There are currently three tidal turbine projects in the country — two in Maine and one in New York. The first Maine site tested a 150-kilowatt underwater turbine from 2012 to 2013 and is now benchmarking the performance of a newer generation of the same device.
Evaluating the Present and Future Potential of Tidal Power in the U.S.
Martin Banks, Editor | Modded
Renewable energy sources have never been more important. The 2050 target for reaching net zero emissions is inching ever closer, but the nation’s reliance on fossil fuels has not seen any dramatic change. In all likelihood, the country will need new sources of clean energy beyond what’s already in use. Tidal power could be an ideal solution.
Hydroelectric power is nothing new — it’s one of the oldest forms of renewable electricity — but it’s historically relied on dams in freshwater bodies. Tidal installations apply the same concept to the ocean. As tides rise and fall, specialized infrastructure converts the water’s natural movement into electricity.
Benefits of Tidal Power
Harnessing ocean waves for electrical power has several advantages. As it becomes more common and climate change worsens, these benefits become harder to overlook.
1. Sustainability
The most obvious upside to tidal power is that it’s emissions-free. Renewables account for just 21.4% of electricity generation in the U.S. While this figure has seen a marked increase over the past decade, it’s still far below the level needed to stave off the worst effects of climate change.
Since tidal energy relies solely on natural water motion to generate electricity, it produces no greenhouse gas (GHG) emissions. That’s an improvement over conventional hydropower, too. While dams don’t release harmful emissions to create fuel, their reservoirs can contribute to soil degradation and decaying biomass within the water as it heats up. Consequently, such structures still produce some emissions.
Tidal energy farms, by contrast, do not need reservoirs, so they do not share the same emissions concerns. They’re also 100% renewable because they don’t consume water but rather react to its movement.
2. Power Capacity
It’s also worth noting that tidal energy has a higher power capacity than other renewables. Water is denser than air, so moving at the same speed will push a rotor of the same size a greater relative distance than a wind turbine, generating more electricity.
Likewise, a tidal energy rotor will produce a greater amount of electricity over a given period than a solar panel of a similar size. It also requires less upkeep and infrastructure than a nuclear plant.
This factor is important because other green energy initiatives have struggled to keep up with demand. U.S. GHG emissions have fallen by just 0.01% annually since 1990, suggesting the need for far greater renewable capacity. Tidal power’s energy density could help overcome that gap.
3. Reliability
Similarly, tidal power is more reliable than wind or solar energy. While other renewables are clean and all are important in the fight against climate change, they’re intermittent. Wind speeds shift, and sunlight fades, so such systems require storage to sustain their service areas’ electrical demand.
By contrast, ocean currents are relatively consistent. While the tide does rise and fall, these cycles are predictable, and some amount of motion still occurs at all times. Consequently, a tidal energy farm generates electricity around the clock, providing continuous power without the need for expensive battery or fuel cell storage.
Tidal energy’s reliability is a welcome change over solar power’s duck curve, which has worsened with each year as solar capacity increases, leading to waste. It wouldn’t need to replace other renewables to provide benefits, either. Its consistency could serve as a complement, filling the gaps when other sources struggle to meet current demands.
Tidal Power in the U.S. Today
Tidal energy is still a relatively new concept, so it has yet to see widespread adoption. However, a few early installations have emerged across the U.S. in recent years.
There are currently three tidal turbine projects in the country — two in Maine and one in New York. The first Maine site tested a 150-kilowatt underwater turbine from 2012 to 2013 and is now benchmarking the performance of a newer generation of the same device. The other Maine installation will use this same technology to provide up to 500 kW of clean electricity to the nearby grid through undersea cables.
The New York project, like the first Maine site, served as a testing ground. While it’s no longer in commission, the installation successfully tested a 105 kW turbine array in the East River off of Manhattan.
Despite the small scale of these projects, future tidal power installations will appear. In 2022, the Department of Energy announced $35 million in funding for tidal and river current power systems as part of the Bipartisan Infrastructure Law.
Remaining Obstacles
While tidal energy shows considerable potential, there are still some roadblocks in the way. Like many renewables, costs are among the largest concerns. Installing and maintaining underwater turbines is expensive, so it’s difficult for utility organizations to justify it.
There are also geographic limitations to consider. Not every shore or channel has a strong enough current to produce enough electricity to warrant the costs and complexity of installation. Climate change could worsen such restrictions, as rising waters affect both currents and the gap between high and low tides. Considering the rate of rising sea levels is increasing by 0.13 inches a year, that could pose a challenge before long.
Some experts worry about the ecological impacts, too. Adding moving infrastructure to underwater environments could disrupt undersea wildlife. Research is currently underway to understand these effects, but for now, it’s uncertain whether tidal energy farms would disrupt migratory patterns or injure fish passing through the area.
The Future of Tidal Power in the U.S.
Despite lingering challenges, tidal power is still moving forward. With technological advancement, costs and installation complexity will become smaller issues over time. Government investment should also help ease the expenses.
Future projects may also focus on floating tidal energy converters (FTECs) instead of submerged turbines. Because FTECs rest on top of the water instead of moving beneath it, they avoid wildlife interactions. Studies show that combining these solutions with conventional turbines can improve energy production by up to 30%, which could offer an ideal balance between capacity and safety.
Tidal Power Is Promising But Uncertain
No one energy source will be the answer to the world’s fossil fuel problems. Tidal power is a promising solution, but like others, it has its fair share of downsides. Investing in related research and combining this innovation with other renewables is key to an effective green electricity transition.
The content & opinions in this article are the author’s and do not necessarily represent the views of AltEnergyMag
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