A Juneau inventor wants to bring ocean energy to your sockets

Inventor Lance McMullan has a beautiful home on Douglas Island. But he spends almost all his time in the garage.

On one side of the room there is camping equipment, a set of winter tires and a small couch. On the other, a huge 3D printer and dozens of boxes and garbage bags filled with pieces of bright yellow plastic.

He reached into one of the bags and pulled out a cracked, triangular fin.

“Every part failed at some point,” McMullan said. “I just sit in this room and work for a few days.”

All this time and discarded plastic are a testament to the device hanging on a rope in the middle of the room – an elegant tube with a large rotor at one end. It turns powerful ocean currents into renewable electricity.

“Everyone who has met me in the last 14 years has only heard about it. That’s all I can think about,” McMullan said. “I can’t look at the moon without thinking about the next tidal cycle.”

McMullan isn’t the only one excited. Tidal energy could be an alternative to burning fossil fuels such as diesel and natural gas, which cause human-caused climate change.

The prospect of harnessing ocean energy has generated a lot of buzz and a lot of federal money in Alaska. Particularly in Cook Inlet, where proposed large-scale tidal projects could eventually power thousands of homes.

McMullan starts smaller. His company, Sitkana, makes small tidal generators that are ideal for individual fishing boats and houseboats. He hopes they can revolutionize ocean energy in the same way that roof panels revolutionized solar energy.

“It’s just a tremendous amount of power that you can’t touch,” McMullan said. “I almost feel like I have an obligation to make this a reality.”

Finding a niche for tidal energy

Alaska has long been considered an ideal location for harnessing tidal energy. Steep fjords and coves along the coast enhance the natural rise and fall of the tides. When water flows into these channels, it concentrates into a strong current that is ideal for generating electricity.

“It’s hard to go anywhere in Alaska without stumbling upon a good tidal energy site,” said Brian Polagye, a professor of mechanical engineering at the University of Washington and director of the U.S. Department of Energy’s Pacific Northwest Laboratory.

Because water is so dense, ocean energy can be more powerful than wind energy. And because tides are constant and predictable, energy from them can be more reliable than solar energy, which varies with weather and seasons.

But it is much less popular. This is mainly because it costs a lot more.

“If tidal power were the cheapest form of energy, it would be as ubiquitous as solar panels,” Polagye said.

Standardized designs and mass production of parts have dramatically lowered the costs of solar and wind energy technologies over time. So when a tidal project tries to take advantage of a large network such as a railway right-of-way, it must compete with much cheaper alternatives.

But Polagye says tidal energy can succeed by exploiting unique niches in the market. In Alaska, this may mean building in remote locations where the network is weaker.

He points to the village of Igiugig, which is experimenting with a similar electricity-generating turbine using electricity from the Kvichak River.

“The turbine there is really the best source of power. It competes with imported diesel fuel,” Polagye said. “The fact that it’s more expensive than other online sources doesn’t matter if you don’t have a network.”

Sitkana tidal turbines may be best suited to diesel-dependent coastal communities such as Angoon, Hoonah and Kake in southeast Alaska, where energy prices are much higher than in the Lower 48.

Solar and hydropower have been explored in these places, but large utility projects take a lot of time and money to build. As communities adopt solutions such as electric vehicles and electric heat pumps to reduce carbon emissions, the demand for renewable energy continues to grow.

Experts say decarbonization will likely require a mix of renewable energy sources. McMullan believes the mix should take tidal energy into account.

Chinook 3.0

His efforts to make ocean energy accessible began while he was working as a sailor on a troll in Sitka. From the back of the boat, he watched the hooks bob in the water and imagined a tidal generator that could be towed this way.

“It was this summer that I started sketching out the designs,” McMullan said. “But I realized I had no idea what they were or if I could get them to work. I knew nothing about fluids or mechanical engineering.

So he went back to school to study engineering, then spent time as a maintenance technician building wind turbines in the Lower 48 before returning to Alaska.

It took him years to develop Sitkana’s current prototype, the Chinook 3.0. The small tidal turbine has several key differences from other tidal generating structures.

While many tidal designs are anchored to the ocean floor, the Chinook 3.0 is a free-floating and portable device. It weighs just under a hundred pounds.

“He swims through the water like a fish,” McMullan said. “And installing them is no different than dropping an anchor.”

The Chinook 3.0 can be attached to a small crane or pulley at the back of the boat and then lowered as the tide rises or falls.

Tidal currents spin a rotor that turns a generator inside the turbine body, producing 1.6 kilowatts of electricity. This is enough for the daily needs of one person, assuming the generator remains in the water for most of the day.

So a family may need multiple generators. However, the energy cost of just over $1,000 per kilowatt hour is relatively low – comparable to the price of wind power. This is largely due to the Chinook 3.0’s plastic construction.

Using plastics can also be a solution to maintenance issues, which is another common obstacle with tidal energy. Powerful ocean currents and corrosive seawater adversely affect tidal turbines. Continuous repairs can disrupt power and pose challenges for communities that may not have the knowledge or manpower to keep turbines running. So Sitkana plans to let the ocean do its worst.

“What we are doing is accepting that they will be destroyed,” McMullan said.

When a generator breaks down, they will pull it out, replace it, and recycle the plastic from the broken device.

McMullan will soon ship the Chinook 3.0 prototype across the country to a tidal research facility in Cape Cod, Massachusetts. There, they will monitor the turbine in the water to see how fish and other wildlife respond to it.

“But we are very close. This is where it works,” McMullan said. “Now it’s just about scaling it, getting it to market and generating power.”

Sitkana expects the generators to hit the market next year for about $2,000 each.