Clean and alternative energy are commonly used synonymously when talking about sustainable options to replace fossil fuels. Sometimes this is correct, but there are instances where the two are not mutually exclusive. Understanding these differences is key in making informed decisions about energy sources. So we had to ask: What’s the difference between clean and alternative energy?

Clean energy is the generation of energy that does not produce greenhouse gas emissions. Alternative energy is the generation of energy that does not produce greenhouse gas emissions or harm the environment. Knowing the difference between the two aids in the fight against global climate change.

So, how can we tell the difference between clean and alternative energy? Can an energy source be categorized as one but not the other? What are the benefits and drawbacks of each? Find out the answers to all of these questions below, and see what this means as we strive for a more sustainable future. 

How Are Clean Energy and Alternative Energy Defined

Clean and alternative energy are not mutually exclusive, despite what a quick google search might tell you. Although they share the same end goal of reducing global greenhouse gas emissions, their impact on the environment is what separates the two.

What Does the Dictionary Say About Clean Energy and Alternative Energy

Clean and alternative energies are substitutes for fossil fuels (e.g. coal and oil) that produce fewer greenhouse gas emissions and have less of a negative impact on the environment.

“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.

“Alternative Energy: electricity or power that is produced from the sun, wind, water, etc. in ways that do not use up the earth’s natural resources or harm the environment”

Oxford Dictionary

Alternative energy does not produce greenhouse gas emissions that contribute to global warming or cause substantial harm to the environment.

Both clean and alternative energy sources do not produce greenhouse gas emissions, but only alternative energy sources do not harm the environment. 

What Do These Differences Mean

The differences in the definitions of clean energy and alternative energy have different ramifications on our environment:

• If energy is only clean but NOT alternative: the generation of energy does not produce greenhouse gases (or other pollution), but it has the potential to harm the environment. For example, wind power does not emit greenhouse gases, but wind turbines pose a threat to flying wildlife, and the land use requirement for wind farms is extensive.

• If energy is only alternative but NOT clean: This category does not exist because all alternative energy is by definition also clean energy. Alternative energy does not emit greenhouse gases AND does not harm the environment, while clean energy “only” does not emit greenhouse gases (but may or may not harm the environment). 

In short, clean energy means zero greenhouse gas emissions, but it can potentially harm the environment. Alternative energy does not pollute the atmosphere or harm the environment.

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

By using energy sources that are clean or alternative as a replacement for fossil fuels, we can reduce the amount of greenhouse gases entering the atmosphere and preserve the natural state of the environment. And an even better way to maximize the benefits is to utilize energy sources that are both clean and alternative!

After researching whether an energy source produces greenhouse gases or harms the environment, we can effectively categorize the following five energy sources as either clean and alternative, only clean, or neither.

Which Energies are Both Clean Energy and Alternative Energy

If energy is both clean AND alternative, the generation of energy does not produce greenhouse gases or harm the environment. Below are the energy sources that are both clean and alternative.

• 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 alternative because it minimizes any negative environmental impacts by only drilling to shallow depths and by recycling the water used.

• 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 also alternative because this process does not harm the environment (not counting any accidents).

• 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. Solar is also alternative because it does not harm the environment. Following proper disposal methods of hazardous chemicals associated with PVCs and placing solar panels in less populated areas or on top of buildings minimizes any negative environmental impacts.

Geothermal, nuclear, and solar are both clean and alternative energies because the generation of energy does not produce greenhouse gases or damage the environment. 

Which Energies Are Only Clean Energy But Not Alternative Energy

If energy is only clean but NOT alternative, the generation of energy does not produce greenhouse gases, but it does harm the environment. Below are the energy sources that are clean but not alternative.

• 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 not alternative though because spinning turbine blades pose a threat to flying wildlife, and the land use requirement for wind farms is very high. 

Wind power is clean energy but not alternative energy because its energy production negatively impacts the environment in some way.

Which Renewable Energies Are Neither Clean Energy Nor Alternative Energy

If energy is NEITHER clean NOR alternative, it either produces greenhouse gases, harms the environment, or both. Below are the renewable energy sources that are neither clean or alternative. But, as you’ll see, they are still important in aiding our fight against climate change.

• Biomass: Wood, agricultural crops, biogenic materials, animal manure, and human sewage contain stored chemical energy from the sun which is burned for heat. This process is not clean because the combustion of biomass materials releases sequestered greenhouse gases in the biomass material into the atmosphere. Albeit, the amount released is much less than is released from fossil fuels. It is also not alternative because the biomass industry is responsible for clearcutting forests and reducing both plant and animal biodiversity.

