6 Jul, 2022
NJ bill taps into potential for harnessing power of ocean waves, tides
By Siri Hedreen
| A tidal power turbine in Halifax Harbor, Nova Scotia. |
In the wake of gains in wind, solar and geothermal energy, pilot projects and policy proposals are looking to harness another force of nature — the oceans' waves and tides.
The latest is a bill recently introduced in the New Jersey state legislature that aims to turn the Garden State into the "nationwide leader in ocean energy." Democratic Assemblyman Robert Karabinchak sponsored the bill, which would require a study of the state's ocean energy potential and direct the New Jersey Board of Public Utilities to set goals for wave and tidal power.
"Energy is going to change in the future. Whether wind turbines [off the shore of] Atlantic City, or solar farms, this is the start of clean energy in New Jersey," Karabinchak said at an ocean energy hearing in March. "However, there are other sources of energy."
New Jersey has roughly 130 miles of coastline along the Atlantic Ocean. The theoretical energy potential of waves off U.S. coasts is estimated to be up to 2.64 trillion kWh of energy annually, according to the U.S. Energy Information Administration. That is the equivalent of 66% of U.S. electricity generation in 2020.
The role tides play in electricity generation
The ebb and flow of water can also be harnessed for electricity using several generating technologies, such as a tidal barrage, which functions like a two-way dam. Tidal barrages are generating electricity in several locations worldwide; the largest project, Korea Water Resources Corp.'s Sihwa Tidal Project in South Korea, is capable of generating 254 MW of electricity. But tidal barrage generation comes with several potential downsides, including being harmful to marine ecosystems or impeding oceangoing vessels.
The changing flows can also turn tidal turbines, either stand-alone — resembling an underwater wind turbine — or attached to a floating power station. In Nova Scotia, a Scottish company's floating tidal energy project delivered its first power to the grid in May. Sustainable Marine Energy Ltd. estimates tidal energy from the Bay of Fundy could be harnessed to provide Canada with up to 2,500 MW of renewable energy.
The underwater turbines can be a trade-off. A tidal turbine captures more energy than a wind turbine with the same-sized blades, according to the EIA. However, because water is denser than air, tidal turbines must be heavier and sturdier and therefore are more expensive than their land counterparts.
New wave technologies in development
Waves are powered by different forces, formed by wind blowing over the ocean's surface. Various nascent technologies are being tested in the U.S. to utilize that power. One proposal is to channel waves into a cliffside reservoir through a funneled passage, spinning a turbine. Another project, led by Oregon State University, will test several models of wave energy devices, resembling buoys, to capture the waves' movement and transmit that energy through cables buried beneath the ocean floor.
However, neither wave nor tidal energy has been deployed at a commercial scale in the U.S. The EIA identifies several U.S. locations that could be tapped for tidal energy, including the Cook Inlet of Alaska, with the second-highest tidal range on the continent, and several locations in Maine where development projects are already underway. A body of water's tidal range must be at least 10 feet to be economically worthwhile, according to the federal agency.
As for wave energy, a 2020 study by the DOE's Pacific Northwest National Laboratory identified Washington's and Oregon's coastlines as most promising, due to unique geographical features that funnel waves into "energy hotspots."
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