Technology News - January 8, 2004

Creating electricity with undammed hydropower

One of the first field tests of a truly renewable approach to producing electricity from river currents is set for mid-2004 in a river north of Boston. Alexander Gorlov designed the “no head” turbine at Northeastern University. It is only one of many proposed devices in development that could extract power from water with minimal environmental damage, but this patented prototype has gained international interest, several partners, and “hard-to-get” funding to move the technology beyond just laboratory tests. Thanks to collaboration with Verdant Power, GCK Technology, and a half-million-dollar grant from the Massachusetts Renewable Energy Trust (MRET), the upcoming test will collect important data by evaluating the Gorlov turbines as part of an integrated system that converts free-water flow into electricity.

Gorlov’s interest in developing a technology that extracts power from water without destroying the environment dates back to 1958–1960, when he helped design Egypt’s Aswan Dam. “Hydropower has developed a very bad reputation [and] not because of the turbines, but because of the dams,” explains Gorlov. He is an emeritus mechanical engineering professor and director of the Hydro-Pneumatic Power Laboratory at Northeastern University in Boston and chief technology officer for GCK Technology in San Antonio, Texas. Gorlov’s triple-helical turbine design does not require a dam and has spun successfully in tests conducted in water bodies around the globe over the past several years.

Generating hydropower with conventional turbines requires pressure created by dams. But building dams disrupts the natural environment, including fish migration, so any new large-scale conventional hydropower is not considered “green”, according to Carol Werner, executive director of the Environmental and Energy Study Institute (EESI), a nonprofit organization. However, she says that EESI promotes technologies like the Gorlov turbine that can capture energy from the flow of water without dams because fish can swim around the turbines. The Gorlov turbines can work in shallower waters better than conventional turbines, so this technology can bring hydropower to places dams couldn’t go, says Trey Taylor. He is president and head of marketing development for Verdant Power, the independent hydropower systems integrator in Virginia that is partnering with Gorlov and GCK Technology. And in terms of renewable energy, water currents are much more dependable than solar or wind, he adds, which may explain why the number of similar designs he is aware of has grown to 38 from 6 just two years ago.

The demonstration project in the Merrimack River is important for the hydropower industry because it will demonstrate the full integration of the turbine, generator, and distribution system, something we usually don’t see in early field tests, says Michael Bahleda, Area Manager for Hydro, Renewables, and Economics for the Electric Power Research Institute, a nonprofit energy research consortium. Usually, if a turbine even gets to demonstration, most tests are strictly for spinning and mechanics, he adds.

Gorlov started developing his turbine in 1993, and Northeastern patented it in 1994. GCK Technology holds the exclusive license, and Verdant is one of three companies with contracts to use the turbines in field demonstrations. He chose the helical design because it is “immune” to the direction of the water flow and the axis can be set up vertically or horizontally depending on water depth. Gorlov says that the plan is to install six twin triple-helix turbines in a vertical, side-by-side arrangement in the Merrimack River estuary tidal streams. This coated aluminum turbine is 1 meter (m) in diameter (diam) and 2.5 m in length. Each twin turbine will sit in its own cage attached to a barge underwater. A similar helical turbine design has spun in South Korean waters since March 2002, and generated some electricity.

Over the years, Gorlov managed to find research support from the U.S. Department of Energy (DOE), the U.S. Navy, the National Science Foundation, and the New England Power Co. But getting federal funding in the United States has been difficult because there isn’t much money for renewable energy. In fact, DOE’s National Renewable Energy Laboratory does not research hydroelectric power technologies. The funds being used to test the turbine in the Merrimack River come from the MRET state fund, which is one of 17 funds in 12 states totaling $3.5 billion. These state funds are generally collected with a small surcharge on utility bills to support development of renewable and clean energy.

We looked for projects that were well past the blueprint stage but hadn’t received too much commercial testing, that did well in peer review, and showed promise for the local area, says Chris Kealey, a spokesperson for the Massachusetts Technology Collaborative, the organization that administers MRET grants. Verdant will contribute an additional $300,000 to the Merrimack demonstration.

Gorlov says that in the Merrimack demonstration, “turbines represent just a part of the system.” Here, GCK Technology and collaborators at Verdant are working out the details related to system installation and operation, such as securing the apparatus in the water, harmonizing the turbines with electric generators, and connecting everything to the local power grid. Gorlov says it could take a few years to make this technology a widespread reality.

Even though the power output from the Gorlov turbine is small, because of the slow speed and low torque, at least it can extract some power from otherwise unproductive sites, says James Sysko, a hydropower consultant in Bethel, Maine. His attempt to power a small hotel with Gorlov turbines has been a challenge. But he is optimistic that capitalizing on many little sites could equal the size of a large dammed area, without the environmental impacts.

GCK Technology and Verdant share this vision of the turbines as a substantial source of renewable distributed power. “The concept behind [these] turbines is that as you put in a number of them, you start to build a whole field,” says Taylor. The Merrimack River flows at about 3 knots, so he expects the demonstration project to yield 20 kilowatts (kW). On the basis of studying the size of the river, the river’s capacity will max out at 500 kW. Other locations in the United States and around the world—including ocean currents—could generate much more power. For example, Gorlov estimates that the Uldolmok Strait in South Korea, which flows at 12 knots, could generate hundreds of megawatts of capacity from tidal currents.

Once these turbines are successfully integrated with generators, Gorlov and Taylor have various ideas on how to expand their use. The turbines could be part of modular systems that float on catamarans in remote locations. Hydropower generation could be packaged with water purification, desalination, or hydrogen production or be hybridized with solar and wind power options. Before all that will be possible, however, they need a cost-efficient product that works consistently. The best way to keep production costs down right now is to standardize basic equipment, says Taylor.

Gorlov says that he “receives dozens of inquiries from around the world on a day-[to]-day basis” regarding possibilities for these turbines. In addition to U.S. projects in Massachusetts, Maine, and Long Island, New York, a 2.2-m-diam stainless steel Gorlov helical turbine commissioned by the Korean Ocean Research and Development Institute will be installed there during the summer of 2004. In addition, other small field research projects are under way in Brazil’s Amazon River and coming soon to Ireland. —RACHEL PETKEWICH