Riding the Wave of Renewable Energy

There is something severely frigid about surfing in the Pacific Ocean of Northern California in winter. No matter the wetsuit you are wearing, your hands and face are engulfed in the icy seawater that’s so cold your hands are numb within the first ten minutes of paddling. To get out to the waves, you have to surpass the white water that pulls you back to shore and walls of crashing waves that pound you, seawater finding its way into your nose, mouth and eyes.

And yet, there is nothing more satisfying than catching a wave or riding down its face and feeling the power of the ocean push you forward. It’s exhilarating. It’s no wonder, then, that on good (and sunny) days the waves are crowded with surfers all trying to capture that power and feeling, even if just for a moment. Humanity has taken advantage of that power since the late 700s. Now, the first people to surf didn’t pop up until around the 1200s in Polynesia. But I’m not referring to surfing. Humans have been using the ocean, or rather the waves and tides that come from the interaction of the ocean and the moon, to power our mechanical contraptions for nearly 1500 years. The first of such devices to harness the power of water is a tide mill from the year 787 that used tidal barrage to turn a grindstone and grind grain.

In general, tidal power is the method of harnessing the natural movement of the tides caused by the moon’s gravitational pull and the rotation of the Earth to turn a turbine and generate electricity. This resource is clean, renewable, sustainable and has no fuel cost, with the added benefit of the predictability of tides being predictable. One of the difficulties of renewable energy in other sectors like wind and solar is the uncertainty of how often the wind will blow, or the sun will shine month to month or year to year.

Tidal barrage is one of three forms of harnessing tidal energy to generate electricity, the others being tidal stream generation and dynamic tidal, although dynamic tidal is still theoretical. Tidal barrage is like a dam, in that there is a turbine inside the barrage that generates electricity when the high tide comes in. When the tide goes out, it uses gravity to once again turn the turbine. The settlers of Maine built such mills along most of the coastline to grind grain. Tidal stream generation is when a single device or group of devices are placed in tidal streams to capture the energy from the current. These systems can capture energy in both directions, when the tide comes in and goes out.

Currently, there is no commercially operating tidal energy power plant in the US, but one may be coming soon. There are several projects in the works to start generating electricity along the coastline using tidal barrage systems. Maine in particular is becoming a hotspot for tidal power. Maine’s Cobscook Bay is one such place, which, after a successful demonstration project on the bay, spurred an energy company to make plans to install a commercial system by the end of the year. It would initially provide power for 50–75 homes in the area, and eventually scale up to 1,200 homes and businesses. Eastport, Maine, a location constantly battered by waves and storms and facing consistent and disruptive power outages, is looking to tidal power to maintain a microgrid. Harnessing the tidal power would decrease the volatility of energy prices in a city that pays nearly double the national average per kWh. Tidal would bring energy independence and help build the community’s storm resiliency.

Further down the coast, two engineers – University of New Hampshire doctoral candidates – in collaboration with the National Renewable Energy Laboratory, Sandia National Laboratories, and the Pacific Northwest National Laboratory, designed a tidal energy turbine that will collect and share data to deepen understanding of tidal energy while helping to power a drawbridge in Portsmouth, New Hampshire. In New York City, Verdant Power conducted similar research and testing over the past two decades and has designed the Roosevelt Tidal Energy Project (RITE), located in the East Channel of the East River. RITE successfully tested a multi-turbine tidal array using tidal stream generation with a horizontal-axis turbines which, depending on the flow of the tide, rotate in both directions.

Over the course of a nine-month demonstration, they generated 300 MWh of electric energy for the grid, the amount needed to power approximately 30 average households for a year. On the opposite coast, the wave energy tech developer CalWave recently signed a memorandum of understanding with AltaSea at the Port of Los Angeles, establishing a formal partnership to work toward creating a local wave energy industry and building projects off the coast of California. Tidal is just starting to emerge, but a recent study in Europe found that wave energy has the potential to rival offshore wind costs as soon as the 2030s.

As humanity confronts the stark reality of sea level rise, what better way to adapt and overcome, than to use the sea to generate energy? Tidal power has been around for centuries, and harnessing the oceans is nothing new. There is vast potential here, especially as more companies jump in to research electricity generation. There are also numerous additional benefits to harnessing tidal energy, such as the regional benefits a town might gain from using tidal energy generation as a form of storm resiliency. Tidal energy can help diversify energy markets further and increase the renewable energy resource mix. And, as sea levels continue to swell, tidal energy will be even more worthwhile since underwater turbines still function no matter how high the sea level. This renewable source can also be localized to coastal towns, helping with microgrids and communities that experience isolation from power grids during big storms. Humanity has long respected or even feared the oceans for their power and ease in flipping a surf board or a ship. By harnessing that awesome power, we may be able to ride those waves towards the beacon of a more energy resilient and renewable future, even as we anticipate more stormy weather from our changing climate.

RCC Stanback Fellow – Jackson Ronald

Jackson Ronald is a Master of Environmental Management student at Duke University studying Environmental Economics & Policy and Energy in the Environment. Deeply curious and interested in the environment, he is passionate about the intersection of environmental law, indigenous justice and the energy transition.