History of Solar Energy

History of Solar Energy
Revisiting Solar Power's Past
by Charles Smith
Home Location: - Technology Review: July 95: Solar Power
Inventors unlocke the secrets o! turning the sun"s rays into mechanical #ower more
than a century ago$ only to see their ream machines colla#se !rom lack o! #u%lic
su##ort& 'oern solar engineers must not %e oome to relive their !ate&
Charles Smith is an adjunct faculty member in the Department of Technology at
Appalachian State University, and a doctoral candidate in the Department of Science
and Technology Studies at Virginia Polytechnic nstitute! "is primary area of
research is the history of energy!
'any o! us assume that the !irst serious #ush to evelo# renewa%le !uels was
s#awne while angry (mericans waite in gas lines uring the )energy crisis) o! the
*9+,s& Hel hostage %y the -P./ oil em%argo$ the country suenly seeme
rece#tive to warnings !rom scientists$ environmentalists$ an even a !ew #oliticians
to en its over-reliance on !inite coal an oil reserves or !ace severe economic
istress an #olitical u#heaval&
0ut e!!orts to esign an construct evices !or su##lying renewa%le energy actually
%egan some *,, years %e!ore that tur%ulent time--ironically$ at the very height o!
the Inustrial Revolution$ which was largely !oune on the #romise o! seemingly
ine1hausti%le su##lies o! !ossil !uels& /ontrary to the #revailing o#inion o! the ay$ a
num%er o! engineers 2uestione the #ractice o! an inustrial economy %ase on
nonrenewa%le energy an worrie a%out what the worl"s nations woul o a!ter
e1hausting the !uel su##ly&
'ore im#ortant$ many o! these visionaries i not 3ust #rovie !uturistic rhetoric %ut
actively e1#lore almost all the renewa%le energy o#tions !amiliar toay& In the en$
most ecie to !ocus on solar #ower$ reasoning that the #otential rewars
outweighe the technical %arriers& In less than 5, years$ these #ioneers evelo#e
an im#ressive array o! innovative techni2ues !or ca#turing solar raiation an using
it to #rouce the steam that #owere the machines o! that era& In !act$ 3ust %e!ore
4orl 4ar I$ they ha outline all o! the solar thermal conversion methos now
%eing consiere& 5n!ortunately$ es#ite their technical successes an innovative
esigns$ their work was largely !orgotten !or the ne1t 5, years in the rush to evelo#
!ossil !uels !or an energy-hungry worl&
6ow$ a century later$ history is re#eating itsel!& (!ter !ollowing the same #ath as the
early inventors--in some cases reinventing the same techni2ues--contem#orary solar
engineers have arrive at the same conclusion: solar #ower is not only #ossi%le %ut
eminently #ractical$ not to mention more environmentally !rienly& (las$ once again$
3ust as the technology has #roven itsel! !rom a #ractical stan#oint$ #u%lic su##ort
!or !urther evelo#ment an im#lementation is eroing$ an solar #ower coul yet
again %e ecli#se %y conventional energy technologies&
The First Solar Motor
The earliest known recor o! the irect conversion o! solar raiation into mechanical
#ower %elongs to (uguste 'ouchout$ a mathematics instructor at the Lyce e Tours&
'ouchout %egan his solar work in *78, a!ter e1#ressing grave concerns a%out his
country"s e#enence on coal& )It woul %e #ruent an wise not to !all aslee#
regaring this 2uasi-security$) he wrote& ).ventually inustry will no longer !in in
.uro#e the resources to satis!y its #roigious e1#ansion& /oal will unou%tely %e
use u#& 4hat will inustry o then9) 0y the !ollowing year he was grante the !irst
#atent !or a motor running on solar #ower an continue to im#rove his esign until
a%out *77,& :uring this #erio the inventor lai the !ounation !or our moern
unerstaning o! converting solar raiation into mechanical steam #ower&
'ouchout"s initial e1#eriments involve a glass-enclose iron caulron: incoming
solar raiation #asse through the glass cover$ an the tra##e rays transmitte
heat to the water& 4hile this sim#le arrangement %oile water$ it was o! little
#ractical value %ecause the 2uantities an #ressures o! steam it #rouce were
minimal& However$ 'ouchout soon iscovere that %y aing a re!lector to
concentrate aitional raiation onto the caulron$ he coul generate more steam& In
late *785$ he succeee in using his a##aratus to o#erate a small$ conventional
steam engine&
0y the !ollowing summer$ 'ouchout is#laye his solar motor to .m#eror 6a#oleon
III in Paris& The monarch$ !avora%ly im#resse$ o!!ere !inancial assistance !or
evelo#ing an inustrial solar motor !or ;rance& 4ith the newly ac2uire !uns$
'ouchout enlarge his invention"s ca#acity$ re!ine the re!lector$ reesigning it as a
truncate cone$ like a ish with slante sies$ to more accurately !ocus the sun"s
rays on the %oiler& 'ouchout also constructe a tracking mechanism that ena%le the
entire machine to !ollow the sun"s altitue an a<imuth$ #roviing uninterru#te solar
rece#tion& (!ter si1 years o! work$ 'ouchout e1hi%ite his new machine in the li%rary
courtyar o! his Tours home in *7+=$ ama<ing s#ectators& -ne re#orter escri%e the
re!lector as an inverte )mammoth lam# shae&&&coate on the insie with very thin
silver lea!) an the %oiler sitting in the mile as an )enormous thim%le) mae o!
