Wave and tidal power has the potential to contribute significant amounts to the overall energy mix, according to the Electric Power Research Institute which carried out extensive research and published their findings in a report called Mapping and Assessment of the United States Ocean Wave Energy Resource.

The UK government says the country potentially could get as much as 75 per cent of its energy needs from the waves and tides combined. The US Department of Energy estimates that wave power in the US could generate as much 1,170 terawatt-hours per year-this is equivalent to more than one-quarter of all US electricity consumption.

Development is slow

While the industry is making some progress, experts say that this development remains decades behind other forms of renewables as it still requires massive funding and significant amounts of research. It will certainly take some time to catch up to solar and wind power development.

Very few commercial-scale wave power operations exist, although a small-scale installation did operate off the coast of Portugal in 2008 and 2009.

In February, US corporate giant Lockheed Martin announced a joint venture to create the world’s biggest wave energy project-a 62.5-megawatt installation slated for the coast of Australia that would produce enough power for 10,000 homes.

Scotland, surrounded by the turbulent waters of the Atlantic and the North Sea, has become the focus of intense wave-energy research and development. The government has also approved a 40-megawatt wave energy installation in the Shetland Islands.

Complexity of wave power

However, the complexity of harnessing wave power remains a huge challenge. This has seen a number of designs come about such as writhing snake-like attenuators, bobbing buoys, even devices mounted discreetly on the ocean floor that operate by exploiting differences in pressure as a wave moves by.

Some devices generate the electricity on the spot and transmit it via undersea cables to shore, while others pass the mechanical energy of the wave along to land before turning it into electrical energy.

Despite all of these innovations, there isn’t a single winning concept as experts continue to search for a better way to harness this natural power. This is according to Robert Thresher, a researcher at the National Renewable Energy Laboratory, who says that we have yet to invent the best device.

Wave energy is where wind energy was three decades ago. At that time, engineers had not yet discovered the best design for wind turbines. However, decades of research has left us with some seriously sophisticated turbine designs. With wave power, some research took place after the Arab oil embargo of the 1970s, but since then government and commercial research and development into wave power has been sluggish compared to wind and solar energy.

Expensive and complex

From a technical point of view, operating in the ocean is far more challenging than on land. Building offshore wind installations, for instance, is normally more expensive than constructing wind farms onshore. In addition, saltwater is a hostile environment for devices since the waves present numerous challenges for energy capturing.  While this provides attractive opportunities for energy capture, creating an optimum design is a major challenge within itself.

George Hagerman, a research associate in the Virginia Tech University’s Advanced Research Institute, explains that cost issues, unreliable and inefficient designs, as well as wave energy itself can pose numerous challenges.

So far, the wave energy field is filled with small companies picking off small quantities of government funding where possible. Participation from large companies like General Electric and Siemens is needed to boost wave power funding and development. It is possible that large companies are waiting for the technology to be developed before investments are made. This is a common problem in any developing field.

Don’t limit the technologies

So far, projects producing only a handful of megawatts are being installed. For this reason, experts recommend that the industry keeps developing and deploying different technologies. By doing this, they will eventually discover which design works best.

The process to refine those technologies is ongoing. In recognition of this, the European Marine Energy Centre in Scotland’s Orkney Islands allows companies to connect their devices to existing infrastructure and cabling to test their electricity-generating capabilities and identify issues.

Too many variables to compare

Jason Busch, executive director of the Oregon Wave Energy Trust — a non-profit group dedicated to helping advance the industry, says that there are too many variables, such as the price of natural gas or eventual passage of a carbon tax, to apply the experience of wind or solar power to a different technology and time period.

But, he says that despite challenges, the steady technical progress will eventually lead to substantial amounts of grid-connected wave power by 2035. He adds, “In the course of 10 years we have gone from having zero wave energy technologies that are even remotely viable to having several in the water, and on the cusp of commercial viability. We’re making some really good progress.”

Further reading

Electric Power Research Institute-Mapping and Assessment of the United States Ocean Wave Energy Resource [pdf]

Yale Environment 360-Why Wave Power Has Lagged  Far Behind as Energy Source