Oceans Hold Huge Power Potential, Challenge is Harnessing It

Since 1844, when the first tide wheel was built, inventors have been trying to harness the immense power of the ocean with little success. Now the next generation of engineers is trying to break the course of history and turn this niche industry into a major energy player.

In 1894, currents were used to compress air and run a turbine; today, waves are being used to compress air in an oscillating water column. In 1923, a patent was issued for a snake-like machine that used waves to run a hydraulic pump; today, Pelamis Wave Power has deployed (and since removed) an almost-identical machine off the coast of Portugal. in 1946, a horizontal-axis turbine was invented to harness the currents of the ocean; today, Verdant Power is testing a similar device in the East River near New York City.

“Many people think this industry is new, but these devices have been around for a long time. You see a lot of the newer designs that are based on older designs,” says Rob Cinq Mars, President of the engineering consultancy Free Flow Energy.

The marine energy industry is generally broken up into a number of different technologies: wave, tidal, current, salinity gradient, ocean thermal and offshore wind. Offshore wind — while still very nascent — is one of the only technologies being deployed on a commercial scale.

There's a lot of excitement about wave and tidal technologies today — a result of the broader interest in clean energy. But Cinq Mars is cautious about some of the claims being made by companies. Many tout the benefits of their technologies, but few are actually close to achieving those claims.

“Show me the energy,” he says. “Not a lot of these devices are actually generating electricity today.”

The small bits of electricity actually being generated usually come in at the 40 cents per kilowatt-hour range.

Wave power anaconda Technological successes in marine energy over the last 165 years have been incremental. But with the emergence of new materials, sophisticated electronics and unprecedented amounts of money being invested in new ocean energy technologies, the industry is looking far different than it did in the past. In fact, says Richard Meyer, president of the Ocean Energy Council, it has changed more in the last few years than it has over the last century.

“Two or three years ago ... it was really only small laboratory testing of devices. These days they've got things in the water, they've got sites selected and they're worrying about regulations. Things have really come a long way in a short time,” says Meyer.

Today’s marine renewable energy industry is commonly compared to the wind industry of the 1980's and early 1990's. At that time, there were many competing technologies being developed and thousands of turbines were broken during the testing process, says Meyer. Eventually, certain designs won out, parts for those machines were standardized, and a supply chain was created to service them.

The marine energy industry will have to go through the same culling process.

“We won't break thousands [of turbines] but it may be a lot before we get somewhere. Ocean energy is about 15 years behind wind energy, but it won't take 15 years to catch up,” he says.

With only 10 megawatts of installed marine energy capacity around the world, the industry has a long way to go before it catches up with the more than 120 gigawatts of global wind capacity.

In theory, the oceans could supply us with a lot of energy. The International Energy Agency estimates that tidal, wave, current, salinity gradient and ocean thermal technologies could represent more than 100,000 terawatt-hours of energy each year.

There remain a number of difficulties that companies must face in order to bring the industry to this scale.