%lackene co##er an )covere with a glass %ell&)
(n1ious to #ut his invention to work$ he connecte the a##aratus to a steam engine
that #owere a water #um#& -n what was eeme )an e1ce#tionally hot ay$) the
solar motor #rouce one-hal! horse#ower& 'ouchout re#orte the results an
!inings to the ;rench (caemy o! Science& The government$ eager to e1#loit the
new invention to its !ullest #otential$ ecie that the most suita%le venue !or the
new machine woul %e the tro#ical climes o! the ;rench #rotectorate o! (lgeria$ a
region %lesse with almost constant sunshine an entirely e#enent on coal$ a
#rohi%itively e1#ensive commoity in the (!rican region&
'ouchout was 2uickly e#loye to (lgeria with am#le !uning to construct a large
solar steam engine& He !irst ecie to enlarge his invention"s ca#acity yet again to
*,, liters >+, !or water an ?, !or steam@ an em#loy a multi-tu%e %oiler instea o!
the single caulron& The %oiler tu%es ha a %etter sur!ace-area-to-water ratio$
yieling more #ressure an im#rove engine #er!ormance&
In *7+7$ 'ouchout e1hi%ite the reesigne invention at the Paris .1#osition&
Perha#s to im#ress the auience or$ more likely$ his government %ackers$ he cou#le
the steam engine to a re!rigeration evice& The steam !rom the solar motor$ a!ter
%eing route through a conenser$ ra#ily coole the insie o! a se#arate insulate
com#artment& He e1#laine the result: )In s#ite o! the seeming #arao1 o! the
statement$ Ait wasB #ossi%le to utili<e the rays o! the sun to make ice&) 'ouchout was
aware a meal !or his accom#lishments&
0y *77* the ;rench 'inistry o! Pu%lic 4orks$ intrigue %y 'ouchout"s machine$
a##ointe two commissioners to assess its cost e!!iciency& 0ut a!ter some 9,,
o%servations at 'ont#elier$ a city in southern ;rance$ an /onstantine$ (lgeria$ the
government eeme the evice a technical success %ut a #ractical !ailure& -ne
reason was that ;rance ha recently im#rove its system !or trans#orting coal an
evelo#e a %etter relationshi# with .nglan$ on which it was e#enent !or that
commoity& The #rice o! coal ha thus ro##e$ renering the nee !or alternatives
less attractive& 5na%le to #rocure !urther !inancial assistance$ 'ouchout returne to
his acaemic #ursuits&
The Tower of Power
:uring the height o! 'ouchout"s e1#erimentation$ 4illiam (ams$ the e#uty
registrar !or the .nglish /rown in 0om%ay$ Inia$ wrote an awar-winning %ook
entitle Solar Heat: ( Su%stitute !or ;uel in Tro#ical /ountries& (ams note that he
was intrigue with 'ouchout"s solar steam engine a!ter reaing an account o! the
Tours emonstration$ %ut that the invention was im#ractical$ since )it woul %e
im#ossi%le to construct Aa ish-sha#e re!lectorB o! much greater imensions) to
generate more than 'ouchout"s one-hal! horse#ower& The #ro%lem$ he !elt$ was that
the #olishe metal re!lector woul tarnish too easily$ an woul %e too costly to %uil
an too unwiely to e!!iciently track the sun&
;ortunately !or the in!ant solar isci#line$ the .nglish registrar i not s#en all his
time !ining !aults in the ;rench inventor"s e!!orts$ %ut o!!ere some creative
solutions& ;or e1am#le$ (ams was convince that a re!lector o! !lat silvere mirrors
arrange in a semicircle woul %e chea#er to construct an easier to maintain& His
#lan was to %uil a large rack o! many small mirrors an a3ust each one to re!lect
sunlight in a s#eci!ic irection& To track the sun"s movement$ the entire rack coul %e
rolle aroun a semicircular track$ #ro3ecting the concentrate raiation onto a
stationary %oiler& The rack coul %e attene %y a la%orer an woul have to %e
move only )three or !our times uring the ay$) (ams note$ or more !re2uently to
im#rove #er!ormance&
/on!ient o! his innovative arrangement$ (ams %egan construction in late *7+7& 0y
graually aing *+-%y-*,-inch !lat mirrors an measuring the rising tem#eratures$
he calculate that to generate the *$=,,C ; necessary to #rouce steam #ressures
high enough to o#erate conventional engines$ the re!lector woul re2uire += mirrors&
To emonstrate the #ower o! the concentrate raiation$ (ams #lace a #iece o!
