Stor­age for clean en­ergy

Cosmos - - Contents - ALAN FINKEL is an elec­tri­cal en­gi­neer, neu­ro­sci­en­tist and the chief sci­en­tist of Aus­tralia.

Re­ly­ing on clean en­ergy means we need a big in­vest­ment in en­ergy stor­age, but the size of the num­bers are daunt­ing. MY NEW FAVOURITE num­ber is US$5 tril­lion.

It emerged from a back of the en­ve­lope cal­cu­la­tion. Batteries, such as the new Tesla Pow­er­wall are an ex­cel­lent so­lu­tion to the prob­lem of stor­ing re­new­able en­ergy. We need that stor­age for times when there is no wind and no sun. But how much stor­age does the world ac­tu­ally need? It turns out to be a lot. My re­cent cal­cu­la­tion was sober­ing. Imag­ine if you took all the batteries pro­duced in 2014 for phones, lap­tops and cars and in­stead used them to pro­vide backup for the global elec­tric­ity sup­ply. They’d keep the world run­ning for just nine sec­onds!

That’s not much use. To cope with the win­ter dol­drums (when you face con­sec­u­tive cloudy days with lit­tle or no wind) you would ideally want to have 10 days’ backup, a scale up by a fac­tor of 100,000.

As­sum­ing that the price per kilo­watthour of bat­tery falls to be­low US$100, US$5 tril­lion is the dol­lar value of batteries that we would need to man­u­fac­ture each year for 10 years in or­der to en­sure 10 days of bat­tery backup for the global elec­tric­ity grid.

That’s tak­ing into ac­count that man­u­fac­tur­ers such as Tesla, LG and Sam­sung would build gi­ant fac­to­ries and drive the cost of batteries down sharply.

Yes, $5 tril­lion sounds daunt­ing. But the en­ergy in­dus­try is ac­cus­tomed to such fig­ures.

In Jan­uary 2016 Bloomberg New En­ergy Fi­nance re­ported that global in­vest­ment in new clean en­ergy is ex­pected to grow to more than US$5 tril­lion by 2030, hav­ing reached a record US$329 bil­lion in 2015.

And in May 2015 the In­ter­na­tional Mone­tary Fund re­ported that global fos­sil-fuel sub­si­dies – money forked out by gov­ern­ments to help the in­dus­try – are dra­mat­i­cally higher than pre­vi­ously es­ti­mated, sitting at US$5.3 tril­lion (6.5% of global GDP) per year.

When a prob­lem is big, all the more rea­son to in­vest heav­ily in the so­lu­tion. And the in­vest­ment has to hap­pen at scale.

The roll-out of stor­age sys­tems has al­ready be­gun, but now is the time to mas­sively ramp up the ef­fort. Ar­guably sub­si­dies given for gen­er­at­ing elec­tric­ity – whether through re­new­ables or fos­sil fu­els – would be bet­ter shifted to nur­tur­ing tech­nolo­gies for stor­ing elec­tric­ity.

Of course, there is never only one so­lu­tion, and bat­tery backup will op­er­ate along­side hy­dro­gen stor­age, pumped hy­dro­elec­tric stor­age, so­lar ther­mal stor­age, and high-volt­age trans­mis­sion lines to move elec­tric­ity from windy re­gions and sunny spots to where it is needed.

In ad­di­tion to meet­ing the prob­lem head on, we can re­duce its scope. We need to de­sign our ve­hi­cles, homes, of­fices and fac­to­ries to use less en­ergy in the first place. We need to do this at scale through­out our global econ­omy, not just in a few show­case build­ings.

Not ev­ery­thing can be scaled to the de­sired ca­pac­ity. Even if we put so­lar on ev­ery suit­able dwelling, we would only pro­duce about 8% of our elec­tric­ity re­quire­ments. On the other hand, lo­cat­ing large-scale gen­er­a­tors in re­mote ar­eas could de­liver a lim­it­less amount of so­lar and wind en­ergy.

Ev­ery year the rate of de­ploy­ment of so­lar en­ergy has ex­ceeded ex­pec­ta­tions. Like Moore’s law for com­puter power, the amount of so­lar de­ployed world­wide has dou­bled roughly ev­ery two years for the past two decades. If it con­tin­ues for an­other two decades, we will be pro­duc­ing all the en­ergy we need from the Sun.

Num­bers like $5 tril­lion are not a rea­son to be daunted. They help us un­der­stand the scale of the chal­lenge and are a call to arms.


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