Marine energy is harnessed from the natural movement of water, including waves, tides, and river and ocean currents. But how much power could it generate? Learn eight things to know about this abundant renewable energy resource.
Water Power Technologies Office
September 6, 2022
minute read time
Today, solar power, wind energy, and hydropower technologies are well known and common, providing clean, reliable power to communities across the United States. But there’s another clean energy resource many Americans may not be familiar with yet. Marine energy is a renewable power source that is harnessed from the natural movement of water, including waves, tides, and river and ocean currents. So could this resource soon power communities across the country? And what could that look like?
Here are the top eight things to know about marine energy:
How Is Marine Energy Captured?
Marine energy technologies transform the incredible amount of energy in the natural flow of oceans and rivers—like currents, tides, and waves—into clean electricity. Because these technologies are still developing, no single one has proven to be the most efficient or cost-effective—at least, not yet.
Fun Fact! Some devices can use changes in salt levels, temperatures, and pressure gradients to generate renewable energy.
What Are the Different Kinds of Marine Energy?
Water can heave up and down, surge back and forth, and even swirl in circles. Energy can also be captured by harnessing the temperature difference between ocean surface waters and deep ocean waters or the pressure created when fresh and salt water mix.
Marine energy developers are building a diverse fleet of machines to harness this power. From paddles that sway like beaver tails to rippling sea snakes, marine energy devices come in many shapes and sizes. Some sit on the water’s surface, some hover just above the sea floor, and others spin like mini underwater wind turbines.
How Much Power Could Marine Energy Generate?
The opportunities to harness marine energy are abundant. The total available marine energy resource in the United States is equivalent to approximately 57% of all U.S. power generation in 2019. Even if only a small portion of this technical resource potential is captured, marine energy technologies would make significant contributions to U.S. energy needs.
Some locations carry huge amounts of potential power. Alaska’s Cook Inlet possesses one of the greatest tidal energy resources on Earth with currents that can stream in and out at 9 miles per hour. The inlet is capable of providing enough energy to power 7.5 million homes. Alaska could soon be a marine energy powerhouse, and many U.S. coastal communities have abundant marine energy resources flowing nearby.
What Is Marine Energy Used For?
In the short term, marine energy could serve U.S. coastal communities and provide local, affordable, and clean power to rural and remote island communities, which often rely on expensive shipments of fossil fuels. For example, Eastport, Maine, comprises scattered island communities, which could get power from the Atlantic Ocean’s immense tidal energy rushing past their shores.
Marine energy technologies can also power offshore work and the blue economy. These technologies could help observe the ocean to predict destructive storms (like nor’easters and hurricanes), measure ocean health, provide clean water in disaster relief scenarios, and power food- and water-production systems.
In the longer term, marine energy can also play a big role in decarbonizing the country’s power grid.
What is the Marine Energy Industry Doing to Protect the Environment?
The U.S. Department of Energy’s Water Power Technologies Office (WPTO) is funding research to learn how to responsibly deploy marine energy devices so they can coexist with wildlife and their ecosystems. For example, the Triton Initiative, led by Pacific Northwest National Laboratory, tested underwater acoustic camera technology to evaluate fish interactions around deployed marine energy devices in Alaska and New Hampshire. By collecting as much data as possible on interactions, noise, and other potential changes to natural environmental conditions, WPTO is ensuring that environmental safety is a top priority for the marine energy industry.
What Are the Benefits of Marine Energy?
Abundant, predictable, and clean marine energy could serve as a valuable complement to other renewable energy resources. When the sun sets and winds slow, oceans and rivers keep powering on, filling any energy gaps.
Plus, if bad weather or natural disasters disrupt electricity and water supplies, marine energy systems can potentially kick in to help provide both. This flexible delivery of energy could provide power to remote, coastal, and island areas and help make communities more resilient to crises, including the effects of climate change.
Why Hasn’t Marine Energy Progressed as far as Solar, Wind, and Hydropower?
Marine energy can be a challenging resource to harness. Salt water and sediment could damage ocean-bound machines; waves can crash with incredibly strong force; and deploying or servicing devices offshore can be costly—in terms of time and money.
That’s why WPTO supports the critical research and development that could help the marine energy industry reduce costs and create tough, robust machines and, in so doing, help marine energy advance toward commercialization.
What Does the Future of Marine Energy Look Like?
It’s an exciting time in the marine energy industry. While challenges remain—including high costs, lengthy permitting and licensing processes, and barriers to testing (because there are few facilities that can accurately evaluate devices both on land and offshore)—companies are successfully deploying prototypes, offering a peek into what this industry could look like.
The PacWave South test facility, which is currently under construction, will be the first accredited, grid-connected, pre-permitted, open-water wave energy test facility in the United States. It will provide a valuable offshore test site for marine energy developers to evaluate their devices in a real-world environment.
Marine energy is reliable, widely available, and ready to be harnessed. With support from WPTO, this abundant renewable energy resource could soon bring power to coastal communities, remote islands, offshore industries, and the evolving U.S. power grid.
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