Tidal energy could help decarbonize Alaska’s Railbelt by 2035, study shows

Tidal energy could contribute to decarbonizing Alaska’s Railbelt by 2035 and facilitate the production of clean fuels like hydrogen, growing the state’s economy, a recent U.S. study has shown.

The April 2024 study was led by researchers from the National Renewable Energy Laboratory (NREL), with support from the U.S. Department of Energy’s (DOE’s) Water Power Technologies Office (WPTO).

The study is said to quantify “for the first time” the role that tidal energy could play in Alaska’s power grid, the Railbelt. Cook Inlet, abundant in tidal energy resources, connects directly to the Railbelt grid, serving 75% of Alaska’s population, including Fairbanks and Anchorage, WPTO noted. 

To address the challenges of assessing the exact energy potential of tidal systems, NREL researchers collaborated with the Homer Electric Association, a utility that operates a portion of the Railbelt grid near Cook Inlet, to evaluate Cook Inlet’s tidal energy resources accurately.  The NREL researchers developed a power systems model using theoretical and real-world data to estimate potential energy contributions to the Railbelt grid by 2035. 

The findings indicate a “big potential’’, showing that the current Railbelt grid could support up to 200 MW of tidal energy, enough to power at least half of Anchorage’s 115,000 homes. After planned upgrades, the grid could handle up to 300 MW, nearly enough to power the entire city. 

However, the generated power isn’t the only benefit, because, according to the study, tidal energy could also reduce the grid’s carbon emissions by up to 37%.  

Cook Inlet’s technical resource potential is estimated at 80 TWh per year, exceeding the Railbelt’s current electricity consumption of 5.2 TWh per year. This “excess” energy could be used to produce clean fuels like hydrogen or ammonia for use in Alaska or export overseas.

The estimates rely on tidal energy technologies reaching commercial viability by 2035. According to the study, if the technologies are ready by that date, tidal energy could meet about 14% of the Railbelt’s electrical demand by 2035, potentially increasing to 20% when Railbelt upgrades are completed.

“Tidal energy systems capture power through the movement of water as tides go in and out. Tides are uniquely predictable—with accuracy to the nearest inch over a decade in the future—meaning this resource could help balance other sources of renewable energy on the power grid,” said WPTO.

In February, the U.S. DOE selected two marine energy projects to receive $6 million for the development of a tidal energy research, development, and demonstration pilot site. One of those projects, ORPC, aims to deploy two tidal energy devices in Cook Inlet.

These devices are intended to demonstrate the feasibility of tidal energy projects in Cook Inlet, which is said to be the largest tidal energy resource in the U.S. The devices are expected to produce between 1 MW and 5 MW of power.