What works for wind power could also work un­der the sea

A wind-power pioneer wants to tap the oceans for en­ergy “We’re try­ing to cre­ate a ma­jor en­ergy re­source from the oceans”

Bloomberg Businessweek (Asia) - - NEWS - Ellen Huet

Jim Dehlsen, a 79-year-old winden­ergy pioneer who sold one tur­bine company to En­ron and took an­other public, has spent his life think­ing about the best way to make blades turn in the sky. For his lat­est ef­fort, he’s flip­ping a tur­bine up­side down and plung­ing it hun­dreds of me­ters deep in the ocean. There, marine cur­rents ro­tate the 27-me­ter long blades to pull power from the sea.

Aquan­tis, Dehlsen’s Santa Bar­bara, Calif., company, will start de­ploy­ing tur­bines in 2018 in wa­ters near Wales and the Isle of Wight. Its most am­bi­tious pro­ject is a 200-megawatt field of marine tur­bines in the strong Gulf Stream off the coast of Florida, due to come on­line in 2019 or 2020. The world’s oceans re­main rel­a­tively un­tapped as an en­ergy source, com­pared with wind and so­lar. By 2030, Dehlsen says, marine en­ergy could serve 8 per­cent or 9 per­cent of U.S. power needs. “The oceans are the ma­jor re­main­ing po­ten­tial for re­new­able en­ergy,” he says. “Get­ting on that now is re­ally ur­gent.”

It took wind at least 15 years to be­come a vi­able, cost-ef­fec­tive re­source. In the late 1970s, when sci­en­tists first started ex­per­i­ment­ing with wind tur­bines, “peo­ple laughed at you and said, ‘Wind will never work,’ ” says Robert Thresher, a re­search fel­low at the National Re­new­able En­ergy Lab­o­ra­tory in Golden, Colo. In the ’80s and ’90s, the in­dus­try set­tled on the three-blade tur­bine design con­sid­ered the stan­dard to­day. Many as­pects of tur­bine design can be ap­plied to the oceans, ad­justed to han­dle the slower, heftier fluid dy­nam­ics of sea­wa­ter.

Aquan­tis is de­vel­op­ing sys­tems to cap­ture en­ergy from waves, from tidal cur­rents, which switch di­rec­tion twice a day, and from gyre, or steady, cur­rents. Much of Dehlsen’s ob­ses­sion these days is with the Gulf Stream. Its con­stant cur­rent can ro­tate tur­bines day and night, al­low­ing Aquan­tis to squeeze more power out of each tur­bine. That will cut the price per kilo­watt-hour. “Be­cause the stream flows all the time, it’s prob­a­bly the one that can be­come cost-ef­fec­tive most eas­ily,” Thresher says.

Aquan­tis, which isn’t the first company to design un­der­wa­ter tur­bines, wants to lower the cost of marine en­ergy. Dehlsen says de­ploy­ing an Aquan­tis de­vice— tow­ing it out to sea, fill­ing it with sea­wa­ter bal­last, then an­chor­ing it—runs about $347,000 per tur­bine. The ro­tor’s two blades can with­stand huge vol­umes of wa­ter mov­ing as fast as 4 knots. The top­most part floats just above the sur­face, and the rest of the equip­ment is held in place with moor­ing lines to the ocean floor, mak­ing it quicker to de­ploy and cheaper to main­tain. Re­pair crews take an el­e­va­tor down the shaft. Ri­val tur­bine mak­ers dig deep into the ocean floor to an­chor the ma­chin­ery so that it can with­stand the strength of the cur­rents; their re­pairs re­quire rais­ing the struc­ture to the sur­face. That pushes up the cost sig­nif­i­cantly, Dehlsen says, to about five to seven times more than Aquan­tis’s.

Dehlsen plans to in­stall his tur­bines in a few test sites and sell power to the grid. He sees a sec­ond rev­enue stream in marine tur­bines hous­ing data cen­ters for the world’s tech gi­ants, us­ing the tur­bine’s shaft as a stor­age area for racks of servers. That can save com­pa­nies money on air con­di­tion­ing by us­ing cold ocean wa­ter to cool the equip­ment. Aquan­tis de­signed and built a pi­lot test cham­ber for Mi­crosoft that housed a data cen­ter un­der­wa­ter for 105 days off Cal­i­for­nia’s San Luis Obispo pier last year. The test was a suc­cess, Mi­crosoft said, with min­i­mal ocean heat­ing and no leaks or hard­ware fail­ures. Dehlsen is reaching out to Ap­ple, Face­book, and Google about sim­i­lar ef­forts.

Dehlsen is court­ing tech com­pa­nies and in­vestors while try­ing to lock down test sites from the north coast of Brazil to Cape Agul­has, on the south­ern tip of Africa. Lit­tle test­ing has taken place in the U.S. Aquan­tis has won Depart­ment of En­ergy grants but no ven­ture cap­i­tal. Dehlsen has self-funded a lot of the work; ad­di­tional in­come comes from projects like the data cen­ter pro­gram. His track record in re­new­able en­ergy re­as­sures po­ten­tial part­ners, says Charles Vinick, Aquan­tis’s chief ex­ec­u­tive of­fi­cer. “Jim is seen as the fa­ther of Amer­i­can wind—that opens the door.” Marine tur­bines face some chal­lenges, such as con­cerns over un­known en­vi­ron­men­tal ef­fects. Their blades could strike whales or cre­ate noise that con­fuses sea life. Dehlsen says stud­ies con­ducted in the U.K. show tur­bines are safe for fish and marine life. The big­ger chal­lenge, he says, is cre­at­ing marine en­ergy that is cost­com­pet­i­tive. He ex­pects to get to less than 10¢ a kilo­watt-hour in three to five years. (Wind en­ergy hov­ers from 3¢ to 8¢ a kilo­watt-hour, so­lar from 4¢ to 7¢, and con­ven­tional gas from 5¢ to 8¢.) “In re­new­able en­ergy, peo­ple get en­thu­si­as­tic about an idea, and yes, maybe you can make elec­tric­ity. But if it’s 8¢ a kilo­watt-hour, so what?” he says. “Don’t even bother.”

Dehlsen’s best ar­gu­ment may be a slide in his pre­sen­ta­tion about the urgency of global warm­ing. “The time that’s left in which we can make a change is rel­a­tively short,” he says. “Five to 10 years, and you’re be­yond be­ing able to stem it.”

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