The Economist - UK (2022-04-02)

36 United States TheEconomistApril2nd 2022

DroughtinCalifornia

Hold the salt

C

arlsbadstatebeach is aSouthern

Californiaidyll.Palmtreesadornthe

cliffsabovethesand,andsurferspaddle

outforthewaves.Fromthebeachitisim­

possibletotellthatahugedesalination

plantnothalfa mileawayissuckinginsea­

water to produce 50m gallons of new

drinkingwatereachday.Itisthelargestin

America—fornow.Soonitmaysharethat

titlewitha proposedsisterplant 60 miles

(97km)northinHuntingtonBeach.Buton­

lyif thatoneisbuilt.

PoseidonWater,thedeveloperthatalso

builttheCarlsbadplant,firstproposedthe

HuntingtonBeachfacilityinthe1990s.But

ithastakenthecompanymorethantwo

decadesto persuade Californians ofthe

plant’snecessity.ManyOrangeCountyres­

identsremainunconvincedorevenhostile

totheidea.Nowthefirmiswaitingfora fi­

nal permit from the California Coastal

Commission. Without it, Poseidon says

theprojectisdeadinthewater.

The fight in Huntington Beach has

sparkeda widerdebateoverwhatrolede­

salinationshouldplayinpreparingCali­

forniaforadrierfuture. Arecentstudy

foundthatthecurrentdroughtisthedriest

22­yearperiodthesouth­westhasseenin

atleast1,200years.Climatechangehasdi­

minishedsnowpackintheSierraNevada

mountains, shrivelling therivers which

feedCalifornia’sreservoirs.Thestatere­

centlytoldfarmsandcitiestheywouldre­

ceiveonly5%oftheirnormalallocation

fromtheStateWater Project,aseriesof

dams,canalsandpipelines.Mightdesali­

nationhelpmakeupthedifference?

Theargumentsagainstdesalinationare

wellknown. Environmentalistsfret that

theplants’intakesystemsandthesalty

brinetheydischargebackintotheocean

harm marine life. The reverse­osmosis

processusedtoseparatethesaltfromthe

waterisenergy­intensive.Anddesalina­

tionisthemostexpensiveoptionamong

alternative water sources. An analysis

fromthePacificInstitute,a think­tankin

Oakland,estimatesthatthemediancost

fora bigseawater­desalinationprojectis

$2,100peracre­footofwater(anacre­foot

isabout1,230cubicmetres).Largewater­

recycling projects, the next­priciest op­

tion,costroughly$1,800anacre­foot.

Tounderstandthecostsandbenefitsof

desalinationinpractice,looktoSanDiego.

Investing in desalination seemed pre­

scientwhentheSanDiegoCountyWater

Authority(sdcwa),whichsupplies  water

to3.3msouthernCalifornians, began plan­

ningtheCarlsbadplantin1998,  for  two

mainreasons.First,whenrivers  run  low,

muchofCaliforniacantapunderground

aquifers for drinkingwaterand  agricul­

ture.Butthefarsouth­western  corner  of

Californiadoesnothavealarge  ground­

waterbasin,meaningtheregion  long  re­

liedonwaterimportedfromelsewhere. 

Second,a severedroughtstarting in the

late1980scutthecounty’swater supply by

31%, says Sandra Kerl, sdcwa’s  general

manager.Thosecuts(andanacrimonious

relationshipwithwaterofficials in Los An­

geles, who controlled local  supplies)

scaredlocalmanagersintoexploring alter­

nativewatersources,suchasdesalination,

topreventrationinginfuture.  Today,  10%

ofthecounty’swatercomesfromtheCarls­

badplantandSanDieganscanbreatheeas­

ierintimesofdrought.

Nowconsiderthecosts.Overthepast

decadewaterpriceshaverisenfasterinSan

Diegothanin LosAngeles.KelleyGage,

sdcwa’s directorof waterresources, ar­

guesthatrateswillclimbacrossthestateas

othercitiesinvestinrecyclingorshoring

upleakyinfrastructure.Desalinatedwater

is alsousedinefficiently. Pristine water

fromtheCarlsbadplantentersa central­

isedplumbingsystemjustliketreatedwa­

terfromtheColoradoRiver,forexample.

“Utilitieshavetothinkaboutthefactthat

thiswateristoogoodtobeflusheddown

toiletsandusedforwateringlawns,”says

NewshaAjami,a waterexpertattheLaw­

renceBerkeleyNationalLaboratory.

AsSanDiegowasscramblingtodiversi­

fyitswatersupply,demandwasdecreas­

ing.Thankstoconservationefforts,per­

personwateruseinCalifornia’sbigcities

hasdeclinedsince 2000 evenaspopula­

tionshavesoared.SomeSanDieganswon­

derif theirexpensiveplantwasnecessary.

Desalination makes more sense in

somepartsofCaliforniathanothers.The

Golden  State’s  water  wonks  point  to  the

central  coast,  which  often  suffers  from

drought.  Adrian  Covert,  vice­president  of

public  policy  at  the  Bay  Area  Council,  a

business  association,  suggests  Marin

County should also consider desalination.

A wealthy county just north of San Francis­

co, Marin has the need—it is dependent on

local rainfall—and the cash to invest. 

Pipe dreams

Water­policy nerds favour desalination as

a last resort, preferring conservation, recy­

cling  and  capturing  stormwater.  “It’s  all

about  lawns  and  leaks,”  says  Felicia  Mar­

cus,  a  former  chair  of  the  California  State

Water  Resources  Control  Board.  Yet  most

experts agree that desalination could play

a larger role in the state’s water mix as tech­

nology improves. “Desalination is ripe for

innovation,” says Peter Fiske, also of Law­

rence  Berkeley  National  Lab.  Researchers

are studying how to make plants more flex­

ible  through  automation,  whether  the

brine  discharged  back  into  the  ocean  can

be used for something, and the economics

of desalting water using solar power. 

California is not the only state mulling

desalination.  Doug  Ducey,  Arizona’s  Re­

publican governor, wants to invest $1bn in

the  technology.  The  Biden  administration

has allocated $250m in funds from the bi­

partisan  infrastructure  law  for  desalina­

tion  projects  (a  proverbial  drop  in  the

bucket).  If  and  when  desalination  does

take off, Ms Marcus warns that technology

alone  cannot  “drought­proof”  the  state:

“The  idea  that  you  can  somehow build

enough facilities to support urbanCalifor­

nia through desal is a pipe dream.”n

C ARLSBAD

The promise and pitfalls of seawater desalination

Water, water, everywhere

PACI F I C

OCEAN

SanFrancisco

Marin

County Nevada

Arizona

LosAngeles

UNITED

STATES

San

Diego

Orange

Carlsbadplant

Huntington

Beachplant*

California

Oregon

SI

ER

RA

NE

VA

DA

MO

UN

TA

IN

S

*Proposed

Source:California

WaterBoards

2 km