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<br />One of the biggest problems in solar
<br />technology is what to do when the sun is
<br />not shining. Now, encouraged by suc-
<br />cessful research in Israel, scientists at
<br />Southern California Edison Co. and the
<br />Jet Propulsion Laboratory (JPL) are con-
<br />vinced that salt-water "solar ponds,"
<br />which trap the sun's heat by day and
<br />release it gradually at night or during
<br />inclement weather, can be used to gener-
<br />ate a steady supply of electricity at a
<br />cost competitive with oil or natural gas.
<br />Edison already has begun preliminary
<br />engineering work on a 5-Mw pilot proj-
<br />ect t.t the Salton Sea, 140 mi. southeast
<br />of Los Angeles, and JPL engineer Robert
<br />L. French avidly asserts that "a solar
<br />pond can generste electricity at 25 % the
<br />cost of any other solar technology.
<br />"If we are really serious about solar
<br />technology, this certainly is the best
<br />option we have today," says French, who
<br />adds that unlike many alternative ener-
<br />gy sources, the technology for solar
<br />ponds '~s here, ready to be utilized."
<br />On 10 bigge, thing.. Edison is hoping that
<br />success with its solar-pond project will
<br />allow it to go shead with plans for a 600-
<br />Mw commercial-scale plant, equal in ca-
<br />pacity to a large coal-fired generating
<br />station and costing $1.2 billion or more,
<br />and it is joined in its enthusiasm by the
<br />Energy Dept. and its state
<br />counterpart in California.
<br />Edison and the state agency
<br />are each slated to pay 25% nf
<br />the pilot project's estimated
<br />$20 million cost, and the En-
<br />ergy Dept. is picking up the
<br />remaining half.
<br />Gerald W. Braun, director
<br />of Energy's solar-thermal en-
<br />ergy systems division, cau.
<br />tions that there may not be
<br />sufficient funds in either the
<br />fiscal 1981 or 1982 budgets to
<br />complete the pilot project by
<br />1983, as originally planned.
<br />But he, too, ,remains optimis-
<br />tic. "In just about any budget
<br />scenario except complete col-
<br />lapse, the Salton Sea project
<br />has high priority.for us."
<br />"To date," says French,
<br />"the DOE hasn't impacted our
<br />planned implementation of
<br />the Salton Sea project, and I
<br />think we are the only area of
<br />solar not affected" by Reagan
<br />Administration budget-cut-
<br />ting. "This project has to re-
<br />main attractive for DOE be-
<br />eause ntlu... ,.v'1}- aWl nut-
<br />tIii& up 50% of the costa."
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<br />Solar ponds:
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<br />40P BUSINESS WEEK: AprtI20, 1081
<br />Job No. 20217
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<br />Meanwhile, scientists at Utah State
<br />University in Logan say a proposed solar
<br />pond at the Great Salt Lake could be in
<br />operation even before the Californis pi-
<br />lot if the Interior Dept. approves a
<br />request for funding. And two federal riv-
<br />er pollution-control projects, one on the
<br />Red River in Texas and Oklahoma and
<br />the other on the Colorado River in areas
<br />of Utah and Southern California, could
<br />include solar ponds in efforts to lower
<br />the salinity of river water.
<br />Proml.lng _omlco. In both river proj-
<br />ects, brine would be collected in man-
<br />made storage ponds that could easily be
<br />tapped for power production. Says Mich-
<br />ael J. Clinton, chief of the Colorado Riv-
<br />er Water Quality Office of Interior's
<br />Water & Power Resources Service: ''The
<br />economics [of solar ponds] look reasona-
<br />bly good." At the Red River project, ''we
<br />feel there's sufficient evidence that it
<br />would be feasible and economic at this
<br />point to warrant going ahead" with an
<br />electric power venture, says Harvey K.
<br />Bollinger, a civil engineer with the U. S.
<br />Army Corps of Engineers in Tulsa.
