Clean and Renewable are just two of the many sustainability terms used when referring to energy substitutes for fossil fuels. At first glance it may seem like the two are mutual, you may have even read or heard them being used interchangeably. But when looking closely at the two, some differences emerge. So we had to ask: What’s the difference between clean and renewable energy?

Clean energy is the generation of energy that does not produce greenhouse gas emissions. Renewable energy is the generation of energy from sources that can be replenished naturally over time. The differences between the two have different implications for reducing global greenhouse gas emissions.

So, can energy be both clean and renewable? Why is some energy classified as clean but not renewable, and vice versa? And which specific energy sources are part of each? Keep reading to find the answers to all these questions as we’ll walk you through the differences between clean and renewable energy and why they matter.

How Are Clean Energy and Renewable Energy Defined

Generally speaking, both clean and renewable energy sources seek to preserve the Earth’s natural resources by offering an alternative to fossil fuels. These alternatives aim to reduce the effects of global warming by limiting greenhouse gas emissions. 

But there’s more to it.

What Does the Dictionary Say About Clean Energy and Renewable Energy

Although clean energy and renewable energy are often used to describe the same thing, they have slight differences in their definitions.

“Clean Energy: energy, as electricity or nuclear power, that does not pollute the atmosphere when used, as opposed to coal and oil”

Collins Dictionary

Clean energy is derived from processes that do not release greenhouse gas emissions into the atmosphere.

“Renewable Energy: energy that is produced using the sun, wind, etc., or from crops, rather than using fuels such as oil or coal | types of energy that can be replaced naturally such as energy produced from wind or water”

Cambridge Dictionary

Renewable energy is sustainable because the energy sources are in infinite supply, and we can keep harvesting them for years to come. 

We often use the terms “clean energy” and “renewable energy” interchangeably, but there are clear differences between these two. 

What Do These Differences Between Clean and Renewable Energy Mean

The subtle differences between clean and renewable energy may not seem significant, but their definitions have different implications on our environment:

• If energy is only clean but NOT renewable: the generation of energy does not produce greenhouse gases (or other pollution), but the energy source supply is finite. For example, nuclear energy generation is clean because it does not emit greenhouse gases. It is not renewable though because the material used to create the energy is limited.

• If energy is only renewable but NOT clean: the energy source is in infinite supply, but the process of generating the energy produces greenhouse gases. For example, hydropower is renewable because the water cycle is a perpetual process. It is not clean though because it produces greenhouse gas emissions.

To sum it up, clean energy means zero greenhouse gas emissions, but it isn’t always renewable. Renewable energy means the energy source is in infinite supply, but it isn’t always clean.

What Are the Differences and Similarities Between Clean Energy and Renewable Energy

The number one way to fight global climate change is to reduce greenhouse gas emissions. And clean and renewable energy can help cut down these emissions. But you know what’s even better than this? Energy sources that are both clean and renewable energy! 

Categorizing the above energy types as either clean, renewable, or both requires a detailed look into how the energy is produced and whether the source is unlimited or not. 

Which Energies are Both Clean Energy and Renewable Energy

If energy is both clean AND renewable, the generation of energy does not produce greenhouse gases, and the energy source is in infinite supply. Below are the energy sources that are both clean and renewable.

• Solar Energy: photovoltaic cells in solar panels absorb energy from sunlight, creating an electrical charge that moves in response to an internal electric field in the cell and creates electricity. This process is clean because no greenhouse gases are emitted during operation. It is also renewable because the sun will continue to emit energy until it goes supernova. 

• Wind Power: wind turns the blades of wind turbines around a rotor, which spins a generator to generate electricity. This process is clean because no greenhouse gases are emitted during its operation. It is also renewable because as long as the wind blows, wind power can be harnessed.

• Geothermal Energy: drilling down to hot water reservoirs creates steam that rotates a turbine, which spins a generator to generate electricity. This process is deemed clean because although it does release minute amounts of carbon dioxide, the amount is, well, minute. Geothermal is also renewable because the Earth has an almost unlimited supply of heat generated by its core, and the water extracted from the reservoirs can be recycled via re-injection into the ground. 

Solar, wind, and geothermal are all examples of both clean and renewable energy because their generation does not produce greenhouse gas emissions and their resource supply is infinite. 

Which Energies Are Only Clean Energy But Not Renewable Energy

If energy is only clean but NOT renewable, the generation of energy does not produce greenhouse gases, but the energy source supply is finite. Below are the energy sources that are clean but not renewable.

• Nuclear Energy: in nuclear fission, an enormous amount of energy is released when electromagnetic radiation is used to split the nucleus of a Uranium atom (U-235). Nuclear energy is clean because the process of splitting the nucleus of a U-235 atom does not produce greenhouse gas emissions. It is not renewable though because there is a finite supply of U-235 found on Earth.

Did you know that uranium can be found in trace amounts practically everywhere in the world? But nuclear power plants use the second most common isotope of Uranium (U-235) which has a relative abundance of only 0.7%. And most of the original U-235 on earth has already decayed because it has a half-life of about 700 million years.

Which Energies Are Only Renewable Energy But Not Clean Energy

If energy is only renewable but NOT clean, the energy source is in infinite supply, but the generation of energy produces greenhouse gases. Below are the energy sources that are renewable but not clean.

• Hydropower: Flowing water turns turbines, which spins a generator to generate electricity. This process is renewable because the water cycle is a continuous process that recharges itself. It is not clean though because hydropower produces greenhouse gas emissions, although the rate of emissions is much lower than that of fossil fuels. The construction of hydroelectric facilities and biomass decomposition in the reservoirs produces carbon dioxide and methane. 

