- Annual wave power potential in terawatt-hours/year for U.S. coastal regions
- Fishermen view commercial wave energy as a threat
- Catching the waves – Ocean power
Annual wave power potential in terawatt-hours/year for coastal regions
CREDIT: Lorena Villa Parkman
DATA: Mapping and Assessment of the United States Ocean Wave Energy Resource; Electric Power Research Institute
Fishermen view commercial wave energy as a threat
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Catching the waves – Ocean´s power
CORVALLIS, Ore. – The power of the oceans promises a massive untapped reservoir of sustainable energy for coastal U.S. states such as Oregon – and for island nations such as the Philippines or Guam.
The first commercial test wave buoy to produce electrical power is scheduled for installation off the coast of Reedsport, Ore., this fall.
Ten will be deployed in all, creating a 1.5 megawatt wave energy hub that can power about 1,000 homes.
Utilities and researchers expect to learn a lot about what it takes to harness the waves from this phase.
Oregon State University and the University of Washington are partnering to develop wave energy through the Northwest National Marine Renewable Energy Center in Corvallis, Ore., to support wave energy development throughout the United States. Investigations focus on the technical, environmental and social aspects of wave energy.
Waves are among the largest marine energy resources in the ocean. The Department of Energy estimates that there is enough power in the ocean waves to provide up to 2 terawatts of electricity, doubling the world’s current generating capacity for electricity.
Two recently released assessments – Mapping and Assessment of the U.S. Ocean Wave Energy Resource and Assessment of Energy Production Potential from Tidal Streams in the U.S., demonstrate that waves off the nation’s coasts could provide 15 percent of the United States’ total energy needs by 2030.
The U.S. uses about 4,000 terawatt-hours of electricity per year. Most people pay their electric bill based on the number of kilowatt-hours of electricity they use. A kilowatt-hour provides enough power to light up 10 100-watt bulbs for an hour. A terawatt-hour measures up to 1 billion kilowatt-hours.
Wave power is widely accessible compared to other renewable sources. The Northwest National Marine Renewable Center and several other organizations in Oregon are trying to make the best use of ocean’s power.
“If you do a Google search on how much power we can get from waves, the answer will be about 10 percent of the world’s energy,” said Belinda Batten, director of NNMREC. “If you think this is just one ocean energy technology, this is somewhat significant.”
While testing and research move forward to harvest ocean waves, Oregon´s first test buoy for a wave energy plant will be anchored in Reedsport this fall.
“There are lots of reasons why Oregon is a good option for wave energy”, said Sarah Henkel, assistant professor at OSU and researcher at the Hatfield Marine Science Center, in Newport.
“The ocean here is very energetic and we have a very straight coastline with no barrier islands. Forecasting the waves is more reliable, buoys deployed 200 miles away can measure the waves that we will get to the coast 48 hours later,” she said.
Think about it. If you are a utility company trying to manage a portfolio with different alternative energy sources, having a reliable measure of the amount of energy you will be able to receive from a certain type of technology is very valuable. “The predictability and the magnitude of the waves make them a great resource from an energy perspective,” said Henkel.
On the West Coast, the summer months generate less powerful waves than during the turbulent winter. Meteorologists can gage a specific wave climate 48 hours out. That means a utility company can count on a reliable estimate of power supply.
Another reason Oregon is an ideal testing ground is that the state has unused electrical infrastructure dating back to the peak of logging industry.
“Electricity was run to the coast to support the mills shipping logs out. There aren’t that many logging operations anymore and that infrastructure is unused,” said Henkel. “There is an opportunity to take energy from the coast to send it back to the rest of the state and the West Coast, that´s attractive to developers since they can save money on initial investments.”
Waves will always be best on the West Coast, though, according to Batten. That’s wave energy 101. “They are created by winds and they blow from west to east, so that’s why. Also, waves are stronger the farther you are from the equator,” she said.
From the ocean to our homes
OSU isn’t involved in deploying the buoys this summer or in creating actual wave energy. But large-scale research to accelerate the future of wave energy is well underway.
“We don’t build buoys that collect energy, but buoys that can analyze energy collection,” Henkel said. “Buoy developers will anchor theirs to our analysis buoy and plug it in. Researchers then will analyze the quantity and quality of energy that it makes under different wave scenarios.”
The buoys or wave energy conversion devices, once they are tested and approved by utility companies, will go into the ocean and will connect via cables beneath the ocean floor to the electrical grid to get the energy from the device to the shore. There’s talk about having power pods on the ocean floor to connect several buoys, functioning like a power strip, Henkel said.
Many kinds of devices are under development and no single technology has been proven superior to another one, according to Northwest National Marine Renewable Energy Center.
All of them would require cables under the ocean’s floor to transmit the power to the grid on the shore.
Currently, four main types of WEC devices generate or convert energy from waves.
•Oscillating water column: Generates power when waves push against a horizontally hinged flap or when they are funneled into a structure that causes a water column to rise and fall.
•Attenuator: This device is oriented in the direction of incoming waves that cause articulated components to bend and drive generators. Attenuators are typically moored to the ocean floor on one end.
•Overtopping: This converter has a partially submerged structure that funnels wave over the top of the structure into a reservoir. The water runs back to the sea powering a hydropower turbine.
•Point Absorbers: These devices capture energy from the “up and down” motion of the waves. They might be fully or partially submerged.
“If anybody claims that their device is better, it’s a false claim,” Batten said. “We will start testing them in the ocean in September 2012 and until you get them into the ocean you don’t know what changes they can produce.”
The project’s technology challenges are associated not only with electrical generation and output, but mechanical systems, anchoring, reliability, predictability and integration of the power into the electrical grid.
Most of the experts involved in developing wave energy in Oregon agree that development of this energy source is still very much in the early stages, with lots of unknowns.
“We still don’t know what the WEC devices do, their environmental impact,” Batten said.
Batten mentioned that one thing slowing down development now is funding. In the United Kingdom, there has been a surge of investments at a regional and national level, in comparison.
Challenges come from all sides: technical, regulatory, financial. But, in fact, the U.S. is not very far behind the rest of the world. “We are abnormally slow in general,” Henkel said. “There are testing facilities in Portugal and Scotland that have tested devices, but they are not at a scale of commercial development yet either.”
The truth is that every form of development, whether it’s a renewable energy facility, church, road or fossil fuel plant, displaces species. “They kill birds, pollutes the air, it does stuff, all forms of human development affect the environment in some way,” said Busch.
“However, with ocean energy those impacts are extremely low, and they are by far lesser than fossil fuels’ impacts. Compared to other sources of renewable energy, wave energy also has a very low impact.”