Com­mer­cial vi­a­bil­ity a prize catch

The Weekend Australian - Review - - Clean Energy - Derek Parker

RE­SEARCH into cap­tur­ing car­bon emis­sions has moved from the­ory to hard- headed com­mer­cial prac­tice, with large- scale car­bon cap­ture and stor­age likely in about eight years, ac­cord­ing to CO2CRC.

‘‘ We al­ready know a great deal about how to cap­ture car­bon diox­ide emis­sions from power sta­tions,’’ CO2CRC chief tech­nol­o­gist Barry Hooper said. ‘‘ In fact, we have the pieces of the puzzle to go from cap­ture at source to se­ques­tra­tion in an un­der­ground or un­der- seabed reser­voir. The fo­cus of our re­search now is to put those pieces to­gether in a way that is com­mer­cially vi­able.’’

He points to a ma­jor study by CO2CRC which shows the tech­ni­cal fea­si­bil­ity of cap­tur­ing about 90 per cent of the car­bon emit­ted from Vic­to­ria’s power gen­er­at­ing fa­cil­i­ties in the La­trobe Val­ley — about 50 mil­lion tonnes a year — and stor­ing it per­ma­nently un­der­ground deep be­low gas fields in the off­shore Gipp­s­land basin.

There have been sev­eral suc­cess­ful se­ques­tra­tion tests at var­i­ous sites around Aus­tralia and over­seas. The Sleip­ner off­shore gas pro­duc­tion fa­cil­ity in Nor­way, for ex­am­ple, se­questers about a mil­lion tonnes of car­bon a year and has been op­er­at­ing for a decade.

The prin­ci­ples of cap­ture are not new. The most com­mon meth­ods in­clude sol­vent ab­sorp­tion into chem­i­cals, mem­brane cap­ture, which uses lay­ers of poly­mers to sep­a­rate car­bon diox­ide mol­e­cules from waste emis­sions, and the use of solid sur­faces to re­move car­bon diox­ide in a process called ad­sorp­tion.

New ma­te­ri­als are be­ing de­vel­oped and tested all the time, es­pe­cially with ad­sorp­tion pro­cesses. CO2CRC re­searchers at Monash Univer­sity are cur­rently ex­am­in­ing ma­te­ri­als sim­i­lar to sil­ica gel. And tri­als have al­ready moved out of the lab­o­ra­tory with a new range of sol­vents be­ing tested at Vic­to­ria’s gi­ant Loy Yang A power sta­tion.

Cap­ture is only the first step in the process. The car­bon diox­ide is sep­a­rated to over 95 per cent pu­rity and then com­pressed into a high­den­sity fluid for trans­port to the se­ques­tra­tion site. The process is costly, not just in dol­lars but in the en­ergy re­quired. It could add as much as 35 per cent to the en­ergy needed to run a power sta­tion, as well as the en­ergy costs of liq­ue­fac­tion and trans­port.

‘‘ If it was ab­so­lutely re­quired, it would be pos­si­ble to set up a car­bon cap­ture and se­ques­tra­tion sys­tem quite quickly,’’ Hooper says. ‘‘ But as things stand, it would be ex­tremely ex­pen­sive, with con­sumers ul­ti­mately hav­ing to pay through much larger power bills. So we are look­ing at ways to re­duce the costs, from ma­te­ri­als and meth­ods used, to the es­tab­lish­ment of cap­ture fa­cil­i­ties and their in­te­gra­tion with ex­ist­ing equip­ment, to the en­ergy re­quired.

‘‘ We are very aware that there are still a lot of un­known fac­tors about the costs. We are watch­ing the de­bate over the car­bon trad­ing scheme very closely — that will be very im­por­tant for this area of re­search. An­other big part of the pic­ture is the reg­u­la­tory frame­work at state and com­mon­wealth lev­els.

‘‘ It is very use­ful, on the sub­ject of costs, to look at the in­tro­duc­tion of desul­phuri­sa­tion tech­nol­ogy, which was in­tro­duced as a reg­u­la­tory re­quire­ment in the 1970s to re­duce acid rain and pol­lu­tion. For power sta­tions this rep­re­sented a very sig­nif­i­cant out­lay, and in the first few years the cost was con­sid­er­ably more than pre­dicted.’’

How­ever, af­ter five years or so, the cost of the tech­nol­ogy be­gan to drop dra­mat­i­cally, as re­search was re­fined and desul­phuri­sa­tion be­came a reg­u­lar part of op­er­a­tions. Th­ese days, no one thinks about desul­phuri­sa­tion equip­ment as any­thing spe­cial, it’s just part of the process of gen­er­at­ing elec­tric­ity.

‘‘ In en­gi­neer­ing- based in­dus­tries, you see this pat­tern — large out­lays fol­lowed by con­sis­tent cost re­duc­tions — again and again. I ex­pect that we will see it in car­bon cap­ture and stor­age tech­nol­ogy as well.’’

Coal: Emis­sions and car­bon trad­ing are two chal­lenges fac­ing the La­trobe Val­ley

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