By
Grace Smoot

Water contains approximately 1,000 times the kinetic energy of wind, making it an energy-dense source. Harnessing the power stored in our oceans’ waves is a low emissions process that can help transition us away from fossil fuels. So, we had to ask: What is wave energy really, and how can it help mitigate climate change?

Wave energy is the conversion of the movement of ocean water volumes into electrical energy. Per KWh produced, wave energy emits low levels of CO₂, although more research is needed. Wave energy helps combat climate change and has various environmental benefits, however, it is still in the research and development phase.

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

The Big Picture of Wave Energy

Wave energy contributes to the avoidance of greenhouse gas (GHG) emissions from the burning of fossil fuels (e.g., coal, oil, natural gas). It is classified as a renewable energy source because the resource (water) naturally replaces itself over time. 

How Is Wave Energy Defined

Wave energy is defined as the conversion of the movement of ocean water volumes into electrical energy through the use of various wave energy technology systems.

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

Britannica

Waves are formed when the wind blows over the surface of the water on oceans or lakes. 95% of the wave’s energy is stored between the surface of the water and the top 1/4th of the wave’s length. 

What Are the Different Types of Wave Energy 

There are three types of wave energy technology:

• Float or buoy: Anchored buoys use the rise and fall of waves to power hydraulic pumps. The “up” and “down” movement powers a generator to produce electricity, which is transported onshore via underwater power cables. 

• Oscillating water column: The “in” and “out” motion of waves at the shore enter columns, forcing air to turn turbines. As the waves enter the column, the air is compressed and heated, creating energy. The energy is then transported onshore via underwater power cables. 

• Tapered channel (tapchan): Shore mounted structures channel and concentrate waves, pushing them into an elevated reservoir. The water is then released from the reservoir, flowing through penstocks and to turbines which power a generator to produce electricity. 

What wave energy is	Wave energy is defined as the conversion of the movement of ocean water volumes into electrical energy through the use of various wave energy tecnology systems.
What the different types wave energy are	The three types of wave energy technology are float/buoy, oscillating water column, and tapered channel systems.
How wave energy works	Wave energy is generated when float/buoy, oscillating water column, and tapered channel systems use the rise and fall of waves to produce electricity.
The global capacity of wave energy	The market for wave energy is expected to reach $141 million by 2027. Very few countries currently produce wave power, with the energy still being in research and development phase.
The carbon footprint of wave energy	More research needs to be performed on wave systems, but they produce very little CO2 emissions.
The environmental benefits of wave energy	Wave energy is a predictable, stable, and concentrated energy source that mitigates climate change, promotes energy independence, and creates jobs.
The environmental drawbacks of wave energy	Wave energy may negatively impact estuarine ecosystems and faces various technological challenges.
Wave energy and climate change	Wave energy combats climate change by mitigating the temperature rise, sea-level rise, ice melting, and ocean acidification associated with global warming.

How Does Wave Energy Work

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

How Does Wave Energy Actually Produce Energy

Wave energy operates in the following way:

• Float or buoy: The “up” and “down” motion of waves moves buoys. The kinetic energy produced powers a generator to produce electricity. 

• Oscillating water column: The “in” and “out” motion of waves at the shore enter columns, compressing and heating the air inside, turning turbines, and powering generators to produce electricity. 

• Tapered channel (tapchan): Tidal waves are forced into an elevated reservoir. When water is released from the reservoir, it flows through penstocks, turns turbines, and powers generators to produce electricity. 

The electricity is then transported to a substation where it is transmitted to consumers by transmission lines. Transformers receive the electricity and either increase or decrease the voltage as needed before it can be delivered to consumers. 

What Is the Global Capacity of Wave Energy

The market for wave energy is expected to reach $141 million by 2027. Very few countries currently produce wave power, with the energy still being in the research and development phase. 

Marine (wave and tidal) energy installed capacity has increased over the past 20 years, but its development worldwide has been disproportionate. Europe and Asia have seen far more growth when compared to the rest of the world. 

The Aguçadora wave farm in Portugal was the world’s first operational wave power system. It had a 2.25 MW generating capacity and consisted of jointed tubes that floated on the surface of the Atlantic Ocean and harnessed energy from the “up” and “down” motion of the waves. It was discontinued due to maintenance issues. 

PacWave South, an Oregon State University-led project, is a 2 square mile patch of ocean located 7 miles off of the Oregon coast. Scheduled for completion in 2023, it is a site where companies and developers can test their wave energy technologies for eventual market use. 

Wave energy is not as developed when compared to the traditional renewable energies (e.g. solar, wind, hydropower, biomass, and geothermal). This is largely due to a lack of funding because of the high upstart and maintenance costs. As technology becomes cheaper to implement, experts predict that wave energy will increase in production.

The marine energy market size is predicted to reach $28 billion by 2030, increasing at a compound annual growth rate of nearly 42%. Because the market potential for wave energy is so high, it is important to understand what wave’s carbon footprint is, and how its carbon emissions affect the global climate change process.