<br />A solar pond, usually 6 ft. to 20 ft.
<br />deep and covering 250 acres in the case
<br />of the pilot project, relies on mud or a
<br />dark bottom material to absorb the sun's
<br />heat, which then is trapped in a high-
<br />
<br />saline layer of water near the bottom.
<br />The heat cannot rise and dissipate be-
<br />cause the layer above has only 20% the
<br />salinity of the lower level; differences in
<br />density prevent the layers from mixing
<br />significantly. While the lower water lay-
<br />er will not usually reach the boiling
<br />
<br />Reliable source: A
<br />built-In cepaclty to store
<br />large quantities of heat
<br />
<br />point, at about 180 F it is hot enough to
<br />boil Freon 114 gas, and the resulting
<br />vapor is ~ to powgr a.f'! ~lectriei'tJ,-
<br />generating turbine.
<br />Proponents of solar ponds argue that
<br />one in a sunny area such as Southern
<br />California can provide a base-load ca-
<br />pacity as reliable as an oil-fired power
<br />plant. Most other alternative energy
<br />sources, such as wind, hydro, or other
<br />solar projects, provide utilities only with
<br />peaking power when the wind is blowing,
<br />or the rain is raising river levels, or the
<br />sun is shining.
<br />Solar ponds, on the other hand, have a
<br />built-in capacity to store large quantities
<br />of heat. The trick is to match the size of
<br />an electrical generating unit to the stor-
<br />age capacity of the pond so that it does
<br />not extract more thermal energy than
<br />the sun can provide. JPL'S French be-
<br />lieves an efficient solar pond could sup-
<br />ply enough heat to generate power for a
<br />period of two weeks to a month, even
<br />with no sunny days at all.
<br />.....1.. pond. Because of their capacity to
<br />store, French asserts, ponds 'could be
<br />supplying 3% or 4% of the nation's total
<br />energy needs by the end of the century,
<br />twice the amount predicted for wind
<br />power. And, estimates Carl E. Nielsen,
<br />an Ohio State University physics profes-
<br />sor, the cost of solar-pond power could
<br />be as low as 84 to 1~ per kwh, as com-
<br />pared with 7, to l~ per kwh for elec.
<br />tricity generated by the new coal, oil,
<br />and nuclear plants of today.
<br />~ . ";". ,. Y;. "Ii Nielsen's proj~ coat of electricity
<br />~.. . .;:.+'l'" ''':: from solar ponds IS close to the goal of
<br />;. ..' .. \.":~."~'. 7.~ per kwh Israel has set in its drive to
<br />lll.. l. : ... install 2,000 Mw of solar capacity by the
<br />1;"~, .1'1,1 i f-" " . ~ "'~J end of the century. Ormat Turbines Ltd.
<br />. 1. "'~~ .1.. '" }~~~'-'.,.t I than has bee .
<br />. . "~ ~:,. ,~.. ....,.. -=-- ......,:'<.'.,.. .or more a year n operatmg
<br />: . ,\..' . , -:"_. '. ,. ~~"'-~ Ie,. the world's first commercial solar pond
<br />. -Z:L-~.. '.:'.~~. :i~~,z.:!J .. in Ein Bokck on the Dead Sea as part of
<br /><\~;,...,~Cl!! ~."........ ,.' j I a 150-kw project, and it plans to con-
<br />..~,.,. . .. ""'~. .~ .>~".~' ..t,c"! W struct a 82.5-acre pond to power a 5-Mw
<br />~:. . .'. t ~.;-:'";,; ,~.~,:;! \:~. .; t insta11atio!, on th~ sea later in 1981. The
<br />. ...... "'"....,.....~", ": ". . I 5-Mw proJect ''will make or break the
<br />... . commercial viability of solar ponds,"
<br />Engl....' French: A solar pond can generate power says Ormat Managing Director Yehuda
<br />~ the coet 01 any other solar technology." Bronicki. -
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