• Biomass: Wood, agricultural crops, biogenic materials, animal manure, and human sewage contain stored chemical energy from the sun which is burned for heat or converted to fuel. This process is renewable because it can be replenished by planting trees and agricultural crops. It is not clean though because the combustion of biomass materials releases sequestered carbon dioxide, nitrogen oxides, and sulfur oxides in the biomass material into the atmosphere.

Both hydropower and biomass are renewable energy sources because they are replenishable. They are not clean though because greenhouse gases are emitted during energy generation. 

Why Is It Important to Differentiate Between Clean Energy and Renewable Energy

As with most things, there are both benefits and drawbacks to clean energy and renewable energy. It is important to differentiate between the differences because the slight differences in their definitions have different implications for our environment.

Clean energy does not produce greenhouse gas emissions, or any other environmental pollution, which aids in the fight against global climate change. However, clean energy possesses geographic limitations and offers intermittent production peaks depending on weather conditions (that could highly benefit from a smart grid). Also, when it comes to nuclear energy, safe storage and containment of nuclear waste byproducts (radioactive waste) is a big and still unsolved concern.

Renewable energy is by definition infinite because the resources naturally replace themselves over time. It is also mostly non-polluting, low-maintenance, and promotes the decentralization of energy supply. On the flip side, renewable energy comes with some of the same drawbacks that clean energy comes with, minus the threat of nuclear waste but with lower immediate quantities of energy compared to non-renewable energy sources (e.g., coal and oil). 

Although both clean and renewable energy have their own particular drawbacks, it is important to recognize that they are an integral part in helping us overcome our current climate crisis.

How Do Clean and Renewable Energy Benefit the Environment

Speaking about the current climate crisis, how could clean and renewable energy help us overcome it? Here are the three biggest benefits for us:

1. Climate Change Mitigation: clean energy does not emit carbon dioxide, nitrogen oxides, sulfur dioxides, or mercury into the atmosphere, soil, or water. These pollutants are known to contribute to the thinning of the ozone layer, global sea-level rise, and the melting of our world’s glaciers. 

2. Energy Independence: Being able to produce our own electricity in the U.S. without the aid of foreign countries is an important step to help us become more self-sufficient instead. Former President George W. Bush signed the Energy Independence and Security Act of 2007 to reduce U.S. dependence on oil, expand the production of renewable fuels (and confront global climate change). 

3. Employment Opportunities: The renewable energy sector employed 11.5 million people worldwide in 2019, with solar energy making up the bulk of those jobs. Renewable energy jobs continue to increase as we start to realize just how beneficial renewable energy is for our environment. 

Renewable energy accounted for 11% of total energy consumption in the United States in 2019. This was equal to the amount of coal consumption and was nearly three times greater than consumption in 2000. Experts predict renewable resource consumption will continue to increase through 2050 as more and more effort is put into reducing global greenhouse gas emissions. 

However, we still have a long way to go to make clean or renewable energy sources our primary form of energy. Only a very few countries have renewables as their primary energy source, while the vast majority of countries are still far off.

Final Thoughts

Despite regularly being used to describe the same thing, “clean” and “renewable” energy are two different terms with two different meanings. Although clean energy includes most renewables, it doesn’t include all of them. Likewise, not all renewable energy is clean energy.

Distinguishing between the two, and using the correct one when talking about sustainability, is important when mapping out a future that utilizes clean and renewable energy.

No energy source is perfect, but the drawbacks of clean and renewable energy should not outweigh the advantages. Clean and renewable energy produce a fraction of the greenhouse gases that burning fossil fuels does. In order to minimize the drawbacks, planning the locations and studying the environmental impacts in advance will be needed.

Stay impactful,

Sources

• National Geographic: Renewable Resources
• TWI: What is Clean Energy? How Does it Work? Why is it so Important?
• Natural Resources Defense Council: Renewable Energy – The Clean Facts
• High Country Conservation Center: What’s the Difference Between Clean & Renewable Energy?
• Office of Energy Efficiency and Renewable Energy: How Does Solar Work?
• Office of Energy Efficiency and Renewable Energy: Advantages and Challenges of Wind Energy
• Office of Energy Efficiency and Renewable Energy: How Do Wind Turbines Work?
• Office of Energy Efficiency and Renewable Energy: Geothermal FAQs
• National Renewable Energy Laboratory: Geothermal Electricity Production Basics
• National Geographic: Non-Renewable Energy
• Brittanica: Nuclear Fission
• World Nuclear Association: Uranium Mining Overview
• Office of Energy Efficiency and Renewable Energy: How Hydropower Works
• Synapse Energy Economics Inc.: Hydropower Greenhouse Gas Emissions
• U.S. Energy Information Administration: Biomass Explained
• Natural Resources Defense Council: Biomass – Not Carbon Neutral and Often Not Clean
• Green Mountain Energy: Benefits of Clean Electricity
• Scholar Schools: Advantages and Disadvantages
• White House Archives: Fact Sheet – Energy Independence and Security Act of 2007
• International Renewable Energy Agency: Renewable Energy Jobs Continue Growth to 11.5 Million Worldwide
• U.S. Energy Information Administration: Renewable Energy Explained
• Impactful Ninja: How Does the Smart Grid System Benefit the Environment
• Our World in Data: Share of Primary Energy from Renewable Sources