Sees Viable Energy in Ocean Waves

Having studied the potential for wave energy on California’s coast, Asfaw Beyene likes what he sees. ” Asking if there is energy that can be extracted from waves is like asking if it is hot in Las Vegas in the summer,” he muses. “It’s just a matter of quantifying it and analyzing how we can put that to good use.”

As a professor in the Department of Mechanical Engineering at San Diego State University in San Diego, California, Beyene makes a specialty of studying cutting-edge energy sources such as this. He researches renewable energy in addition to the energy efficiency and environmental impact of various power sources.

In 2002, the California Energy Commission funded the Feasibility Study of Wave Energy Conversion for the coast of California. Beyene and his team assembled a database of wave characteristics and identified key factors in the development of wave energy. They mapped the entire coast using data based on 50 years of wave profiles and concluded the energy content ranged from 10 kilowatts per meter of wave front to 30 or 40. “This is a highly concentrated form of energy. You don’t get that much from one meter of wind or solar. With that much concentration, there is a lot of energy,” Beyene reports.

Several types of wave energy mechanisms have been developed, but the team didn’t delve into specific technologies and recommend one over the other. Generally, two basic types exist, one consisting of a turbine that produces rotary motion and the other a pneumatic piston in a reciprocating motion, each driven by waves to turn a generator. Each technology has its advantages, and no preferred method has emerged for all situations. According to Beyene, “Conditions vary from place to place. You may have high waves and high wavelength with low frequency in one region and high frequency but low wave height in another.”

“It’s very exciting,” Beyene says of the project. “Even more so because there aren’t many individuals or institutions who have done that research. We kind of broke the ground.” They have published the results of their California wave study in many refereed journals. And several students have shown interest, doing their master’s work in it. They hope to get continued funding so they can build small prototypes and compare technologies, but the California Energy Commission hasn’t decided what to do next.

Coming from Ethiopia, Beyene, 58, went to the Warsaw University of Technology in Poland for his B.S., M.S., and Ph.D. degrees, having received a scholarship there. He got his degrees in mechanical engineering and specialized in aerospace and power engineering. He concentrates in the thermal side of aerospace, meaning jet engines and gas turbines. After college, he worked briefly at the University of Aachen in Germany before he joined the faculty of SDSU in 1989. He came there because many aerospace companies populated California. “I thought it would be a good opportunity to grow professionally.”

But in the early 1990s, Beyene found it hard to get funding for research in the aerospace industry, as the Cold War was winding down. “Jet engines produce power. Now what do use that power for?” he asks rhetorically. “Whether it is for flying or producing electricity, in terms of modeling and analysis, it is a very simple transition. So I converted that jet engine focus to power and electricity and energy.”

He further explains his career change: “There were two ways to research saving energy. One is to use more efficient systems, and the other is to convert existing fossil-fuel-based energy systems to renewable energy. So my strategy became to focus on those two aspects. Once I got into the field of energy with graduate students and colleagues here, I drifted more and more into exotic areas such as wave energy.”

One of Beyene’s specialties became combined heat and power (CHP) systems, which involve recovering waste heat and putting it to good use. He says, “I go to wherever the waste heat is and try to see how I can use that. The most appropriate use is in industry for process heating, to produce hot water or steam. The waste heat can be used to produce power.”

Going a step further, considerable attention has been paid recently to combined cooling, heating, and power (CCHP). “I do some small and not yet thoroughly tested systems such as taking waste heat from an automobile engine and using that to produce chilled water,” Beyene reports. “As you can imagine, this may have a lot of potential in the transportation industry where they need large cooling systems.” He adds, “In the high-temperature, high-grade heat, there is no challenge, but the main difficulty is when you go to low-grade heat, which is low temperature. In that range, we have systems we are in the process of assembling. We go very low, even hopefully below 20 degrees F., and we try to produce power from that waste heat.”

When it comes to wave energy, the most lucrative areas of the world include the coasts of Scotland, Canada, Africa, and Australia and the northwestern coast of the United States. Beyene points out that the northern coast of California has more than the southern coast, and Oregon and Washington have even higher potential with higher waves. This is true for the eastern U.S. coast and also for Europe. He adds that Islands, like those off southern California, dissipate wave energy.

Where does the United States stand in developing wave energy generation? “We are lagging in terms of research and funding. We’re way behind Europe. They have already built wave energy converters in many parts -- Portugal, Spain, northern U.K.,” Beyene says. “Many other countries, including China and Japan, are already doing extensive wave energy conversion research, and they have much more advanced research than North America.”

In addressing how to spur research in the U.S., Beyene comments, “There is a policy problem in developing wave energy. One aspect is just a popular image thing. People imagine this bulky, ugly thing down on the beach. That is the wrong perception. But mainly, it is the bureaucracy. You need to have permits from so many agencies that I can’t imagine how to break that. But that tends to relax greatly when we face an energy crisis because in general, the politics for energy has always been reactive, not proactive. The technology is there. The Department of Energy and California Energy Commission have not shown enough interest in wave energy conversion.”

By now you get the idea that Beyene thinks wave energy has potential. “I don’t have any doubt that wave energy will beat solar and may be competitive with wind.” He doesn’t consider it a fair comparison, though, because wind and solar have years of research behind them. He notes that wave energy is close kin to wind energy, as they both derive from the sun, and he sees opportunities for combining wave energy and offshore wind energy generation, noting the proliferation of such wind projects in recent years. “We can use oil platforms, the very old ones. For example, those around Santa Barbara can be used for wind energy conversion, and that can be coupled with wave energy conversion.”

Beyene goes even further by saying that wave energy generation devices don’t necessarily have to produce electricity. “We can, for example, produce hydrogen offshore. Hydrogen is explosive, and people don’t like it close to their homes or in cities, so you can produce hydrogen in these offshore stations and then bring it ashore for use.”

However, Beyene knows a scenario for developing such technologies may not come for awhile, the election of Barack Obama notwithstanding. “Projects like that need institutional support at a bigger level, meaning there has to be research funding. That has not been forthcoming, so I continue to focus on my other research areas such as energy efficiency on the thermal side.” But he remains ready and eager to get back into studying wave energy as a component of our national energy portfolio. “If we get an opportunity to get funding, we will definitely pursue it again.”