Marine Energy—The Future Wave of Clean Energy
New energy technologies are constantly on the horizon, which leaves us to wonder—what could be the next big thing? In the United States, renewable energy projects have been primarily utility scale solar and on-shore wind. But across the pond, marine energy is making a splash.
Leyline Renewable Capital recently sat down with Richard Ainsworth, a U.S. project engineer with the European Marine Energy Center in Scotland, and George Bonner, director of the North Carolina Renewable Ocean Energy Program at the N.C. Coastal Studies Institute, to discuss the potential deployment of marine energy here in the United States.
What is Marine Energy? How Is It Different from Wave Energy and Tidal Energy?
Marine or ocean energy is composed of both wave energy and tidal energy. The ocean’s tides and waves produce kinetic energy, which is harnessed and converted to electricity. Wave energy is created by capturing energy from ocean waves, while tidal energy harvests power from the movement of tidal swells.
There are three main types of wave energy technologies:
- Floats/buoys, which utilize ocean swells to drive hydraulic pumps and generate electricity.
- A cylindrical shaft (typically on the shoreline), which uses an oscillating water column that, as water rises and falls, creates wind to power a turbine and generate electricity.
- A tapered channel, which concentrates waves and drives them into a reservoir where they generate power via a turbine.
As with many renewable energy sources, developing efficient technologies is the key to viability. Wave energy is a great, reliable power source, but compared to other renewables, Ainsworth says we are still about 10 years behind in development. Once refined, however, it could be a flexible and effective option with applications across the globe.
Tidal energy is a different story, as it’s been much quicker to converge on distinct and productive technologies. It’s also a predictable resource—tidal change is easy to track. But this form of energy generation faces the challenge of geographic specificity. It must be sited in a coastal area with significantly different high and low tides. Tidal barrages and tidal turbines are the current dominant technologies. Barrages are commonly situated around inlets and create low-walled dams with a sluice. Turbines located at the barrage bottom turn and generate power as tides rise and fall through the grate. Another option is a free-standing tidal turbine, a large structure that floats on the water’s surface while anchored to the sea floor. These function similarly to wind turbines: As tides push against the blades, they generate electricity.
European Marine Energy Centre—Leaders in the Study of Marine Energy
Scotland is home to the European Marine Energy Centre (EMEC), the world’s first facility for testing and demonstrating marine energy converters. The centre has operated for nearly two decades and in that span of time, it has worked with 11 countries, 20 developers, and more than 35 different technologies. Its accredited Renewable Energy Testing Laboratory currently hosts two grid-connected testing sites (large technologies) and two scale test sites (small technologies).
Ainsworth, who works for the EMEC, notes that some of its projects are developed enough to start producing significant amounts of power. And that’s not all. EMEC recently became the host of a massive grid-connected project, dubbed “the world’s most powerful” turbine, which is expected to operate for the next 15 years and generate enough annual capacity to power 2,000 U.K. homes.
The Future of Marine Energy in the United States
The United States is in the beginning stages of discovering how we can harness energy from the ocean. But a recent National Renewable Energy Laboratory study shows that our coastlines hold great potential. Utilizing just one-tenth of available marine energy resources could generate enough power to meet 5.7 percent of current national electricity generation—three times as much as current installed solar capacity—and power 22 million homes. There are a few demonstration projects dotted along U.S. coasts, including a tidal project owned by Verdant Power PPA in New York. This site is currently performance testing and recently filed its first International Electrotechnical Commission renewable energy certification report.
One of the biggest impediments to further marine energy is its cost. There is lots of expensive cabling required to pull power offshore back onshore. In addition, demonstration projects are not refined enough to become utility-scale projects with a 15-year deployment. The Pacific Marine Energy Center has been working on grid-scale devices on Oregon’s west coast. Finally, more research is needed on composite materials to reduce costs and improve devices.
North Carolina, with its 12,000+ miles of coastline, numerous inlets, and flexible tidal range, is a particularly apt location for marine energy. The state is home to the Coastal Studies Institute (CSI), which hosts the North Carolina Renewable Ocean Energy Program. George Bonner, the program’s director, says its main focus is answering questions about powering the “blue economy”—e.g., How can we best use the energy the ocean provides? How can we drive down the levelized cost of energy?
CSI partners with University of North Carolina schools, the Department of Energy’s Atlantic Marine Energy Center, and other organizations to develop and test new marine energy technologies. Its North Carolina projects are currently smaller-scale initiatives like desalination and powering tiny, remote communities. However, Bonner expects grid-scale developments within the next five to 10 years. For now, Atlantic marine energy groups are working with the EMEC to earn accreditation and expand their capabilities.
There’s no doubt that marine energy is an up-and-coming renewable technology with immense untapped potential. Its expansion will diversify the grid and provide predictable energy flows as well as bring jobs, manufacturing, and energy resilience to coastal communities. As technology advances and costs continue to fall, keep an eye to the horizon—ocean power is the wave of the future.