• Hydropower: Flowing water turns turbines, which spins a generator to generate electricity. This process is not clean because the construction of hydroelectric facilities and biomass decomposition in the reservoirs produces carbon dioxide and methane, although the rate of emissions is much lower than that of fossil fuels. It is also not alternative because dams that create reservoirs can obstruct fish migration, alter the water temperature and chemistry, and flood out adjacent lands. However, hydropower still has less of a negative effect on the environment than fossil fuels.

So if an energy source is neither clean nor alternative, does this mean we shouldn’t use it as a replacement for fossil fuels? Absolutely not! Both biomass and hydropower are still viable substitutes for fossil fuels because they have lower rates of greenhouse gas emissions and are renewable.

Biomass may not be clean or alternative, but it is a renewable resource because it can be replenished by planting trees and agricultural crops. The quantity of greenhouse gases released and the level of environmental impact of biomass can be reduced by planting fast-growing trees, utilizing efficient stoves, and having strict air pollution control regulations.

Hydropower may not be clean or alternative, but it is a renewable resource because the water cycle is a continuous process that recharges itself. The quantity of greenhouse gases released and the level of environmental impact of hydropower can be reduced by planning land use around river basins upstream of dams and constructing fish ladders that help with migration patterns. 

By using hydropower instead of coal or natural gas we can still drastically reduce carbon emissions. To be more specific, per kilowatt-hour of electricity generated, hydropower only emits 2.3% of carbon dioxide-equivalent as compared to coal (18.5g vs 820g) and 3.8% as compared to natural gas (18.5g vs 490g) – when taking into account their whole life-cycle.

Why Is it Important to Differentiate Difference Between Clean and Alternative Energy

Clean energy and alternative energy have benefits and drawbacks which are important to understand when deliberating which energy source to use.

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.

Alternative energy does not produce greenhouse gases or negatively impact the environment, making it a good alternative to fossil fuels. On the other hand, it can have intermittent production and geographic limitations which could benefit from technology such as the smart grid. The disposal of nuclear waste and containment of radioactive material are other issues that need to be addressed when considering implementing this energy source. 

The drawbacks to clean and alternative energy should not be overshadowed by the benefits, which play an important role in fighting the current global climate crisis.

How Do Clean and Alternative Energy Benefit the Environment

Here are three ways in which clean energy and alternative energy can help us overcome the current global climate crisis and lead us to a more sustainable future: 

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. Also, alternative energy does not negatively impact the land, water, or biodiversity of our environment.

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. 

However, we still have a long way to go to make clean or alternative 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 very far off. 

Most countries generate only a small percentage of their energy from renewables, and the U.S. only generated 8.71% of its energy from renewables in 2019. Incorporating clean and alternative energy sources like solar, geothermal, and nuclear energy into our current energy mix would cut down on greenhouse gas emissions and carve a path towards a more sustainable future.

Final Thoughts

Despite what some may tell you, clean and alternative energy are two different sustainability terms with two different meanings. Both clean and alternative energy do not pollute the atmosphere with greenhouse gases, but alternative energy has the added benefit of not harming the environment. Therefore, not all energy sources are both clean and alternative, and some energy sources do not fit into either category. 

Of the five energy sources mentioned above, biomass and hydropower are neither clean or alternative. But this doesn’t necessarily make them a bad choice when discussing substitutes for fossil fuels! Other factors must be considered, like if the energy source is renewable, before we can make decisions regarding future ways to generate energy more sustainably.

Stay impactful,

Sources

• TWI: What is Clean Energy? How Does it Work? Why is it so Important?
• New World Encyclopedia: Alternative Energy
• Office of Energy Efficiency and Renewable Energy: Geothermal FAQs
• National Renewable Energy Laboratory: Geothermal Electricity Production Basics
• Brittanica: Environmental Effects And Economic Costs
• National Geographic: Non-Renewable Energy
• Brittanica: Nuclear Fission
• High Country Conservation Center: What’s the Difference Between Clean & Renewable Energy?
• Office of Energy Efficiency and Renewable Energy: How Does Solar Work?
• Union Of Concerned Scientists: Environmental Impacts of Solar Power
• 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: Environmental Impacts and Siting of Wind Projects
• U.S. Energy Information Administration: Biomass Explained
• U.S. Energy Information Administration: Biomass and the Environment
• Natural Resources Defense Council: Biomass – Not Carbon Neutral and Often Not Clean
• Leonardo DiCaprio Foundation: Dangerous delusions – biomass is not a renewable energy source
• Office of Energy Efficiency and Renewable Energy: How Hydropower Works
• Synapse Energy Economics Inc.: Hydropower Greenhouse Gas Emissions
• U.S. Energy Information Administration: Hydropower and the environment 
• Union Of Concerned Scientists: Environmental Impacts of Hydroelectric Power
• U.S. Energy Information Administration: Biomass and the Environment
• International Hydropower Association: Greenhouse Gas Emissions