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Cold Water Energy
Ocean Thermal Power
Unlimited energy. Fast-growing fruit. Free air-conditioning. John Craven says we can have it all by tapping the icy waters of the deep.
The topic under discussion is Craven's plan to use cold water pumped up from the deep ocean to provide low-cost and environmentally sustainable power, water, and food to a new residential and commercial development in the Marianas, a chain of islands some 3,000 miles to the west.
John Craven Credentials:
A PhD in ocean engineering, a law degree, and a stint as chief scientist for the US Navy's Special Projects Office. There he was instrumental in developing the Polaris missile program, the submarine-based backbone of America's nuclear deterrence and one of the most complex defense systems ever. In fact, most deep-ocean activities - saturation diving, exploring with submersibles, searching for tiny objects on the ocean floor - owe their origins to top secret, cold war-era Navy projects in which Craven had a hand.
A polymath who is as comfortable talking about the Law of the Sea as he is the plumbing nightmares inherent when 200 men a day urinate in a submarine, Craven is hard to keep up with. His mind darts from why the Navy should make subs out of glass to the sad end of his long telephone friendship with the late Marlon Brando to the remarkable prodigiousness of his small experimental Hawaiian vineyard. "One week the plants have no leaves," he says, "the next they just go zing, zing, zing and are full of fruit!"
The grapes are a key part of his plan, through his Common Heritage Corporation, to build communities around the world sustained by deep-ocean water, starting on the Mariana island of Saipan. And he's not doing it just out of the goodness of his heart. "I fully intend for CHC to be a multibillion-dollar corporation," Craven says.
His grand plan could come across as a bar-stool fantasy, but it's already won $75 million from Alpha Pacific, a Memphis, Tennessee, venture capital firm, and $1.5 million in federal funds. Craven hopes that within a year, bulldozers will begin clearing land on Saipan and engineers will start sinking a pipe to pump icy water from the ocean depths to produce electricity and freshwater. And back in Kona, Craven expects to use cold-water agriculture to transform five acres of otherwise barren lava fields into the world's most productive vineyard. "The economics are absurd," he boasts. "Once we prove the technology on Saipan, imagine what it could do for places like Haiti!"
Craven's system exploits the dramatic temperature difference between ocean water below 3,000 feet - perpetually just above freezing - and the much warmer water and air above it. That temperature gap can be harnessed to create a nearly unlimited supply of energy. Although the scientific concepts behind cold-water energy have been around for decades, Craven made them real when he founded the state-funded Natural Energy Laboratory of Hawaii in 1974 on Keahole Point, near Kona. Under Craven, the lab developed the process of using cold deep-ocean water and hot surface water to produce electricity. By the 1980s the Natural Energy Lab's demonstration plant was generating net power, the world's first through so-called ocean thermal energy conversion.
"The potential of OTEC is great," says Joseph Huang, a senior scientist for the National Oceanic Atmospheric Administration and an expert on the process. "The oceans are the biggest solar collector on Earth, and there's enough energy in them to supply a thousand times the world's needs. If you want to depend on nature, the oceans are the only energy source big enough to tap."
Stephen Oney, vice president of Ocean Engineering and Energy Systems in Honolulu, which will design CHC's Saipan pipes, agrees: "The technology is there, and the science is there. It just needs to be improved." Oney, who recently inked a deal with the Pentagon to build an OTEC power plant for a US naval base on the Indian Ocean island of Diego Garcia, envisions a day when floating OTEC platforms produce enough hydrogen to meet all of the world's energy needs.
Craven likes the way they think, but he believes there are simpler, cheaper, and more immediate applications of cold-water technology. He favors building systems in ideal locations, such as islands adjacent to deep water with no continental shelf. Sink a big pipe, crank a pump, and - voila! - you've entered a world powered by ocean water. Once primed, the pipe acts like a giant siphon, requiring relatively little energy to keep an inexhaustible supply of cold at hand. Already, 39-degree-Fahrenheit water courses through the Natural Energy Lab's newest pipe - a 55-inch-diameter, 9,000-foot-long polyethylene behemoth - at the rate of 27,000 gallons a minute, 24 hours a day.