woo in the !ocus o! the mirrore #anes where$ he note$ )it ignite immeiately&)
He then arrange the collectors aroun a %oiler$ retaining 'ouchout"s enclose
caulron con!iguration$ an connecte it
to a =&5-horse#ower steam engine that
o#erate uring aylight hours )!or a
!ortnight in the com#oun o! AhisB
%ungalow&)
.ager to is#lay his invention$ (ams
noti!ie news#a#ers an invite his
im#ortant !riens--incluing the (rmy"s
commaner in chie!$ a colonel !rom the
Royal .ngineers$ the secretary o! #u%lic
works$ various 3ustices$ an #rinci#al mill
owners--to a emonstration& (ams wrote that all were im#resse$ even the local
engineers who$ while ou%t!ul that solar #ower coul com#ete irectly with coal an
woo$ thought it coul %e a #ractical su##lemental energy source&
(ams"s e1#erimentation ene soon a!ter the emonstration$ though$ #erha#s
%ecause he ha achieve his goal o! #roving the !easi%ility o! his %asic esign$ %ut
more likely %ecause$ as some say$ he lacke su!!icient entre#reneurial rive& .ven
so$ his legacy o! #roucing a #ower!ul an versatile way to harness an convert solar
heat survives& .ngineers toay know this esign as the Power Tower conce#t$ which
is one o! the %est con!igurations !or large scale$ centrali<e solar #lants& In !act$
most o! the moern tower-ty#e solar #lants !ollow (ams"s %asic con!iguration: !lat
or slightly curve mirrors that remain stationary or travel on a semicircular track an
either re!lect light u#war to a %oiler in a receiver tower or ownwar to a %oiler at
groun level$ there%y generating steam to rive an accom#anying heat engine&
Collection without Reflection
.ven with 'ouchout"s a%anonment an the a##arent isenchantment o! .nglan"s
sole #artici#ant$ .uro#e continue to avance the #ractical a##lication o! solar heat$
as the torch returne to ;rance an engineer /harles Tellier& /onsiere %y many the
!ather o! re!rigeration$ Tellier actually %egan his work in re!rigeration as a result o!
his solar e1#erimentation$ which le to the esign o! the !irst no concentrating$ or
non-re!lecting$ solar motor&
In *775$ Tellier installe a solar collector on his roo! similar to the !lat-#late
collectors #lace ato# many homes toay !or heating omestic water& The collector
was com#ose o! ten #lates$ each consisting o! two iron sheets rivete together to
!orm a watertight seal$ an connecte %y tu%es to !orm a single unit& Instea o!
!illing the #lates with water to #rouce steam$ Tellier chose ammonia as a working
!lui %ecause o! its signi!icantly lower %oiling #oint& (!ter solar e1#osure$ the
containers emitte enough #ressuri<e ammonia gas to #ower a water #um# he ha
#lace in his well at the rate o! some ?,, gallons #er hour uring aylight& Tellier
consiere his solar water #um# #ractical !or anyone with a south-!acing roo!& He
also thought that sim#ly aing #lates$ there%y increasing the si<e o! the system$
woul make inustrial a##lications #ossi%le&
0y *779 Tellier ha increase the e!!iciency o! the collectors %y enclosing the to#
with glass an insulating the %ottom& He #u%lishe the results in The .levation o!
4ater with the Solar (tmos#here$ which inclue etails on his intentions to use the
sun to manu!acture ice& Like his countryman 'ouchout$ Tellier envisione that the
large e1#anses o! the (!rican #lains coul %ecome inustrially an agriculturally
#rouctive through the im#lementation o! solar #ower&
In The Peace!ul /on2uest o! 4est (!rica$ Tellier argue that a consistent an reaily
availa%le su##ly o! energy woul %e re2uire to #ower the machinery o! inustry
%e!ore the ;rench holings in (!rica coul %e #ro#erly evelo#e& He also #ointe out
that even though the #rice o! coal ha !allen since 'ouchout"s e1#eriments$ !uel
continue to %e a signi!icant e1#ense in ;rench o#erations in (!rica& He there!ore
conclue that the construction costs o! his low-tem#erature$ non-concentrating
solar motor were low enough to 3usti!y its im#lementation& He also note that his
machine was !ar less costly than 'ouchout"s evice$ with its ish-sha#e re!lector
an com#licate tracking mechanism&
Det es#ite this #otential$ Tellier eviently ecie to #ursue his re!rigeration
interests instea$ an o so without the ai o! solar heat& 'ost likely the #ro!its !rom
conventionally o#erate re!rigerators #rove irresisti%le& (lso$ much o! the eman
!or the new cooling technology now stemme !rom the esire to trans#ort %ee! to
.uro#e !rom 6orth an South (merica& The rolling motion o! the shi#s com%ine with
s#ace limitations #reclue the use o! solar #ower altogether& (n as Tellier
reirecte his !ocus$ ;rance saw the last ma3or evelo#ment o! solar mechanical
#ower on her soil until well into the twentieth century& 'ost e1#erimentation in the
!legling isci#line crosse the (tlantic to that new %astion o! mechanical ingenuity$
the 5nite States&
The Parabolic Trough
Though Sweish %y %irth$ John .ricsson was one o! the most in!luential an
controversial 5&S& engineers o! the nineteenth century& 4hile he s#ent his most
#rouctive years esigning machines o! war--his most cele%rate accom#lishment
was the /ivil 4ar %attleshi# the 'onitor--he eicate the last =, years o! his li!e
largely to more #eace!ul #ursuits such as solar #ower& This work was ins#ire %y a
!ear share %y virtually all o! his !ellow solar inventors that coal su##lies woul
someay en& In *787 he wrote$ )( cou#le o! thousan years ro##e in the ocean
o! time will com#letely e1haust the coal !iels o! .uro#e$ unless$ in the meantime$
the heat o! the sun %e em#loye&)
Thus %y *7+, .ricsson ha evelo#e what he claime to %e the !irst solar-#owere
steam engine$ ismissing 'ouchout"s machine as )a mere toy&) In truth$ .ricsson"s
!irst esigns greatly resem%le 'ouchout"s evices$ em#loying a conical$ ish-sha#e
re!lector that concentrate solar raiation onto a %oiler an a tracking mechanism
that ke#t the re!lector irecte towar the sun&
Though un3usti!ie in claiming his esign original$ .ricsson soon i invent a novel
metho !or collecting solar rays--the #ara%olic trough& 5nlike a true #ara%ola$ which
!ocuses solar raiation onto a single$ relatively small area$ or !ocal #oint$ like a
satellite television ish$ a #ara%olic trough is more akin to an oil rum cut in hal!
