Water comprises 70 percent of the earth's surface and contains enormous potential as a source of energy in the future. The Amazon River alone, which transports more water than any other, could generate enough electricity to power all the towns and villages along its shore. The same is true of other great rivers around the world. So why aren't we tapping more from water's pulse?
That's the aim of Alexander Gorlov, a professor of mechanical engineering at Northeastern University in Boston, who is trying to launch an idea that would harness the power of currents and tides. If his deceptively simple-looking prototype - a barrel-shaped 36-by-40-inch turbine - can successfully transform the awesome forces of oceans, rivers, and bays into electricity, it could radically change hydropower. And thus, it could potentially solve the
world's energy problems, says the optimistic Dr. Gorlov.
Today's forms of hydropower account for much of the 7 percent of world electrical output not generated by fossil fuels. Although hydropower is a clean and unlimited source of energy, it often comes at a high price. It is currently dominated by models that require huge, expensive dams - which can displace people, flood vast areas, and wipe out fish populations that need open rivers to spawn. In fact, it was Gorlov's experience with the Aswan Dam in Egypt, which he helped design and construct, that convinced him that these large-scale projects were not the best answer to hydropower generation.
Holding back further use of hydropower has been the lack of an efficient, inexpensive, and environmentally friendly device to extract energy from water - not to mention the competitively low costs of coal and oil. But the current energy crisis - with rolling blackouts in California and rising fuel prices - might be enough to boost America's appetite for renewable energy. And, Gorlov hopes, for his turbine.
Gorlov's helical turbine is based on the so-called Darrieus turbine, developed for windmills in the 1930s. The original never proved practical. The design, with its straight airfoil blades, was efficient but unstable, tending to break easily because of extreme vibrations. When Gorlov tested it in flowing water, however, he found it worked better than any other turbine, although it still had vibration problems.
After laboratory testing, he found that twisting the blades into the shape of a helix, like a molecule of DNA, would solve the problem. In flowing water, the Gorlov turbine captures 35 percent of the water's energy, compared with 23 percent for a straight Darrieus turbine and 20 percent for a conventional turbine.
That may not seem like a huge improvement, but "in this business it's a lot, because [the turbines] operate all the time, and after a while, the advantages really build up," says Jim Sysko, resident engineer at Gould Academy, and owner of Small Hydro East, in Bethel, Maine. And unlike other turbines, Gorlov's device works well regardless of the direction of water flow, making it practical in tidal flows as well as rivers.
In a tidal pool in Vinalhaven, Maine, Mr. Sysko is currently testing Gorlov's turbine which is expected to pump 5 kilowatts of energy into the Maine grid starting this fall. That's not much, but it will be enough to power the 14-bedroom motel directly above it. If the prototype proves successful, Sysko plans to install more turbines along the Maine coast.
Another test installation is now in operation in a remote area of the Amazon River in Brazil. There, local residents, who are far from the nearest power lines, use the turbines to recharge dozens of car batteries to run their television sets.
Gorlov also envisions huge underwater "power farms" that could create electricity from hundreds or even thousands of the devices linked to each other in a grid, which is anchored under water.
In full production, the cost of an installed open-river hydropower system of his turbines, Gorlov says, should be $400 to $600 per kilowatt - less than the cost of constructing other power-generation systems. And that's before operating costs of fossil-fuel plants are taken into account.
But Gorlov's turbines have other advantages, proponents say: When they generate electricity, you can't see them, you can't hear them, and they're virtually disruption-free.
"A Gorlov turbine could be airlifted into a remote community which is located near a river," says Peter Rodenbush, a multi-system consultant in Boston. "If you put the turbine in the river, it gives the community the chance to generate enough power to meet many of its current needs, as well as generate more power to increase income."
"Because this is a product that will be used in remote locations, it's extremely important that it ... be reliable," says Ed Kurth of Texas-based GCK Technology, a renewable-energy firm that secured worldwide rights to the patents from Northeastern University in February. "The design we'll have for mass production will be aluminum. And we plan to have a design that can be put together with common tools, so you can install it in remote locations."
But Joseph Ignazio, president of Helical Turbine of Massachusetts, in Cambridge, who was the first to officially test Gorlov's turbine, in 1996 in the Cape Cod Canal, foresees several challenges.
The first is storage. While the turbine can be hooked up to an electric grid, the energy that doesn't get immediately used is wasted. And unlike a gallon of gasoline, for example, there's no way to harness the energy for later use.
Adding to this storage problem is the way nature itself works. This issue was raised by Livingston Taylor, a visiting fellow at Harvard University, during a recent conference at Northeastern about the Gorlov turbine.
"Right now the Mississippi River is running very strong," Mr. Taylor told the conference. "But how many people here have seen it in September, when ... the current has slowed to almost nothing. What happens in that situation to something like the Gorlov turbine?"
Gorlov's long-term solution is to use the turbines to break down seawater into hydrogen and oxygen through electrolysis, storing hydrogen in pressurized vessels offshore. The stored hydrogen could then run through a generator to make electricity - just as a gasoline or diesel generator would.
While the technology for producing hydrogen through electrolysis exists, it is far from a system that could produce hydrogen on a large scale.
"I think it's a fantastic idea," says Sysko. "But even if there was a crash program, it would probably take us at least 10 years to get there."
Mr. Rodenbush says the storage problem can be easily solved, however, if one looks at what he considers the real problem of the energy crisis: the way the electric grid works.
"Right now, the big thing about energy is there's a difference between what is generated in one place and what is demanded in another, and the grid is what transfers that energy," he says. "When a power-generating plant makes too much energy for the demand, a whole lot of it leaks out in terms of heat in transformers and all kinds of things. When there's too great a demand, people get brownouts.
"There's no reason why the grid can't be provided with these decentralized generators, like the one Jim Sysko is using in Maine. There could be millions of them powering the system, reducing the demand for more natural gas and fossil fuels, which is the whole issue," he says.
Another problem, Mr. Ignazio says, is funding. Renewable-energy development has always played second fiddle to oil, coal, and nuclear energy. And last month, President Bush proposed cutting the national budget for renewable-energy research by a third.
"We need federal subsidization," says Ignazio. "With the airplane industry, if it weren't for the federal subsidies, we'd never be able to fly like we fly today."
Yet despite problems like storage and funding, interest in Gorlov's invention continues to grow. The South Korean government recently asked Gorlov to design an arrangement of turbines for the narrow Uldolmok channel that separates the peninsula from an island. Gorlov came up with a system that could produce more than 80 megawatts - enough to power 80,000 houses - without disrupting the channel's extensive shipping. Representatives of the government met with Gorlov last month to review the plans, which they expect to include in next year's national budget. "A big plus to the turbine is that it doesn't need a dam," Ignazio says.
"There are 55,000 sluiceways [artificial channels into which water is let by a sluice] in the US where these turbines could be put to use now," says Rodenbush. "Remember, we've got this concentrated version of energy that just flows by us every day. Nature doesn't waste anything."
(c) Copyright 2001. The Christian Science Monitor