As constant pollution and the looming effects of climate change make it increasingly urgent to phase out fossil fuels, we are turning to renewable energy to replace our current sources. As of 2019, 17% of U.S. power generation comes from renewable energy, a combination of various types including wind, hydroelectricity, solar, and geothermal. Now that plans are being made to invest in and increase usage of renewable energy, many people ask which source is the best. Which is the cheapest, the most efficient, the most environmentally friendly? However, there is not a clear answer to this question, as each renewable has its own unique pros and cons and may be better in some areas than others.
Wind power has many advantages. Not only does it produce energy without any emissions, it is also one of the cheapest forms of energy to choose from. This is because of the lack of highly expensive materials, the little maintenance needed on turbines once they are built, as well as their long lifespan of several decades. Additionally, while a single turbine is very tall, it does not take up much ground space. Sadly, everything comes with drawbacks: for wind energy one of those is an impact on local wildlife. Wind farms take or alter habitat and cause bird and bat mortality. However, according to the Department of Energy, estimated annual bird mortality rates associated with wind turbines are ten times less than those with communications and other towers, one thousand times less than with power lines, and one thousand to ten thousand times less than with buildings. An additional downside is that wind farms are often far from big cities that require the most power, resulting in long transmission lines to transport the power produced. Among the drawbacks, wind turbines cause aesthetic and noise pollution, as they are often built in beautiful rural locations and can disturb humans and wildlife with their ever rotating blades.
While hydroelectric dams are expensive to build and emissions are produced during this process, once built this cost and pollution is offset by their long life-span of clean energy production. They also provide flood control and water for consumption or irrigation. Hydroelectricity is also highly flexible, as energy production can be quickly started and stopped, making hydroelectricity capable of responding to fluctuations in energy consumption. It is also dependable, as it produces consistent levels of energy unlike other renewable sources that are intermittent (such as wind or solar). However, dams and reservoirs take up a large amount of space. They contribute to habitat loss or modification, notably for migrating fish, and can displace communities that live near the river being dammed. The physical characteristics of the water near them is also affected from changes in temperature patterns to excessive sediment deposition. Due to these negative aspects of dams, many have been removed to restore the river and surrounding area to their natural state. Over 1,700 dams have been removed in the U.S., most occurring after 1990, when dam removal began increasing greatly.
Geothermal power involves harnessing natural heat from below the surface of the earth that is found in reservoirs of hot water and steam. One considerable advantage of this energy source is its consistency. Geothermal power plants can produce the same amount of energy at any time of day or year, meaning power output can be accurately predicted. Other renewables like solar and wind do not have this luxury. Geothermal also has a small land footprint, using less land per GWh of energy than many energy sources including coal, wind, and solar. Despite these advantages, producing geothermal energy has several disadvantages. Power plants can only be built at locations that have underground reservoirs of hot water or steam which mostly occur in volcanically and tectonically active regions. Additionally, the drilling process used to access the geothermal reservoirs can cause surface instability which leads to a risk of earthquakes. Although it is clean compared to fossil fuels, there are small levels of emissions associated with certain geothermal power plants, as they release gases stored beneath the surface of the earth including greenhouse gases and hydrogen sulfide..
There is a lot of potential for solar energy as enough sunlight hits the planet each day to supply energy for the entire world for a year. Once solar farms are installed they have no emissions and require little maintenance. Another type of solar energy production, photovoltaic (PV) cells, can be installed on rooftops, which increases the value of a property, saves money on electricity bills, and lessens the environmental impact of the building. These PV cells are becoming increasingly popular for household energy, especially in southwestern states, but hazardous materials are used in their production. Another impact of solar on the environment is habitat loss and modification since solar thermal plants require lots of space and the power must be transported to consumers. Other downsides include harm to migratory birds, water consumption, potential leaks of hazardous fluids, and the fact that output depends on good weather.
So, which renewable energy source is the best?
As you’ve seen from this article, it is difficult to choose one superior renewable resource, since they each have distinct pros and cons. Depending on what you are prioritizing, different sources will be better than others. Some are cheaper like wind, while some are more consistent and dependable like hydroelectric and geothermal. Some take up less habitat or do less harm to local wildlife and others consume a lower amount of water. Each performs best under different conditions, like solar in the southwest where it is sunny, and wind in the northeast where it is windy.
With all of this in mind, the best way to phase out fossil fuels is likely using a combination of the various renewable resources we have instead of choosing one. Using each where they are the most effective and utilizing the different advantages to complement the others. To learn more about these energy sources including descriptions of how they work, where they are used, and new developments in the industries, please watch our Happy Hour on renewable energy.