lengthwise that !ocuses solar rays in a line across the o#en sie o! the re!lector& This
ty#e o! re!lector o!!ere many avantages over its circular >ish-sha#e@
counter#arts: it was com#aratively sim#le$ less e1#ensive to construct$ an$ unlike a
circular re!lector$ ha only to track the sun in a single irection >u# an own$ i! lying
hori<ontal$ or east to west i! staning on en@$ thus eliminating the nee !or com#le1
tracking machinery& The ownsie was that the evice"s tem#eratures an
e!!iciencies were not as high as with a ish-sha#e re!lector$ since the con!iguration
s#rea raiation over a wier area--a line rather than a #oint& Still$ when .ricsson
constructe a single linear %oiler >essentially a #i#e@$ #lace it in the !ocus o! the
trough$ #ositione the new arrangement towar the sun$ an connecte it to a
conventional steam engine$ he claime the machine ran success!ully$ though he
ecline to #rovie #ower ratings&
The new collection system %ecame #o#ular with later e1#erimenters an eventually
%ecame a stanar !or moern #lants& In !act$ the largest solar systems in the last
ecae have o#te !or .ricsson"s #ara%olic trough re!lector %ecause it strikes a goo
engineering com#romise %etween e!!iciency an ease o! o#eration&
;or the ne1t ecae$ .ricsson continue to re!ine his invention$ trying lighter
materials !or the re!lector an sim#li!ying its construction& 0y *777$ he was so
con!ient o! his esign"s #ractical #er!ormance that he #lanne to mass-#rouce an
su##ly the a##aratus to the )owners o! the sun%urnt lans on the Paci!ic coast) !or
agricultural irrigation&
5n!ortunately !or the struggling isci#line$ .ricsson ie the !ollowing year& (n
%ecause he was a sus#icious an$ some sai$ #aranoi man who ke#t his esigns to
himsel! until he !ile #atent a##lications$ the etaile #lans !or his im#rove sun
motor ie with him& 6evertheless$ the search !or a #ractical solar motor was not
a%anone& In !act$ the e1#erimentation an evelo#ment o! large-scale solar
technology was 3ust %eginning&
The First Commercial Venture
0oston resient (u%rey .neas %egan his solar motor e1#erimentation in *79=$
!orme the !irst solar #ower com#any >The Solar 'otor /o&@ in *9,,$ an continue
his work until *9,5& -ne o! his !irst e!!orts resulte in a re!lector much like .ricsson"s
early #ara%olic trough& 0ut .neas !oun that it coul not attain su!!iciently high
tem#eratures$ an$ una%le to unlock his #reecessor"s secrets$ ecie to scra# the
conce#t altogether an return to 'ouchout"s truncate-cone re!lector& 5n!ortunately$
while 'ouchout"s a##roach resulte in higher tem#eratures$ .neas was still
issatis!ie with the machine"s #er!ormance& His solution was to make the %ottom o!
