Power from bac­te­ria

New pro­cesses to har­ness al­gae’s eletrodes and methane’s en­ergy.

The Witness - Wheels - - MOTORING -

RE­SEARCHERS this week an­nounced two ad­vances in power gen­er­at­ing that may yet im­pact on trans­port.

At the Con­cor­dia Univer­sity in Mon­treal, re­searchers have in­vented a power cell that har­nesses the elec­tric­ity cre­ated dur­ing the nat­u­ral pro­cesses of pho­to­syn­the­sis and res­pi­ra­tion in blue-green al­gae.

And at the In­sti­tute of Ad­vanced Sus­tain­abil­ity Stud­ies (Iass) and Karl­sruhe In­sti­tute of Tech­nol­ogy (Kit) have de­vel­oped a process that ex­tracts the en­ergy con­tent of methane, in the form hy­dro­gen, with­out pro­duc­ing car­bon diox­ide.

The jour­nal Tech­nol­ogy quotes Con­cor­dia engi­neer­ing pro­fes­sor Muthuku­maran Packirisamy: “By tak­ing ad­van­tage of a process that is con­stantly oc­cur­ring all over the world, we’ve cre­ated a new and scal­able tech­nol­ogy that could lead to cheaper ways of gen­er­at­ing car­bon­free en­ergy.”

Blue-green al­gae, which is ac­tu­ally cynobac­te­ria, is also touted as pos­si­ble source of bio­fuel.

The Con­cor­dia group re­port their pro­to­type pho­to­syn­thetic power cell mea­sured open-cir­cuit volt­age of up to 993 mil­li­volts, while a peak power of 175 mi­crowatts was ob­tained un­der an ex­ter­nal load of 850 ohms.

Packirisamy hopes the pho­to­syn­thetic power cells could soon be used to power mo­bile de­vices and com­put­ers and per­haps even­tu­ally be­come a ma­jor source of en­ergy world­wide.

In the U.S., mean­while, re­searchers are look­ing at cheaper ways to milk methane for its en­ergy (hy­dro­gen) to meet the Amer­i­can’s de­mand for nat­u­ral gas, which ac­counts for over 28% of U.S. en­ergy consumption.

Methane gases are pro­duced wher­ever plant ma­te­ri­als are rot­ting or have rot­ted, such as coal mines, but also by live­stock, rice pad­dies and even ter­mites.

Kit adapted an old process called “methane crack­ing,” which sep­a­rates the hy­dro­gen and car­bon mol­e­cules at tem­per­a­tures of over 750° C, by de­sign­ing a small new re­ac­tor de­sign based on liq­uid metal tech­nol­ogy, and made of quartz and stain­less steel.

Pro­fes­sor Thomas Wet­zel of Kit, said the re­ac­tor pro­duces hy­dro­gen with a 78% con­ver­sion rate at 1 200° C, and can run con­tin­u­ously for two weeks.

Kit re­searcher Ste­fan Stueck­rad said the team ex­pect to spent un­til 2018 to re­search and de­velop an in­dus­trial pro­to­type for a mod­u­lar re­ac­tor, which could be scaled by sim­ple mul­ti­pli­ca­tion.

Stueck­rad added that the en­ergy ef­fi­ciency of the process “has been eval­u­ated as slightly higher than con­ven­tional steam re­form­ing of nat­u­ral gas and about 20% higher than coal gasi­fi­ca­tion” — as­sum­ing both em­ploy car­bon cap­ture and stor­age.

The team’s re­search showed that methane crack­ing is com­pa­ra­ble to wa­ter elec­trol­y­sis, in re­gards to CO2 emis­sions per unit of hy­dro­gen, and more than 50% cleaner than steam methane re­form­ing tech­nolo­gies.

Pre­lim­i­nary cal­cu­la­tions re­veal that the tech­nol­ogy could achieve costs of €1,90 to €3,30 (R29 to R50) per kilo­gram of hy­dro­gen (at cur­rent Ger­man nat­u­ral gas prices).

Crit­ics how­ever point out Kit’s new crack­ing process needs huge amount of en­ergy, and un­less so­lar power is used to make this power, their process will lead to CO2 emis­sion be­ing gen­er­ated up­stream.

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