Reflecting Wave

Off the southern coast of Australia, a new effort is under way to capture the energy embedded in ocean swells.  Special buoys will be used to convert the sea’s waves into a maximum of 62.5 megawatts (MW), or enough to power 10,000 homes, according to an announcement this week from project partners Lockheed Martin and Victorian Wave Partners Ltd. Touted as the world’s largest wave energy project, the Australia buoys are still just a drop in the bucket for wave power potential.

The constantly churning oceans that cover most of the Earth offer an inexhaustible source of clean energy. The amount of recoverable energy embedded along the continental shelf of the United States, for example, amounts to almost a third of all the electricity the country uses in one year, according to estimates from the Electric Power Research Institute,

“It’s emission-free power and it’s located close to where most of the population lives,” said Sean O’Neill, president of the Gaithersburg, M-based Ocean Renewable Energy Coalition (OREC).

But the process of harnessing all of that energy, still in its infancy, isn’t an easy one. “At this stage, putting equipment in the sea and getting it to work reliably, consistently, during severe storms, is a huge challenge,” said Aquamarine Power CEO Martin McAdam. “If anyone tells you otherwise, they haven’t done it yet.”


Stormy Waters

Scotland-based Pelamis Wave Power produces an offshore wave energy converter that looks like a colorful sea snake—and is in fact named for the species Pelamis platurus. But this snake’s bite lies in its ability to produce power.

Anchored 1.25 to 6.2 miles (2 to 10 kilometers) from shore, the Pelamis can naturally spin on a chain to face wave direction like a flag changes orientation on a flagpole. Five floating tube sections are linked by universal joints that flex in two different directions as waves roll down the machine’s serpentine length. Each joint houses cylinders that resist the wave-driven movements and pump hydraulic fluid to power onboard generators, sending electricity to shore via underwater cables. The Pelamis can handle dangerous storm swells much like a surfer paddling out to a favorite break: When big waves roll in, it simply passes through and under them.

Pelamis has produced six full-scale machines so far, each rated at 750 kW. Over the past 15 years they have logged more than 10,000 hours at sea while connected to real electrical grids, notably at the European Marine Energy Centre (EMEC), off the west coast of the Orkney mainland.

The UK energy supplier E. ON and ScottishPower Renewables each own a Pelamis machine currently in sea testing at the EMEC. Each company has ambitions to develop a wave farm, E.ON’s in waters north of EMEC and Scottish Power Renewables’ off Marwick Head in Orkney. These operations could link as many as 66 machines each and produce 50MW of power at each location. Pelamis has also partnered with Vattenfall to develop a 10MW wave farm, using up to 14 machines, off the Shetland Islands and is planning another 10MW facility off the west coast of Lewis in the Outer Hebrides. And in Aguçadoura, Portugal, past site of a three-machine Pelamis farm, Companhia da Energia Oceânica SA (CEO) might install as many as 26 machines with a target capacity of 20MW.


Orbital Marine Power is harnessing Scotland’s ocean currents for sustainable power.

“Turning the tide on climate change.” That’s the motto of Scottish tidal energy company Orbital Marine Power (formerly Scotrenewables Tidal Power).

Orbital CEO Andrew Scott is not exaggerating when he says the world’s most powerful turbine is “like nothing the world has ever seen before.”

At just over 242 feet long — about the size of a Boeing 747 — the 680-ton superstructure has two ginormous blades that slowly churn and generate power. This floating power plant, the “O2,” is estimated to generate enough energy from the fast-flowing sea currents off Scotland’s isle of Orkney to provide all the power needs of 2,000 households.

Scottish entrepreneurs seem to be at the forefront of a green industrial revolution. They are providing cutting-edge ocean power technology to drive the renewable energy needs of a new Climate Age.

Founded in 2002, Orbital is harnessing the power of the ocean to generate clean and renewable energy for Scotland and beyond. Although not in widespread use yet, tidal power has a major asset that wind and solar cannot match. It’s as predictable as a clock, providing a reliable and steady source of power forever. The total global capacity of tidal power is estimated at 120 gigawatts — roughly enough energy to power 80 million homes. And this is just the beginning.

The floating power plant can generate enough energy from the fast-flowing sea currents to provide all the power needs of 2,000 households.

We have polluted the oceans for decades, and here we have a new use.