Running the frigid pipes through heat exchangers produces unlimited air-conditioning that costs almost nothing. Draining their sweat yields an endless supply of freshwater for drinking and irrigation. The cold water also creates a temperature difference between root and fruit that Craven believes speeds growth. And by turning the flow on and off, Craven has found he can further accelerate the plants' growth cycle by forcing them in and out of dormancy - he can get three crops of grapes a year and pineapples in eight months instead of the usual 18. Feeding some of the water through a contraption Craven calls a hurricane tower generates clean electricity. "What the world doesn't understand," says Craven, still zig-zagging through the parking lot, "is that what we don't have enough of is cold, not heat."
A day later, the sun feels like a giant piece of red-hot charcoal overhead as Craven unlocks the gates to his small demonstration garden at the Natural Energy Lab. In tow are a handful of CHC's technical partners and managers escorting the lieutenant governor around the garden. The black lava ground is hard and hot, but behind the chain-link fence, Craven has created a little oasis: a 10- by 20-foot rectangle of lush lawn, a closely cropped putting green, a 10-foot-square "soccer field," flower gardens, an orchid patch, and rows of grapes. A wooden structure that Craven calls the skytower holds what resembles a radiator of sweating PVC pipes dripping steadily into a tub, providing freshwater for drinking, washing, and irrigation.
CHC's success depends on two projects that expand on Craven's ideas: a vineyard in Kona to grow table grapes for local restaurants, and a more complex, much larger-scale version of his oasis, on Saipan. A stable US territory, the island is a booming destination for Japanese tourists. Tokyo is just two and a half hours away by air. And the Marianas offer generous tax deals to Japanese who retire there. But Saipan has a limited supply of freshwater and must import, at great expense, all of its food and oil. On the northern end of the island, CHC plans to sink a 24-inch-diameter pipe and build a hundred-acre development featuring 100 townhouses, a golf course, soccer fields, and even an athletic complex where Japanese sports teams can train. Like a cross between an industrial park landlord and a public utility, CHC will supply electrical power (generated by a mix of ocean water, sun, and biomass), freshwater, and air-conditioning, as well as its cold-water agriculture tech to tenants and farmers of specialty crops. It will also sell freshwater to hotels that now rely on expensive reverse osmosis desalination
.
Caught under the glare of Craven's brainpower, it all seems doable. "John Craven is a visionary," says Sylvia Earle, former director of NOAA and a CHC board member. "He's effectively demonstrated his pilot approach on a small scale, and who knows where it will lead? Who could have guessed how Henry Ford's auto design would change the world? Craven is not always right, but he's always worth listening to."
Craven has no doubts. On the grapes and freshwater alone, he says, "we'll make a fortune. We'll make freshwater for nothing, 13,000 to 15,000 pounds of grapes per acre per year, three times what the best vineyard in California can do." If the numbers pan out, Craven says, CHC will pay off its investors in seven years.
As the official tour winds on, Craven drags a plastic chair to the middle of the lawn, plunks himself down, and resumes talking about his anti-aging experiments. Investigating the osmotic and thermodynamic properties of plants led him to wonder about the human body, and now he's hooked. "I've patented my cold-water therapy, and I want to open a cold-water health spa right there," he says, pointing to the rocky coast. "The doctors don't agree with me, but that's because innovation is the enemy of the status quo - it puts people out of business."
Craven flexes his limber ankles and smiles. It won't be long before we know whether he's unleashed a new wave of octogenarian marathon runners or stepped off the deep end at last.
The key to Craven's cool world is converting the ocean's thermal energy. The first step: Sink a pipe at least 3,000 feet deep and start pumping up seawater. The end result: an environmentally sustainable, virtually inexhaustible supply of electricity, freshwater for drinking and irrigation, even air-conditioning. Here's how it works:
Refrigeration: Cold seawater circulates through a closed loop of pipes that replace the coolant and compressor found in conventional air-conditioning units.
Irrigation:
Pipes carrying cold water run beneath fields of crops, sweating freshwater to irrigate plants and chilling their roots, promoting faster crop cycles.
Desalination:
Cold seawater passes through Craven's "skytowers," which contain closely packed radiator-like networks of pipes. The frigid pipes sweat in the tropical heat, producing freshwater condensate.
Power Generation:
Pipes draw warm water from the ocean surface and cold water from the seabed. The warm water enters a vacuum chamber and is evaporated into steam that drives an electricity-producing turbine. The cold water condenses the steam back into water for drinking and irrigation.
Silverbeard |
Latest page update: made by Silverbeard
, Oct 2 2007, 4:52 AM EDT
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