the re!lector"s truncate cone-sha#e ish larger %y esigning its sies to %e more
u#right to !ocus raiation onto a %oiler that was 5, #ercent larger&
;inally satis!ie with the results$ he ecie to avertise his esign %y e1hi%iting it in
sunny Pasaena$ /ali!&$ at .win /awston"s ostrich !arm$ a #o#ular tourist attraction&
The monstrous machine i not !ail to attract attention& Its re!lector$ which s#anne
?? !eet in iameter$ containe *$+77 iniviual mirrors& (n its %oiler$ which was
a%out *? !eet in length an a !oot wie$ hel *,, gallons o! water& (!ter e1#osure to
the sun$ .neas"s evice %oile the water an trans!erre steam through a !le1i%le
#i#e to an engine that #um#e *$E,, gallons o! water #er minute !rom a well onto
the ari /ali!ornia lansca#e&
6ot everyone gras#e the conce#t& In !act$ one man thought the solar machine ha
something to o with the incu%ation o! ostrich eggs& 0ut .neas"s marketing savvy
eventually #ai o!!& :es#ite the occasional misconce#tions$ thousans who visite
the !arm le!t convince that the sun machine woul soon %e a !i1ture in the sunny
Southwest& 'oreover$ many regional news#a#ers an #o#ular-science 3ournals sent
re#orters to the !arm to cover the s#ectacle& To ;rank 'illar$ a re#orter !or the
%ran new maga<ine 4orl"s 4ork$ the #otential o! solar motors #lace in 2uantity
across the lan ins#ire !uturistic visions o! a region )where oranges may %e
growing$ lemons yellowing$ an gra#es #ur#ling$ uner the glare o! the sun which$
while it ri#ens the !ruits it will also water an nourish them&) He also #reicte that
the #otential !or this novel machine was not limite to irrigation: )I! the sun motor
will #um# water$ it will also grin grain an saw lum%er an run electric cars&)
The !uture$ like the machine itsel!$ looke %right an shiny& In *9,? .neas$ reay to
market his solar motor$ move his 0oston-%ase com#any to Los (ngeles$ closer to
#otential customers& 0y early the !ollowing year he ha sol his !irst com#lete
system !or F=$*8, to :r& (& J& /hanler o! 'esa$ (ri<& 5n!ortunately$ a!ter less than
a week$ the rigging su##orting the heavy %oiler weakene uring a winstorm an
colla#se$ sening it tum%ling into the re!lector an amaging the machine %eyon
re#air&
0ut .neas$ accustome to set%acks$ ecie to #ush onwar an constructe
another solar #um# near Tem#e$ (ri<& Seven long months later$ in the !all o! *9,E$
John 'ay$ a rancher in 4ilco1$ (ri<&$ %ought another machine !or F=$5,,&
5n!ortunately$ shortly a!terwar$ it was estroye %y a hailstorm& This secon
weather-relate incient all %ut #rove that the massive #ara%olic re!lector was too
susce#ti%le to the tur%ulent climactic conitions o! the esert southwest& (n una%le
to survive on such measly sales$ the com#any soon !ole&
Though the machine i not %ecome a !i1ture as .neas ha ho#e$ the inventor
contri%ute a great eal o! scienti!ic an technical ata a%out solar heat conversion
an initiate more than his share o! #u%lic e1#osure& :es#ite his %usiness !ailure$ the
lure o! limitless !uel was strong$ an while .neas an the Solar 'otor /om#any were
sus#ening their o#erations$ another solar #ioneer was 3ust %eginning his&
Moonlight !eration
Henry .& 4illsie %egan his solar motor construction a year %e!ore .neas"s com#any
!ole& In his o#inion$ the lessons o! 'ouchout$ (ams$ .ricsson$ an .neas #rove
the cost ine!!iciency o! high-tem#erature$ concentrating machines& He was convince
that a non re!lective$ lower-tem#erature collection system similar to Tellier"s
invention was the %est metho !or irectly utili<ing solar heat& The inventor also !elt
that a solar motor woul never %e #ractical unless it coul o#erate aroun the clock&
Thus thermal storage$ a #ractice that lent itsel! to low-tem#erature o#eration$ was
the !ocus o! his e1#erimentation&
To store the sun"s energy$ 4illsie %uilt large !lat-#late collectors that heate
hunres o! gallons o! water$ which he ke#t warm all night in a huge insulate %asin&
He then su%merge a series o! tu%es$ or va#ori<ing #i#es$ insie the %asin to serve
as %oilers& 4hen the acting meium--4illsie #re!erre sul!ur io1ie to Tellier"s
ammonia--#asse through the #i#es$ it trans!orme into a high-#ressure va#or$
which #asse to the engine$ o#erate it$ an e1hauste into a conensing tu%e$
where it coole$ returne to a li2ui state$ an was reuse&
In *9,E$ con!ient that his esign woul #rouce continuous #ower$ he %uilt two
#lants$ a 8-horse#ower !acility in St& Louis$ 'o&$ an a *5-horse#ower o#eration in
6eeles$ /ali!& (n a!ter several #ower trials$ 4illsie ecie to test the storage
ca#acity o! the larger system& (!ter arkness ha !allen$ he o#ene a valve that
)allowe the solar-heate water to !low over the e1changer #i#es an thus start u#
the engine&) 4illsie ha create the !irst solar evice that coul o#erate at night
using the heat gathere uring the ay& He also announce that the *5-horse#ower
machine was the most #ower!ul arrangement constructe u# to that time& 0esie
o!!ering a way to #rovie continuous solar #ower #rouction$ 4illsie also !urnishe
etaile cost com#arisons to 3usti!y his e!!orts: the solar #lant e1acte a two-year
#ay%ack #erio$ he claime$ an e1ce#tional value even when com#are with toay"s
stanars !or alternative energy technology&
-riginally$ like .ricsson an .neas %e!ore him$ 4illsie #lanne to market his evice
!or esert irrigation& 0ut in his later #atents 4illsie wrote that the invention was
)esigne !or !urnishing #ower !or electric light an #ower$ re!rigerating an ice
making$ !or milling an #um#ing at mines$ an !or other #ur#oses where large
amounts o! #ower are re2uire&)
4illsie etermine all that was le!t to o was to o!!er his !uturist invention !or sale&
5n!ortunately$ no %uyers emerge& :es#ite the !avora%le long-term cost analysis$
#otential customers were sus#icious o! the machine"s ura%ility$ eterre %y the high
ratio o! machine si<e to #ower out#ut$ an !ear!ul o! the initial investment cost o!
