Alternative Energy Explained: All You Need to Know

Alternative Energy Explained: All You Need to Know

Grace Smoot

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The past two decades have seen a movement away from fossil fuels and towards more environmentally friendly substitutes. One of these substitutes is alternative energy, which can play a vital role in combating climate change because of its virtually non-existent level of CO2 emissions and because it does not harm the environment. So, we had to ask: What is alternative energy really, and how could it help us mitigate climate change?

Alternative energy emits little to no carbon emissions (12 and 48 gCO2 on a life-cycle basis), does not exhaust our natural resources, and doesn’t harm the environment. All types of alternative energy (solar, geothermal, wave, and nuclear) help combat climate change.

Keep reading to find out all about what alternative energy is, its global capacity, its carbon footprint, its environmental benefits and drawbacks, and how it can combat climate change.

The Big Picture of Alternative Energy

Alternative energy is the generation of energy from sources that do not produce greenhouse gas (GHG) emissions or significantly harm the environment, which in turn reduces the effects of global warming

How Is Alternative Energy Defined

Alternative energy is an energy substitute for fossil fuels (e.g., coal, oil, natural gas) that can reduce the effects of global warming. It does not produce GHG emissions or negatively impact the environment, making it both sustainable and environmentally friendly. 

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 GHG emissions, is non-polluting, and does not harm the environment. But it may have intermittent energy production, geographic limitations, and nuclear waste byproducts.

What Are the Different Types of Alternative Energy 

The 4 most common types of alternative energy are: solar, geothermal, wave, and nuclear energy. They are all defined as alternative energies because no GHGs are emitted during their operation and they do not negatively impact the environment. 

  • Solar energy is the conversion of sunlight into electrical energy either through the use of photovoltaic (PV) panels or solar radiation concentrating mirrors. 

Solar Energy: energy that uses the power of the sun to produce electricity”

Cambridge Dictionary
  • Geothermal energy is the conversion of heat inside of the earth into electric energy. It is created by the decay of radioactive materials in the rock and fluid of the earth’s core. 

Geothermal: involving or produced by the heat that is inside the earth”

Cambridge Dictionary
  • Wave energy is the conversion of the up and down motion of waves into electrical energy. It is created when the wind blows over the surface of the water on oceans or lakes. 

Wave Power: electrical energy generated by harnessing the up-and-down motion of ocean waves”

  • Nuclear energy occurs when a neutron strikes the nucleus of an atom, thereby breaking the atomic center into pieces and releasing energy in the form of radiation and heat. 

Nuclear Power: the power produced when the nucleus (= central part) of an atom is divided or joined to another nucleus”

Cambridge Dictionary

These 4 types of alternative energy could play an important role in mitigating climate change, so let’s have a closer look at them next.

What alternative energy isAlternative energy is an energy substitute for fossil fuels that does not produce GHG emissions or negatively impact the environment.
What the different types alternative energy areThe 4 most common types of alternative energy are: solar, geothermal, wave, and nuclear energy.
How alternative energy worksAlternative energy works by harvesting the kinetic energy of a specific alternative energy source, which turns a turbine and spins a generator to produce electricity.
The global capacity of alternative energyEach alternative energy source has a different market outlook as well as installed capacity.
The carbon footprint of alternative energyOn a life-cycle basis, the carbon footprint of alternative energy ranges anywhere from 12 to 48 grams of CO2 equivalent per kWh (gCO2/KWh) of electricity produced.
The environmental benefits of alternative energyAlternative energy promotes energy independence, creates jobs, produces less CO2 than traditional fossil fuels, and mitigates climate change.
The environmental drawbacks of alternative energyAlternative energy can cause land degradation, habitat loss, threats to terrestrial and aquatic wildlife, changes in water quality, and earthquakes, depending on the source. Nuclear waste also must be poperly handled and stored.
Alternative energy and climate changeAlternative energy combats climate change because it emits less GHG emissions than traditional fossil fuels and does not negatively impact the environment.

How Does Alternative Energy Work

In general, alternative energy works by harvesting the kinetic energy of a specific alternative energy source which turns a turbine and spins a generator to produce electricity. 

