Riding Energy’s Next Wave

New worldwide companies are being formed in a quest to learn how to capture the power of oceans and seas.

Wave power is the transport of energy by ocean surface waves, and the capture of that energy to do useful work – for example, for electricity generation, water desalination, or the pumping of water into reservoirs, according to Wikipedia.

The world’s first commercial wave energy farm was launched in 2008 three miles off the north coast of Portugal. Agucadoura Wave Park consists of three devises which can each produce 750 kilowatt hours of power. While this state-of-the-art wave farm may be considered a novelty for now, we at WMB don’t think that will be the case for long.

Waves are the result of wind blowing over the surface of the ocean. In many areas of the world, the wind blows with consistency and enough force to provide continuous waves. There is considerable energy in ocean waves. In turn, wave power devices extract energy directly from the surface motion of ocean waves or from pressure fluctuations below the surface.

About 70 percent of the earth is covered with water, and this water is the largest single repository of solar energy. One only need watch waves crashing into a rocky shore to appreciate the potential energy and force that is produced.

If just 2 percent of the ocean’s energy were converted to electricity, it would meet the entire world's power needs, according to the Northwest National Marine Renewable Energy Center in Washington state.

Even better, waves are predictable unlike solar power; this makes grid requirement more practical. Since greater numbers of people are living within 50 miles of oceans, power would not need to be transported long distances.

Wave energy has lagged solar and wind energy development mainly because of technical reasons. But now many of these problems have been solved. Oceans can be unforgiving, hostile and difficult to control, and salt water is corrosive. Creating devices that can withstand these conditions has been a challenge for years.

Most government money and private and industrial development were instead funneled to solar and wind power development. Big oil and gas companies have in recent years devised technologies adaptable to deeper and rougher waters. Even the BP oil disaster has taught engineers how to better understand deep water currents and waves.

Wave energy, more so than tidal energy, offers readily accessible ocean power. Tidal energy uses the currents in the sea, and wave energy draws power from the rise and fall of waves on the surface.

The Electric Power Research Institute, with offices and laboratories in California, North Carolina and Tennessee, conservatively estimates wave energy could provide about 6 percent of America’s electric needs, while tidal power could produce another 3 percent. To put this into perspective, hydroelectric power currently produces 6 percent of our power.

Wave devices come in a variety of designs, but all work to transform energy from the rolling motion of waves of water to electricity. Usually the aquatic motion is converted into mechanical energy that runs a turbine or generator.

Machines used in Portugal were designed by Pelamis Wave Power Co. of Scotland. Worldwide, there about 100 competing designs for wave and tidal converters. But as this industry matures, it will be necessary to weed out designs that are either too costly or inefficient.

Other designs include Aquamarine Power's Oyster and perhaps the most unusual wave energy converter, the Anaconda.
Developed by Great Britain’s Checkmate Seaenergy for use in deeper waters about 5 miles from shore, the Anaconda is a long sealed tube filled with water. It is attached to the seabed and pointed at incoming waves.

As each wave rolls over the tube, it creates and pushes a growing bulge within the length of the tube and builds pressure that operates a turbine at the other end. Such a devise may be 23 feet in diameter and 600 feet in length, and capable of generating 1 MW of power. The devise is constructed of a type of rubber and can survive years of use in seawater.

Costs for marine power are high but may drop rapidly as capacity and demand grow. Manufacturers predict this technology will produce power at 5 cents to 10 cents per kilowatt hour. But marine energy will need government support in the early stages, just like solar and wind-turbine. Wave energy is currently eligible for a 1.1 cent per kwh tax credit.

Pelamis officials say, “No new energy is competitive right out of the box,’’ but they claim that each doubling of capacity could bring down costs by 15 to 20 percent.

At WMB, we think government incentives could encourage private investors to back these new marine technologies because they help ensure the likelihood of return on investment.

K.P. Yue, a professor of ocean engineering at MIT, says, “It’s not ready for prime time – it needs about five to 10 years of development. But it could have a huge impact in 20 years.”

This post is by TechMan, WMB co-author who blogs about trends, issues and ideas affecting business, industry, technology and consumers.