastructure needed to create a hydropower plant can negatively impact ecosystems. Hydropower plants can alter the natural landscape and change the concentration of nutrients and water temperature, which can affect wildlife in the area.
Geothermal is another type of renewable energy source that utilizes the earth’s internal thermal energy. All geothermal power plants use steam to turn large turbines which power electrical generators. There are three types of geothermal power plants:
- Direct Dry Steam: The oldest type of geothermal plant, direct dry steam plants send steam directly over a turbine, which drives an electric-producing generator.
- Flash and Double-Flash Cycle: In this type of geothermal power system, hot fluids (of at least 360 °F) are sprayed into a tank held at a lower pressure than the fluid. This causes much of the liquid to vaporize rapidly (or “flash”), which turns a turbine that powers the generator.
- Binary Cycle: Hot water extracted from the earth’s interior and a secondary fluid with a lower boiling point than water pass through a heat exchanger. Similar to a double-flash cycle, heat from the geothermal fluid causes the secondary fluid to turn quickly into vapor, which then drives a turbine.
Geothermal power is considered an environmentally friendly renewable energy source because most plants have a low carbon footprint, especially compared to plants that use fossil fuels. Plus, geothermal energy is naturally occurring, so no additional fuel source is needed to power the turbines.
However, there are some downsides to geothermal power as a renewable energy source. For these plants to be sustainable, the fluids used to power these systems need to be pumped back into the reservoir before it’s depleted. Moreover, geothermal power plants are expensive, costing millions of dollars to develop. In some cases, these plants have caused earthquakes in regions that otherwise did not experience them, due to the pressure they put on the earth’s interior.
Biofuel energy is a renewable energy source produced from various organic matter or biomass, such as wood, plants, charcoal, and manure. You’re creating bioenergy when you burn wood for a campfire or light charcoal briquettes to heat a grill.
While energy created by burning biofuels produces greenhouse gas emissions, they are significantly lower than when burning fossil fuels. However, relying on biofuels as a renewable energy source has several drawbacks. Wood and manure as biofuel sources typically lead to large-scale deforestation, negatively impacting the environment. While biofuel energy is cleaner than energy produced by fossil fuels, it’s not as reliable as the different types of renewable energy sources mentioned above.
Renewable Energy Powering Our Future
While fossil fuels still power most of the country, several types of renewable energy sources are replacing these nonrenewable ones.