How Does Alternative Energy Actually Produce Energy

Solar energy uses either photovoltaic (PV) solar cells or concentrating solar thermal plants (CSP) to produce electricity. The former absorbs energy from sunlight, creating an electrical charge which moves in response to an internal electric field in the cell, causing electricity to flow. The latter reflects and concentrates sunlight onto receivers that collect and convert solar energy into heat. 

  • Enough sunlight strikes the surface of the earth in an hour and a half to account for the world’s energy consumption in a year. Because solar energy has such a large electricity generation potential, it is important to understand how it works.

Geothermal energy is generated when drilling down to hot water reservoirs up to a mile below the surface creates steam which is used to produce electricity.

  • Because geothermal systems have a life-cycle global warming emission of approximately 0.2 pounds of carbon dioxide (CO2) equivalent per kilowatt-hour, compared to 1.4-3.6 pounds for coal, it is important to understand how it works.

Wave energy is generated when float/buoy, oscillating water columns, and tapered channel systems use the rise and fall of waves to produce electricity. 

  • The market for wave energy is expected to reach $141 million by 2027. Because the generating potential for wave energy is so high, it is important to understand how it works.

Nuclear energy is generated when a neutron strikes the nucleus of an atom, thereby releasing energy in the form of radiation and heat. This creates steam which is used to produce electricity.  

  • Nuclear power makes up 10% of global energy generation. Because it is often described as an efficient, safe, and clean energy substitute for fossil fuels,  it is important to understand how it works.

What Is the Global Capacity of Alternative Energy

Each alternative energy source has a different market outlook as well as installed capacity: 

  • Geothermal: The potential electricity generation for geothermal is 240 gigawatts (GW), with lower and upper limits of 50 GW and 1000-2000 GW, respectively. Geothermal energy increased 200 MW to 94 TWh in 2020, a 2% increase. However, an annual increase of 13% over the years 2021-2030 is necessary to become net zero by 2050.
  • Wave: The global installed capacity of marine technology increased from 265 to 536 megawatts (MW) between 2000 and 2016. There are roughly 3,000 GW of energy stored in the world’s tides, and the market for wave energy is expected to reach $141 million by 2027. 
  • Nuclear: Nuclear capacity increased to 415 GW in 2020, and 439 reactors were in operation in 2021. According to current trends and policy targets, nuclear capacity in 2040 will total 582 GW, which is still below the 730 GW required to become net zero by 2050.

What Is the Carbon Footprint of Alternative Energy

The carbon footprint is one of the ways we measure the effects of human-induced global climate change. It primarily focuses on the GHG emissions associated with consumption, but also includes other emissions such as methane (CH4), nitrous oxide, and chlorofluorocarbons.

Carbon footprint: the amount of greenhouse gasses and specifically carbon dioxide emitted by something (such as a person’s activities or a product’s manufacture and transport) during a given period”

Merriam Webster

On a life-cycle basis, the carbon footprint of alternative energy ranges anywhere from 12 to 48 grams of CO2 equivalent per kWh (gCO2/KWh) of electricity produced.

Type of alternative energyCarbon footprint 
SolarConcentrated: 38 gCO2/KWhPV
Roof: 41 gCO2/KWhPV
Utility: 48 gCO2/KWh
Geothermal38 gCO2/KWh
WaveRelatively low, but more research is needed
Nuclear12 gCO2/KWh

Have a look at the illustration below to see the average life-cycle CO2 equivalent emissions of the alternative energy sources and how they compare to the other energy types.

Illustration of CO2 equivalent per energy source
World Nuclear Association: Average life-cycle CO2 equivalent emissions

When discussing the carbon footprint of certain alternative energy types, we must take into account carbon emissions across the energy’s building, operating, and building back phases.

The life-cycle stages of alternative energyEach stage’s carbon footprint
Building of alternative energyConstruction of alternative energy power plants and electricity delivery mechanisms.
Operating of alternative energyLittle to no CO2 emissions or waste products
Building back of alternative energyCO2 emissions from decommissioning the alternative energy power plant and subsequent land restoration

Because alternative energy has climate reduction benefits and does not harm the environment, it is important to understand what its carbon footprint is. And how its carbon emissions affect the global climate change process.