4illsie"s ingenious solar #ower #lant& His com#any$ like others %e!ore it$
isintegrate&
" Certain Technical Maturity
:es#ite solar #ower"s ismal commercial !ailures$ some #ro#onents continue to
%elieve that i! they coul only !in the right com%ination o! solar technologies$ the
vision o! a !ree an unlimite #ower source woul come true& ;rank Shuman was one
who share that ream& 0ut unlike most reamers$ Shuman i not have his hea in
the clous& In !act$ his harheae a##roach to %usiness an his #ersistent search
!or #ractical solar #ower le him an his colleagues to construct the largest an most
cost-e!!ective machine #rior to the s#ace age&
Shuman"s !irst e!!ort in *9,8 was similar to 4illsie"s !lat-#late collector esign e1ce#t
that it em#loye ether as a working !lui instea o! sul!ur io1ie& The machine
#er!orme #oorly$ however$ %ecause even at res#ecta%le #ressures$ the steam--or
more accurately$ the va#or--e1erte com#aratively little !orce to rive a motor
%ecause o! its low s#eci!ic gravity&
Shuman knew he neee more heat to #rouce steam$ %ut !elt that using
com#licate re!lectors an tracking evices woul %e too costly an #rone to
mechanical !ailure& He ecie that rather than trying to generate more heat$ the
answer was to %etter conserve the heat alreay %eing a%sor%e&
In *9*,$ to im#rove the collector"s insulation #ro#erties$ Shuman enclose the
a%sor#tion #lates not with a single sheet o! glass %ut with ual #anes se#arate %y a
one-inch air s#ace& He also re#lace the %oiler #i#es with a thin$ !lat metal container
similar to Tellier"s original greenhouse esign& The a##aratus coul now consistently
%oil water rather than ether& 5n!ortunately$ however$ the #ressure was still
insu!!icient to rive inustrial-si<e steam engines$ which were esigne to o#erate
uner #ressures #rouce %y hotter-%urning coal or woo&
(!ter etermining that the cost o! %uiling a larger a%sor%er woul %e #rohi%itive$
Shuman reluctantly concee that the aitional heat woul have to %e #rovie
through some !orm o! concentration& He thus evise a low-cost re!lector stringing
together two rows o! orinary mirrors to ou%le the amount o! raiation interce#te&
(n in *9**$ a!ter !orming the Sun Power /o&$ he constructe the largest solar
conversion system ever %uilt& In !act$ the new #lant$ locate near his home in
Talcony$ Penn&$ interce#te more than *,$,,, s2uare !eet o! solar raiation& The new
arrangement increase the amount o! steam #rouce$ %ut still i not #rovie the
#ressure he e1#ecte&
6ot easily e!eate$ Shuman !igure that i! he couln"t
raise the #ressure o! the steam to run a conventional
steam engine$ he woul have to reesign the engine to
o#erate at lower #ressures& So he teame u# with .&P&
Haines$ an engineer who suggeste that more #recise
milling$ closer tolerances in the moving com#onents$ an
lighter-weight materials woul o the trick& Haines was
right& 4hen the reworke engine was connecte to the
solar collectors$ it evelo#e ?? horse#ower an rove a
water #um# that gushe ?$,,, gallons #er minute onto
the Talcony soil&
Shuman calculate that the Talcony #lant cost F=,, #er
horse#ower com#are with the F7, o! a conventionally
o#erate coal system--a res#ecta%le !igure$ he #ointe out$ an consiering that the
aitional investment woul %e recou#e in a !ew years %ecause the !uel was !ree&
'oreover$ the !act that this !igure was not initially com#etitive with coal or oil-!ire
engines in the inustrial 6ortheast i not concern him %ecause$ like the ;rench
entre#reneurs %e!ore him$ he was #lanning to shi# the machine to the vast sun%urnt
regions in 6orth (!rica&
To %uy #ro#erty an move the machine there$ new investors were solicite !rom
.nglan an the Sun Power /o& Lt& was create& 0ut with the aitional !inancial
su##ort came sti#ulations& Shuman was re2uire to let 0ritish #hysicist /& G& 0oys
review the workings o! the machine an suggest #ossi%le im#rovements& In !act$ the
#hysicist recommene a raical change& Instea o! !lat mirrors re!lecting the sun
onto a !lat-#late con!iguration$ 0oys thought that a #ara%olic trough !ocusing on a
glass-encase tu%e woul #er!orm much %etter& Shuman"s technical consultant
(&S&.& (ckermann agree$ %ut ae that to %e e!!ective$ the trough woul nee to
track the sun continuously& Shuman !elt that his conce#tion o! a sim#le system was
ra#ily isintegrating&
;ortunately$ when the machine was com#lete 3ust outsie o! /airo$ .gy#t$ in *9*=$
Shuman"s !ears that the increase com#le1ity woul rener the evice im#ractical
#rove un!oune& The /airo #lant out#er!orme the Talcony moel %y a large
margin--the machine #rouce ?? #ercent more steam an generate more than 55
horse#ower--which more than o!!set the higher costs& Sun Power /o&"s solar #um#ing
station o!!ere an e1cellent value o! F*5, #er horse#ower$ signi!icantly reucing the
#ay%ack #erio !or solar-riven irrigation in the region& It looke as i! solar
mechanical #ower ha !inally evelo#e the technical so#histication it neee to
com#ete with coal an oil&
5n!ortunately$ the %eginning was also the en& Two months a!ter the !inal /airo
trials$ (rchuke ;erinan was assassinate in the 0alkans$ igniting the Hreat 4ar&
The !ighting 2uickly s#rea to .uro#e"s colonial holings$ an the u##er regions o!
