An automaker takes a creative approach to renewable energy

Audi’s A3 Sport­back TCNG is being billed as the next big thing in sus­tain­able mobil­i­ty. The car runs on what Audi is call­ing “e-gas,” a sub­stance that is more or less equiv­a­lent to nat­u­ral gas and is cre­at­ed in a com­pli­cat­ed chem­i­cal process explained here. Between its e-gas capac­i­ty and back­up use of reg­u­lar old gaso­line, the A3 Sport­back TCNG has a trav­el­ing range of almost 800 miles.

Per­haps most sig­nif­i­cant­ly, Audi’s e-gas tech­nol­o­gy can serve as a stor­age sys­tem for excess ener­gy gen­er­at­ed from renew­able sources. One of the biggest prob­lems with solar ener­gy and wind ener­gy is that the­se meth­ods of cap­tur­ing pow­er fluc­tu­ate over the course of a day and a year. Solar pow­er peaks when sun­light peaks (mean­ing both mid­day and sum­mer­time), and wind pow­er peaks on windier days and windier sea­sons. Of course, ener­gy use also peaks. Peo­ple use more ener­gy imme­di­ate­ly after com­ing home from work, for exam­ple, when they are turn­ing on all of their house­hold appli­ances, than they do in the mid­dle of the night, when many of the­se appli­ances are turned off.

How­ev­er, the peaks of ener­gy pro­duc­tion and ener­gy usage rarely over­lap. When sun­light peaks in the mid­dle of the day, most peo­ple are too busy work­ing (albeit, often on lap­tops and smart­phones) to turn on their dish­wash­ers, tele­vi­sions, and lights at home. This dis­par­i­ty in peak times wouldn’t be much of a prob­lem, except that the elec­tric­i­ty gen­er­at­ed from the­se renew­able sources is often dif­fi­cult to store in the short term, and near­ly impos­si­ble to store in the long term. The result is that much of the hard work that our solar pan­els and wind­mills do to gen­er­ate pow­er goes to waste as the elec­tric­i­ty goes unused and van­ish­es, hav­ing been cap­tured only briefly.

As described in their press release:

…[Audi begins] with wind, water and car­bon diox­ide sourced from a bio­gas plant. The end prod­ucts are renew­ably gen­er­at­ed eco-electricity…hydrogen …and syn­thet­ic methane (Audi e-gas) which can pow­er vehi­cles like the new A3 Sport­back TCNG that will launch in 2013.”

Prob­a­bly the com­pelling ques­tions in this process are: how many watts of pow­er are required to pro­duce a gal­lon equiv­a­lent of syn­thet­ic methane? And, is this method of stor­ing sur­plus elec­tric­i­ty more or less effi­cient than oth­er meth­ods, like bat­ter­ies?

Pho­to: Audi​.com

The impli­ca­tions could be big. Audi’s facil­i­ty, and sim­i­lar facil­i­ties like it, could store the excess elec­tric­i­ty pro­duced by renew­able sources, sav­ing it from going to waste by con­vert­ing it to e-gas.

(In the Audi process, the CO2 comes from a point source, at a pow­er­plant; in the­o­ry, a sys­tem like this could also make use of CO2 cap­tured from the air, as in Klaus Lackner’s mod­el.)

E-gas would then enter the nat­u­ral gas net­work, where it could be used, stored, or lat­er con­vert­ed back into elec­tric­i­ty. This process could rev­o­lu­tion­ize renew­able ener­gy, mak­ing the­se green sources more effi­cient and thus more appeal­ing to com­pa­nies and con­sumers. Thus, whether or not the A3 Sport­back TCNG is suc­cess­ful from Audi’s per­spec­tive, the e-gas tech­nol­o­gy that is being devel­oped to pow­er it will cer­tain­ly go down as a major con­tri­bu­tion to a green­er future.

Audi’s Werl­te facil­i­ty will be com­plet­ed and opened for oper­a­tions in 2013, and the A3 Sport­back TCNG will launch the same year.