Related: Are you interested in more about the carbon footprint of alternative energy? Check it out in this article here: “What Is the Carbon Footprint of Alternative Energy?

How Environmentally Friendly Is Alternative Energy

The overall environmental friendliness of alternative energy depends on which specific type of energy is being discussed.

Environmentally friendly: (of products) not harming the environment.”

Cambridge Dictionary

There are collective, as well as unique, benefits and drawbacks to alternative energy. 

What Are the Environmental Benefits of Alternative Energy

All 4 alternative energies have the following environmental benefits:

  • Climate change mitigation: The above-mentioned alternative energies have an average life-cycle CO2 equivalent emission value between 4.5 and 48 gCO2/KWh, which is much less than, e.g., coal at 820g of CO2 equivalent per kWh. This reduction in CO2 emissions, in turn, reduces the effects of global climate change including increasing temperatures, rising sea levels, melting of sea ice, changing precipitation patterns, and ocean acidification.
  • Energy independence: Being able to produce our own electricity in the US without the aid of foreign countries is an important step to help us become more self-sufficient. 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). 
  • Employment opportunities: The renewable energy sector collectively employed 12 million people worldwide in 2020. Renewable energy jobs continue to increase as we start to realize just how beneficial renewable energy is for our environment. 

There are also specific benefits unique to each alternative energy type: 

  • Solar: Throughout its life cycle, concentrated solar energy produces 0.04%, PV roof solar energy produces 0.05%, and PV utility solar energy produces 0.06% of the CO2 emissions per unit of electricity than coal produces. 
  • Geothermal: Throughout its life cycle, geothermal energy produces 5% of the CO2 emissions per unit of electricity that coal produces. In the US alone, annual geothermal energy resources effectively offset the emission of 4.1 million metric tons (t) of CO2, 200,000 t of SO2, 80,000 t of nitrogen oxides, and 110,000 t of particulate matter when compared to conventional coal-fired plants.
  • Wave: Tidal and wave energy together could help reduce global CO2 emissions from fossil fuel electricity generation by around 500 million tons by the year 2050
  • Nuclear: Nuclear power produces 0.02% of the CO2 emissions per unit of electricity that coal produces. Over the past 50 years it has helped to avoid around 55 gigatons (Gt) of CO2 emissions, which is equal to nearly 2 years of global energy-related CO2 emissions. One U-235 pellet 1 inch tall is the equivalent of 1 ton of coal. And since 1 ton of coal creates 2.086 tons (4,172 lbs) of CO2 when it is burned, a 1-inch U-235 pellet directly avoids the emission of over 2 tons of CO2 from our atmosphere.  

What Are the Environmental Drawbacks of Alternative Energy

Each alternative energy type comes with its own set of environmental drawbacks that should be taken into account when discussing its carbon footprint. 

  • Solar: The scale of land degradation and habitat loss depends on the technology, site topography, and intensity of the solar resource. Siting large-scale solar farms on abandoned land and small-scale farms on top of buildings or homes can minimize negative environmental impacts. Water is used for the construction of PV components, and CSPs require water for cooling. Hydrochloric acid, sulfuric acid, nitric acid, hydrogen fluoride, 1,1,1-trichloroethane, and acetone are all used to manufacture PV cells. If not handled and disposed of properly, these hazardous materials could present a serious risk to environmental and public health.
  • Geothermal: Geothermal reservoirs occur deep underground and are not detectable from the surface. Areas where geothermal does come to the surface are only found near tectonic plate boundaries. Also, high-pressure fluid injections close to neighboring fault lines have the potential to trigger earthquakes. 90% of all earthquakes occur in the Ring of Fire, an area that coincides with the highest concentration of geothermal resources. 
  • Wave: The main environmental concern with tidal and wave energy is the impact on aquatic wildlife. Construction and operation of marine energy technology may negatively impact estuarine ecosystems via underwater noise pollution, habitat changes, and wildlife collisions with turbines. Because tidal and wave energy is a relatively new technology, more research needs to be done to fully understand this environmental impact. 
  • Nuclear: The main environmental drawbacks associated with nuclear power are uranium mining and nuclear waste. Uranium mining contaminates the environment with radioactive dust, radon gas, water-borne toxins, and increased levels of background radiation. Exploratory drilling and mining also heavily increases the risk of water contamination. The waste that nuclear energy does produce is radioactive and can remain hazardous for many thousands of years. These radioactive waste products include uranium mill tailings, spent (used) reactor fuel, and other radioactive wastes Proper handling, transportation, storage, and disposal of radioactive waste can help ensure that it does not leach into the environment. 

