A Memphis man with curiosity and a high school degree has invented something that could help save the world from global warming.
Improbable, yes, but the chairman of the University of Memphis' mechanical engineering department isn't laughing. He's done the math on Geoff Greene's machine for harvesting the power of ocean currents.
"It needs to get some large-scale testing," Dr. John Hochstein said, "but I think it has potential to be very successful."
It's a water turbine, but different than existing technology that has yet to succeed commercially in converting the force of sea currents into pollution-free electricity.
"We're not aware of anyone else trying this approach right now," officials with the Department of Energy's Hydropower Technologies Program stated in a written response to The Commercial Appeal.
Typical turbines are like underwater windmills. Their blades must knife through the water fast enough to spin the turbine to produce electricity. The performance deteriorates when barnacles attach to the blades, slowing them down. They are also expensive to maintain.
Greene's water turbine is a different animal.
He uses the force of falling water inside the blades to turn the turbine, which is sealed in the middle of the structure.
Picture a bicycle wheel. At the top of each hollow spoke is a tank of water contained within the tire.
As the wheel turns and a tank reaches the top, gravity sends the water gushing down the spoke to the center of the wheel.
The torrent of water within this closed system continuously spins the turbine.
Greene's valve system re-circulates the water from one tank to the next.
A 100-foot or 250-foot-diameter wheel slowly turned by an ocean current would be too powerful for typical gearing needed to convert the power into fast-spinning turbine. Too much torque, too much stress.
But Greene's idea is "a unique way of getting power from the flowing fluid (the ocean current) to the electrical generation device," Hochstein said. "It's not the usual gear box and transmission shaft. A different kind of scheme. It avoids some mechanical power transmission problems."
Greene approached the U of M engineers last year about doing the calculations.
Hochstein, 56, was reluctant before finally taking a look.
"I've been around the block a few times," he said
Hochstein reviewed the design on his own time and without charge to Greene. He likens Greene to do-it-yourself car mechanics, calling him a "shade-tree inventor."
"The first time he came to my door, I thought he was nuts," Hochstein said. "I said forget it, that's just ridiculous. He's persistent. He said, 'Why don't you run some numbers?' "
Hochstein relented and did the calculations. "My thinking changed," he said.
He concluded the invention is "plausible, doesn't violate any engineering principles. A very clever idea for overcoming some problems with those devices."
Department of Energy
There are more than 100 "device concepts" intended to make renewable electricity by harnessing the energy of waves, currents, tides or free-flowing rivers, according to officials with the Department of Energy's Hydropower Technologies Program, but very few are ready to operate.
Two major hurdles face the evolving technology: Cost competitiveness and regulatory/institutional challenges, according to a written response provided to The Commercial Appeal by program officials.
Emerging technologies "must develop systems that can survive the harsh marine environment while reliably producing renewable electricity at a rate that is competitive with other traditional options," program officials stated.
Greene believes his concept answers the call. Lacking a gear system, the simpler design has fewer moving parts to break.
And it can be large enough to produce what he calls "base loads" of electricity 24 hours a day, seven days a week.
A 100-foot wheel makes 1.8 million watts, he said.
The shop
Greene has a workshop behind his mother's house just off Lamar.
Inside are various inventions in various stages of development.
A device he has made for making wrought-iron fences that easily conform to the ground's contour.
An oval bicycle sprocket he has created that makes pedaling more efficient.
A steering wheel he has fashioned for backhoes, so operators can control the heavy equipment with just one hand.
And there's a nine-foot-tall spinning wheel made of half-inch plastic pipes, with eight spokes and water jugs affixed at the outside end of each spoke. This is Greene's model for the water turbine.
Nearby is his "hydro-channel." It looks like a long fish tank. He flips a switch to pump a water current through the tank. The water spins a small set of blades, anchored by cables.
With the real water turbine, cables will keep the structure from rising to the top. The blades, made of light concrete, will actually float, Greene said.
The real thing may be 100 feet in diameter to start, and subsequent ones as large as 250 feet.
"If you double the size, you quadruple the power," said Hochstein. "In this case, bigger is a lot better."
The larger the wheel is, the more workable the invention is, said Greg Maxted, a mechanical engineer who has a business and teaches at Southwest Tennessee Community College. He also looked at Greene's work and pronounced it "very, very novel."
"I think it's workable in a large-scale factor. ... I would love to see a working model and see if he can work out the bugs and what kind of output he can get," Maxted said.
Near disaster
Greene, 45, is a 1982 graduate of Sheffield High. He credits his late father for teaching him about mechanics and leverage. "I just had a knack," he said.
Greene owned a moving company for 10 years before he became ill with celiac disease, which causes fatigue.
He started using his head more than his muscles.
But it was a near disaster some years ago on the Mississippi that focused his attention on the power of water currents.
He, his dad and father-in-law cruised down to Tunica in a 25-foot Bayliner Saratoga to see where Splash Casino was being built.
To illustrate how deep the river was, Greene dropped anchor with its 100-foot rope.
About the time he ran out of line the anchor snagged. The river's current caused the rope to pull down on the back of the 3,000-pound boat with tremendous force. The vessel came within four inches of taking on water before Greene's father cut the rope.
The water's power, Greene said, "caught my interest."
What's next
"We need to put a 30-foot wheel in the (Mississippi) river" to test the turbine, Greene said.
He figures $50,000 from investors would fund the model.
"This is not just about money. I need the right people interested to contact me who want to work on it," Greene said. "Need management, personnel people. The entire thing needs to run as a business."
The Memphis-based venture capital company Innova took a look.
"On the technology side, it looked interesting," president Ken Woody said. "I was impressed Dr. Hochstein seemed to think it looked workable. ... Alternative energy is really a hot topic."
But negotiations ended early when Greene and Innova couldn't agree on who would own the patent, Greene or a company owned mostly by others.
While he continued talking last week to other potential investors, the Department of Energy announced some good news this month.
It intends to soon solicit applications for funding projects like Greene's.
The Department of Energy's investments "will accelerate the technological evolution of the leading designs, with the goal of deploying the best systems by 2015," officials stated.
http://www.commercialappeal.com/news/2010/mar/21/inventor-finds-right-spin-on-turbine/