(!rica were soon engul!e& Shuman"s solar irrigation #lant was estroye$ the
engineers associate with the #ro3ect returne to their res#ective countries to
#er!orm war-relate tasks$ an ;rank Shuman ie %e!ore the armistice was signe&
4hether or not Shuman"s evice woul have initiate the commercial success that
solar #ower es#erately neee$ we will never know& However$ the Sun Power /o&
can %oast a certain technical maturity %y e!!ectively synthesi<ing the ieas o! its
#reecessors !rom the #revious 5, years& The com#any use an a%sor%er >though in
linear !orm@ o! Tellier an 4illsie$ a re!lector similar to .ricsson"s$ sim#le tracking
mechanisms !irst use %y 'ouchout an later em#loye %y .neas$ an com%ine
them to o#erate an engine s#ecially esigne to run with solar-generate steam& In
e!!ect$ Shuman an his colleagues set the stanar !or many o! the most #o#ular
moern solar systems 5, to 8, years %e!ore the !act&
The Most Rational Source
The a!orementione solar #ioneers were only the most nota%le inventors involve in
the evelo#ment o! solar thermal #ower !rom *78, to *9*E& 'any others contri%ute
to the more than 5, #atents an the scores o! %ooks an articles on the su%3ect&
4ith all this so#histication$ why couln"t solar mechanical technology %lossom into a
via%le inustry9 4hy i the isci#line take a 5,-year ive %e!ore again gaining a
measure o! #o#ular interest an technical attention9
;irst$ es#ite the ra#i avances in solar mechanical technology$ the inustry"s
!uture was renere #ro%lematic %y a revolution in the use an trans#ort o! !ossil
!uels& -il an coal com#anies ha esta%lishe a massive in!rastructure$ sta%le
markets$ an am#le su##lies& (lso$ %esies trying to #er!ect the technology$ solar
#ioneers ha the i!!icult task o! convincing ske#tics to see solar energy as
something more than a curiosity& Gisionary rhetoric without reaily tangi%le results
was not well receive %y a #o#ulation accustome to immeiate grati!ication&
Im#roving an aa#ting e1isting #ower technology$ eeme less risky an more
controlle$ seeme to make !ar more sense&
;inally$ the a%ility to im#lement raically new harware re2uires either massive
commitment or the !ailure o! e1isting technology to get the 3o% one& Solar
mechanical #ower #rouction in the late nineteenth an early twentieth centuries i
not meet either criterion& :es#ite warnings !rom note scientists an engineers$
alternatives to what seeme like an ine1hausti%le !uel su##ly i not !it into the 5&S&
agena& 5n!ortunately$ in many ways$ these anti2uate sentiments remain with us
toay& :uring the *9+,s$ while the -P./ nations e1ercise their economic #ower an
as the environmental an )no-nuke) movements gaine momentum$ (mericans
#lotte an inustrial cou# whose slogans were energy e!!iciency an renewa%le
resources& /onse2uently$ mechanical solar #ower--along with its s#ace-age$
electricity-#roucing si%ling #hotovoltaics$ as well as other renewa%le sources such
as win #ower--unerwent a revival& (n uring the ne1t two ecaes$ solar
engineers trie myria techni2ues to satis!y society"s nee !or #ower&
They iscovere that ish-sha#e re!lectors akin to 'ouchout"s an .neas"s esigns
were the most e!!icient %ut also the most e1#ensive an i!!icult to maintain& Low-
tem#erature$ non concentrating systems like 4illsie"s an Tellier"s$ though sim#le
an less sensitive to climatic conitions$ were among the least #ower!ul an
there!ore suite only to small$ s#eci!ic tasks& Stationary re!lectors like those use in
(ams"s evice$ now calle Power Tower systems$ o!!ere a %etter solution %ut were
still #ricey an amage #rone&
0y the mi-*97,s$ contem#orary solar engineers$ like their inustrial-revolution
counter#arts .ricsson an Shuman$ etermine that !or sunny areas$ tracking
#ara%olic troughs were the %est com#romise %ecause they e1hi%ite su#erior cost-to-
#ower ratios in most locations& Such e!!orts le engineers at the Los (ngeles-%ase
Lu< /o& to construct an 7,-megawatt electric #ower #lant using #ara%olic trough
collectors to rive steam-#owere tur%ines& The com#any ha alreay use similar
esigns to %uil nine other solar electric generation !acilities$ #roviing a total o! =+5
