Ocean Renewable Power Company, a Maine-based marine energy organization, has developed an underwater turbine tidal device called the TidGen Power System. Similar in shape to an old-fashioned push lawn mower, a single moving piece on the device generates energy from the ebbs and flows of the tides. The device floats underwater, affixed to the ocean floor via two cables.
The company tested one of these tidal devices in Maine’s Cobscook Bay last summer. A similar tidal device could be deployed for demonstration and research purposes in Cook Inlet off the coast of Nikiski as early as this summer.
Nathan Johnson is the vice president of development at Ocean Renewable Power Company. He says Cook Inlet is the country’s largest tidal energy resource.
“In tidal energy, once you understand the site, once you understand the technology, you can predict the amount of energy that can be produced with a very high level of confidence for 100 years into the future,” Johnson said.
Johnson says the company has already conducted studies on the feasibility of the site, which is located near the East Foreland Lighthouse Reserve. He says existing infrastructure for oil and gas operations in Nikiski can help advance marine projects in Cook Inlet.
The company has also studied the potential environmental impacts of these tidal devices.
Johnson says they’ve conducted fish monitoring on Alaska’s Kvichak River on the Alaska Peninsula, where similar devices have been deployed. According to Ocean Renewable Power Company’s website, more than 100 million sockeye salmon smolts and 10 million sockeye salmon adults have passed by their turbines with no observed injuries or mortalities. Johnson says the turbines also spin at a slow rate with no open tip, and that salmon typically avoid the area underwater where the tidal devices would be placed.
The company is also looking into the amount of noise the tidal devices produce. Johnson says the noise level is below the ambient noise level underwater and is inaudible to most marine mammals.
“That doesn’t mean there’s no risk, but we’ve been able to really try to quantify that risk and indicate that it’s extremely low,” he said.
According to the Department of Energy, the potential tidal devices in Cook Inlet are expected to produce up to five megawatts of power, which could power up to an estimated 1,200 homes. Tim Ramsey is the program manager for the department’s green energy program. He says the energy industry is ready for a large-scale showcase of its tidal technologies.
“Marine energy is really harmonious with the local environment," Ramsey said. "It can be deployed at a local level, on a small scale. It can be deployed right there where the energy is needed.”
If implemented on a larger scale, Ramsey says tidal devices in Cook Inlet could provide opportunities for job growth. He says between the state’s wave and tidal energy potential, Alaska has the capacity to generate 27% of the electricity the country needs.
“In the state of Alaska where the energy dynamics are changing, to look at how energy-rich Cook Inlet is and how there’s existing infrastructure in place, I think the importance is it provides a much more resilient grid into the future,” Johnson said.
According to the National Renewable Energy Laboratory, Cook Inlet is estimated to hold as much as 18 gigawatts of tidal energy potential. This is more than 20 times the amount of energy used by all road-connected communities in Alaska.
“There’s always been buzz in Alaska about the tidal energy potential in Cook Inlet, but to see it so close and within grasp, I think is exciting for people, and we certainly share that sentiment as well,” Johnson said.
The first phase in the Department of Energy’s investment will be a ten-month feasibility study at the Cook Inlet site, along with another tidal project site in Washington state. The department will then decide which project to move forward with.
