The wave of the future?
Researchers are developing devices to harness the power of the ocean, and the Gulf of Mexico is the hotbed of activity
By KRISTEN HAYS
Copyright 2007 Houston Chronicle
GALVESTON — Hurricane Humberto was a pleasant surprise to at least one energy executive visiting the Texas Gulf Coast.
The mid-September storm that rapidly grew into a Category 1 hurricane shortly before coming ashore in High Island brought 20-foot waves and winds exceeding 50 mph.
The unexpected surge in strength gave a Minnesota company's ocean-wave energy device, being tested off the coast of Galveston, its first bout with bad weather.
"It was pounded for hours, but the storm didn't crush or flip it," said Mark Thomas, CEO of Independent Natural Resources, a small private start-up in landlocked Minneapolis suburbia. "We're comfortable with its resiliency."
The device, dubbed the Seadog, is designed to capture ocean-wave energy from swells or waves to pump seawater into storage tanks. The water then could flow through hydroelectric turbines to provide energy.
Land-based systems do the same thing by moving water through turbines from one reservoir to another at a different elevation. But unlike land systems, an ocean-based system can rely on wave rhythm to move the water.
The Seadog has few moving parts and requires only wave motion to move its pump up and down. That means more energy captured from waves can be converted to electricity, rather than subverting some of it to power the device itself, Thomas said.
An array of the devices also could move large volumes of seawater to desalination plants for conversion to fresh water, without burning fuel or electricity to drive pumps, Thomas said.
Last week a team of professors and researchers from the marine engineering technology department at Texas A&M University at Galveston wrapped up a three-month test of an 8,000-pound steel model of the Seadog in about 15 feet of water off Galveston's shore. Thomas said their findings will be released in two to four weeks.
Frank Warnakulasuriya, assistant head of the department, said the test team will provide an independent assessment of the device's efficiency and effectiveness as an energy harvester. The team isn't studying how it would be used for generating electricity.
Not 'imminent technology'
Houston startups also are testing different wave-energy devices off Galveston. Swell Fuel has a horseshoe-shaped device anchored to the ocean floor and designed to generate electricity through wave movement. MyChoice Utilities has tested an underwater turbine under the Pelican Island Bridge.
MyChoice CEO Daniel Romero said he hopes to tap into Galveston's power grid if tests are successful, though the cost remains an unknown.
The quest to turn ocean waves into energy is an emerging technology that is "basically where wind was 20 years ago or more," said Pearce Hammond, an alternative-energy analyst with Simmons & Company International.
Hammond said the technology has promise in the alternative-energy realm.
But ocean-wave energy lags behind more established technologies like wind, solar and geothermal — energy derived from the Earth's interior heat.
"If you're a utility and you need to get megawatts to the grid, you're probably not going to go that route now," he said. "I'm not pessimistic. It has a lot of potential, but it's not an imminent technology and we can't rely on it right this moment."
The World Energy Council's 2007 survey of energy resources says that while many wave-energy devices are in that research stage, some designs have been tested or deployed off the shores of Scotland, Australia, Portugal and Wales.
They include Edinburgh, Scotland-based Ocean Power Delivery's Pelamis wave-energy converter, comprising a series of loosely moored cylindrical hollow steel segments connected by hinged joints.
As the segments move with waves, hydraulic cylinders in the joints pump oil through hydraulic motors, which in turn drive generators to produce electricity.
Pelamis segments look like long pipes floating on the water, while the Seadog resembles a miniature offshore drilling rig.
The Pelamis cylinders are moored, while the Seadog is fixed to the ocean floor. But the Seadog could be moored if outfitted for deeper waters, Thomas said.
Roger Bedard, ocean energy leader for the Electric Power Research Institute in Palo Alto, Calif., said the Pelamis is in place to be the first commercial wave-energy power producer. Its first units recently were commissioned in the Portugal parish of Aguçadoura, where it is slated eventually to power up to 15,000 homes through a privately funded utility.
But harnessing energy from waves has yet to be done on a mass scale. Bedard noted that ocean energy was a popular concept along with wind and solar in the aftermath of the 1973 oil embargo imposed by the Organization of the Petroleum Exporting Countries. The onshore renewables stayed on track, while ocean energy fell back.
"That's primarily because it operates in a hostile, remote environment, and you just don't go there first. You go to the easy places first — the windy and sunny places on land," he said.
Consistent movement
Thomas is betting on waves because they're more consistent than wind, which sometimes doesn't blow, and the sun, which doesn't shine in one place all the time.
While one Seadog won't be all that powerful, a farm of the pumps could generate hundreds of megawatts or more, Thomas said. The higher the waves, the more energy is captured.
He said he and his team chose to test the device off the Texas Gulf Coast because people are used to seeing oil and gas structures from the beach — a sharp contrast to the East and West coast where activity is strictly limited.
"You guys are used to stuff in the Gulf. In California, if you can see anything off the coastline, it diminishes the tourism value — at least that's the mind-set," Thomas said. "We ran into that issue in California, so we said, 'OK, we'll do the Gulf.' "
kristen.hays@chron.com
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