megawatts o! #ower& In the #rocess$ Lu< engineers steaily lowere the initial costs
%y o#timi<ing construction techni2ues an taking avantage o! economies o! %uying
material in %ulk to %uil ever-larger #lants until the #rice ro##e !rom =E to *=
cents #er kilowatt hour& The ne1t$ even larger #lant--a ?,,-megawatt !acility--
scheule !or com#letion last year$ #romise to #rovie 8 to + cents #er kilowatt
hour$ near the #rice o! electricity #rouce %y coal$ oil$ or nuclear technology&
-nce again$ as with Shuman an his team$ the ga# was closing& 0ut once again
these !acilities woul not %e %uilt& Lu<$ #roucer o! more than 95 #ercent o! the
worl"s solar-%ase electricity$ !ile !or %ankru#tcy in *99*& (ccoring to 6ewton
0ecker$ Lu<"s chairman o! the %oar$ an other investors$ the emise o! the alreay
meager ta1 creits$ eclining !ossil !uel #rices$ an the %leak #ros#ects !or !uture
assistance !rom %oth !eeral an state governments rove investors to withraw
!rom the #ro3ect& (s 0ecker conclue$ )The !ailure o! the worl"s largest solar
electric com#any was not ue to technological or %usiness 3ugment !ailures %ut
rather to !ailures o! government regulatory %oies to recogni<e the economic an
environmental %ene!its o! solar thermal generating #lants&)
-ther solar #ro3ects met with similar !inancial !ailure& ;or e1am#le$ two #lants that
em#loye the tower #ower conce#t$ .ison"s *,-megawatt #lant in :aggett$ /ali!&$
an a ?,-megawatt !acility %uilt in Joran #er!orme well es#ite o#erating on a
much smaller scale an without Lu<"s avantages o! heavy initial ca#ital investment
an a lengthy trial-an-error #rocess to im#rove e!!iciency& Still they were assesse
as too costly to com#ete in the intense conventional !uel market&
(lthough some o! our %rightest engineers have #rouce some e1em#lary solar
#ower esigns uring the #ast =5 years$ their work re!lects a is3ointe solar energy
#olicy& Ha the !inings o! the early solar #ioneers an the evolution o! their
machinery %een more closely scrutini<e$ #erha#s %y :e#artment o! .nergy o!!icials
or some other oversight committee$ contem#orary e!!orts might have !ocuse on
%uiling a new in!rastructure when social an #olitical attitues were more rece#tive
to solar technology& Rather than reiscovering the technical merits o! the various
systems$ we might have %een %etter serve %y reviewing history$ selecting a
relatively small num%er o! #romising systems$ an com%ining them with
contem#orary materials an construction techni2ues& Reinventing the wheel when
only the irection o! the cart seems sus#ect is certainly not the %est way to reach
one"s estination&
4hile the %est #erio to make our energy transition may have #asse an though
our energy !uture a##ears sta%le$ the #ro%lems that initiate the energy crisis o! the
*9+,s have not isa##eare& Inee$ the insta%ility o! -P./ an the recent success
in the Hul! 4ar merely create an arti!icial sense o! security a%out #etroleum
su##lies& 4hile we shoul continue to evelo# clean$ e!!icient #etroleum an coal
technology while our #resent su##lies are #lenti!ul$ this a##roach shoul not
ominate our e!!orts& (lternative$ renewa%le energy technologies must eventually %e
im#lemente in tanem with their !ossil-!uel counter#arts& 6ot oing so woul sim#ly
#rovie an e1cuse !or maintaining the status 2uo an %eg !or economic isru#tion
when reserves run low or #olitical insta%ility again eru#ts in oil-rich regions&
Towar that en$ we must change the #revailing attitue that solar #ower is an
in!ant !iel %orn out o! the oil shocks an the environmental movement o! the #ast
=5 years& Such misconce#tions lea many to assert that %e!ore solar #ower can
%ecome a via%le alternativeI the inustry must !irst #ay its ues with a !air share o!
technological evolution&
Solar technology alreay %oasts a century o! RJ:$ re2uires no to1ic !uel an
relatively little maintenance$ is ine1hausti%le$ an$ with ae2uate !inancial su##ort$ is
ca#a%le o! %ecoming irectly com#etitive with conventional technologies in many
locations& These attri%utes make solar energy one o! the most #romising sources !or
many current an !uture energy nees& (s ;rank Shuman eclare more than 7,
years ago$ it is )the most rational source o! #ower&)