What Is the Carbon Footprint of Wave Energy

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

“Carbon footprint: the amount of greenhouse gases 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

Basically, it is the amount of carbon emitted by an activity or an organization. This includes GHG emissions from fuel that we burn directly (e.g., heating a home, driving a car) and GHG emissions from manufacturing the products that we use (e.g., power plants, factories, and landfills). 

More research needs to be performed on wave systems, but research suggests they produce very little CO₂ emissions. 

Have a look at the illustration below to see the average life-cycle CO₂ equivalent emissions of different energy sources. Wave energy is estimated to produce a fraction of the emissions of coal power plants, which produce an estimated 820 gCO₂ per KWh.

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

The life-cycle stages of wave energy	Each stage’s carbon footprint
Building of wave energy	CO2 emissions from construction and transportation of materials
Operating of wave energy	Little to no CO2 emissions or waste products
Building back of wave energy	More research is needed

There are very few CO₂ emissions or waste products associated with operating wave energy, making the carbon footprint of this phase very low. CO₂ emissions at this stage are associated with the operation of the mechanical equipment (e.g., buoys, water columns, turbines, generators, substations, transformers) at the wave energy power plants. 

Little is known about the life expectancy of wave energy power plants because the technology is still in development and has not been implemented on a commercial scale for an extended period of time. Factors that should be taken into account when calculating the lifespan would include the physical force of the wave hitting the machinery and the saltwater’s corrosive abilities. 

Wave energy is a low-carbon emitting energy source with a large energy generation potential, therefore it is important to understand what its carbon footprint is and how its carbon emissions affect the global climate change process.

How Environmentally Friendly Is Wave Energy

The environmental impacts of wave energy come down to its effect on the marine ecosystem in which it is constructed. 

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

Cambridge Dictionary

Although it is not nearly as developed as other renewable energies, wave energy comes with a host of environmental benefits and only minimal drawbacks. 

What Are the Environmental Benefits of Wave Energy

Wave energy has the following environmental benefits: 

• Climate change mitigation: Wave energy can help reduce global CO₂ emissions from fossil fuel electricity generation. 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.

• A predictable, stable, and concentrated energy source: Unlike other renewable energies (solar and wind), marine energy is available for use 24/7, 365 days a year. Waves can produce the same amount of energy with less materials and in a fraction of the space required by other renewable energies. 

• 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. 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. 

Wave energy helps mitigate climate change through reduced CO₂ emissions while promoting energy independence and creating jobs. 

What Are the Environmental Drawbacks of Wave Energy

The main environmental concern with both 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 are relatively new technologies, more research needs to be done to fully understand this environmental impact. 

The other main drawback to wave energy is technological challenges. Wave energy receives little funding for research and development, and it is expensive to construct and maintain the massive machines that are used in the ocean. Salt water’s ability to corrode metal, coupled with the physical impact of waves hitting the machinery, transmission lines, and other infrastructure makes implementing wave energy difficult on a large scale. 

Why Is Wave Energy Important to Fight Climate Change

Climate change is arguably the most severe, long-term, global impact of fossil fuel combustion. Every year, approximately 33 bt of CO₂ are emitted from burning fossil fuels. The carbon found in fossil fuels reacts with oxygen in the air to produce CO₂. This warms the earth by acting as a heating blanket, and a warmer earth comes with a host of negative side effects. 

Marine energy could help reduce global CO₂ emissions from fossil fuel electricity generation by around 500 million tons by the year 2050. Using wave energy instead of fossil fuel energy helps mitigate the following negative effects of climate change:

• Increasing temperatures: Earth’s atmosphere has warmed 1.5℃ since 1880. This may not seem like a lot, but these degrees create regional and seasonal temperature extremes, reduce sea ice, intensify rainfall and drought severity, and change habitat ranges for plants and animals.

• Rising sea levels: Global sea levels have increased approximately 8-9 inches since 1880, displacing people living along coastlines and destroying coastal habitats. Roads, bridges, subways, water supplies, oil and gas wells, power plants, sewage treatment plants, and landfills remain at risk if sea level rise goes unchecked. 

• 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. 

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. 

To help keep global temperature rise below 1.5C, as outlined in the Paris Agreement, we must shift at least 80% of our electricity generation to low carbon sources. Over 120 countries have already stated their net-zero carbon emissions ambitions for 2050 or 2060. But only 12 countries have thus far proposed or enacted any legislation, indicating that there is more work to be done.

Final Thoughts

Wave energy harnesses the kinetic energy stored in ocean waves and converts it into electrical energy via various syetems. It is a renewable energy source with a low carbon footprint across its building, operating, and building back phases although more research is needed to determine a specific life-cycle carbon emissions value.

Although it is still in the research and development phase, wave energy has great potential to help mitigate climate change. Waves hold significantly more kinetic energy than wind energy and can therefore generate a lot of electricity. Further research and development is needed to enhance the technology and explore possible adverse effects of marine systems on aquatic life. But overall, wave energy benefits both our atmosphere and Earth’s biota.

Stay impactful,

Sources

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