BOVINE POWER PLANTS

Element - - Primary Industry -

An­other pos­si­ble growth area be­ing con­sid­ered is bio­gas gen­er­a­tion on some of the coun­try’s larger dairy farms. How large a farm needs to be to make this vi­able is still up for de­bate. A re­port by Waste So­lu­tions sug­gested rul­ing out any farm with less than 400 head of cat­tle, which would leave about half the na­tion’s 11,600 herds as pos­si­ble can­di­dates.

But other es­ti­mates sug­gest an even larger herd of about 1000 cat­tle would be needed to pro­duce an eco­nom­i­cally vi­able amount of waste, of which there are about 400 pos­si­bles around the coun­try. A lot de­pends on how ef­fi­ciently the waste might be col­lected.

Cur­rently it is es­ti­mated that dairy farms only col­lect some­thing like a fifth of it, with the rest be­ing plopped out in the pad­docks. But the amount of waste pro­duced by the larger herds is dif­fi­cult and costly to deal with. This pro­vides an­other in­cen­tive to use a bio­gas di­gester, es­pe­cially if cows are in­creas­ingly fed on feed pads or put on win­ter­ing pads there could be more waste avail­able but, most im­por­tantly, it is put in one place and not spread around the pad­docks.

But, for the time be­ing, Fed­er­ated Farm­ers Dairy chair­per­son, Lach­lan McKen­zie, is scep­ti­cal. He has had his own dairy op­er­a­tion as­sessed and found the amount of elec­tric­ity he would pro­duce from a bio­gas sys­tem would be only roughly the same as the amount of en­ergy it would take to run it. In the mean­time, he says, the bulk of the ma­nure from New Zealand’s dairy farms is re­cy­cled any­way, by the cow drop­ping it out in the pas­ture to grow more grass. But he re­mains open to the prospect if the tech­nol­ogy can be im­proved, and feels other farm­ers would be, too.

“If a farmer can spend a dol­lar and get a dol­lar fifty back they are sold,” he said.

The same goes for the rest of us, which is why it’s a great time to take a fresh look at poo.

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