Can Blue Energy Boost US Transition to Net Zero?

The USA has an excellent and untapped resource in marine energy, according to 2021 NREL report: Marine Energy in the United States: An Overview of Opportunities.

“While marine energy technologies are still at the relatively early stages of development, the resource potential is immense and distributed widely across the nation’s coastlines and rivers.”

The report calculates the total energy available in the 50 states is 2,300 TWh/yr, equivalent to 57% of the electricity generated by those states in 2019. Obviously the technology could only harness a fraction of that, but it is still a significant amount of untapped green power potential. Capturing just 10% of the available energy, with a capacity factor of 30-70% would be 5.7% of the country’s electricity production, or 40-90 GW per year. Tidal energy resources are particularly concentrated on the West Coast and Alaska, while the ocean currents of the Gulf Stream could be harnessed to provide Florida, Georgia, and North and South Carolina with power. In addition the overseas territories like Hawaii have immense potential for blue energy. Marine energy is particularly useful as it is often predictable, which would be very advantageous in balancing other, more intermittent renewable energy sources.

Around the world, marine energy is being researched, but development is slow and expensive. Partly this stems from technical difficulties: the maintenance of systems deployed on the surface of the sea or underwater is going to be costly. Many of the best resources are in out-of-the-way locations, which means that long-distance transmission lines will have to be built to bring the energy to where it is needed. So, while many different prototypes have been tested, there is no commercial size array functioning anywhere. This is disappointing, but also an opportunity: whichever nation develops viable commercial marine energy is likely to reap huge benefits.

The USA has been slow in moving forward in developing projects. Other countries, including the UK, France, Chile, and China, have been building small-scale pilot schemes for years. In June this year, The U.S. Department of Energy’s (DOE) Water Power Technologies Office (WPTO)  announced $1.215 million for 23 projects to further marine energy research and development at DOE’s national laboratories. These projects will advance marine energy technologies and their roles in achieving both national and local clean energy goals.

Additionally DOE has just approved $2.4 million in funding for twelve new Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) marine energy research and development projects.

These include:

Aegis Technology will develop a tidal turbine system to supply power to off-grid electric vehicle and electric project charging stations. If successful, this project will be the first tidal energy-powered charging station of its kind in the United States.

Integral Consulting Inc.’s Rapidly Deployable Hardware Software Network for WEC Site Characterization and Monitoring This is a low-cost, user-friendly, rapidly deployable hardware and software network for wave energy site characterization, wave climate impact monitoring, and environmental monitoring, so that sites can be identified and assessed quickly and at a low cost.

Ocean Renewable Power Company (Portland, ME), Power for Subsea Networks: Ocean Renewable Power Company, Inc. will develop marine renewable energy technologies appropriate for powering subsea sensor networks and other systems, providing a power supply for instruments deployed in the ocean and further enabling long-term sensing missions.

This is a fairly small amount of funding for relatively unambitious schemes, but it is better than nothing. Some other functioning pilot projects include:

CalWave Power Technologies

CalWave successfully commissioned its CalWave x1 off the coast of San Diego in September 2021. This event marks the beginning of California’s first at-sea, long-duration wave energy pilot operating fully submerged – being tested for six months with the goal of validating the performance and reliability of the system in open ocean. Their ocean wave generator functions underwater, thus avoiding the buffeting of storms, which is a real challenge for surface-based systems.

ORPC’s RivGen

ORPC’s RivGen unit installed at the remote village of Igiugig, Alaska, became the longest operating riverine hydrokinetic energy device in the Americas. ORPC is building its successful core technology with the intention of offering large scale units to customers, including utilities.

Verdant Power

In October 2020, Verdant Power deployed three of its fifth-generation turbines on a single mounting in New York City’s East River – a tidal strait. This one-half scale demonstration project has exceeded expectations and generated 210 MWh in the first six months of continuous operation, a record for marine energy production in the United States. Most importantly, the turbines performed at over 99% availability and established a water-to-wire efficiency, including all losses, of 46%.

Overall, the US has huge potential for sea and river-based energy generation. It will be expensive, at first, as all new technologies are, but blue energy is an untapped resource and could be an important part of the transition to a renewables-powered energy system.