Why Is Alternative Energy Important to Fight Climate Change

Fossil fuel combustion is the main contributor to atmospheric CO2 levels. Climate Change occurs when CO2 and other air pollutants absorb sunlight and solar radiation in the atmosphere, trapping the heat and acting as an insulator for the planet. Since the Industrial Revolution, Earth’s temperature has risen a little more than 1 degree Celsius (C), or 2 degrees Fahrenheit (F). The current global annual temperature rise is 0.18C, or 0.32F, for every 10 years. 

Using alternative energy (solar, geothermal, wave, and nuclear), instead of fossil fuel energy helps mitigate the following negative effects of climate change:

  • Melting of sea ice: Since 1979, arctic sea ice has declined by 30%. Sea ice plays a major role in regulating the earth’s climate by reflecting sunlight into space and providing habitat for animal species. If all of the glaciers on Earth melted, sea levels would rise by approximately 70 feet, effectively flooding out every coastal city on the planet. 
  • Changing precipitation patterns: Extreme weather events (e.g., hurricanes, floods, droughts) are becoming more common and more intense. Storm-affected areas will experience increased precipitation and flooding whereas areas located further from storm tracks will experience decreased precipitation and droughts.
  • Ocean acidification: The ocean absorbs 30% of the CO2 released into the atmosphere, which decreases the pH (increases the acidity) of the ocean. In the past 200 years, the pH of oceans has decreased by 0.1 pH units, which translates to a 30% increase in acidity. Aquatic life unable to adjust to this rapid acidification will die off. A prime example of this is coral bleaching, where coral expel the algae (zooxanthellae) living in their tissues as a result of changes in temperature, light, or nutrients. 

Experts claim that to avoid a future plagued by rising sea levels, acidified oceans, loss of biodiversity, more frequent and severe weather events, and other environmental disasters brought on by the hotter temperatures, we must cut current GHG emissions by 50% by 2030 and reach net zero by 2050, as outlined in the 2015 Paris Climate Agreement.

The more we reduce CO2 emissions, the more we slow the rate of temperature rise, sea-level rise, ice melting, and ocean acidification. When these rates are slowed, the earth’s biodiversity does not have to struggle to adapt to temperature and pH changes. People will not be displaced due to the flooding of coastal areas. And icebergs will continue to provide climate regulation. 

Final Thoughts

Alternative energies have gained traction since 2000 because they do not emit greenhouse gases and do not harm the environment. They emit less GHGs than traditional fosssil fuels and have a lower carbon footprint across their building, operating, and building back phases. Harnessing the kinetic energy of alternative energy (solar, wind, micro/low hydropower, geothermal, and wave energy) spins a turbine and powers a generator to produce electricity. 

Alternative energies also create jobs and promote energy independence, making them environmentally friendly energy sources. Careful siting of power plants and proper disposal of nuclear waste byproducts can help mitigate environmental concerns. Alternative energies benefit both our atmosphere and Earth’s biota.

Stay impactful,

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Grace Smoot

Grace loves to research and write about all things related to climate action and sustainability. She holds a Bachelor’s of Science degree in Environmental Biology and works as an Environmental Survey Technician. Outside of work, she loves to work out, play soccer, and take her dog for long walks.

Did you know that the internet is a huge polluter of the environment? But fortunately not this site. This site is powered by renewable energy and all hosting-related CO2 emissions are offset by three times as many renewable energy certificates. Find out all about it here.

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