Biogas plant for Chch planned?

Press, 6 February 1982, Page 1

Biogas plant for Chch planned?

The Christchurch Gas Company may set up a biogas plant on the outskirts of Christchurch, using wheat and barley straw to make methane. The chairman of the Gas Company, Mr H. W. Revell, said that discussions were very much in their infancy and as yet nothing had been put down on paper. “There is a board meeting on February 15 where the idea will be discussed fully for the first time. It is still a long way down the track and I will be in a better position to comment after the meeting,” Mr Revell said. North Canterbury wheat and barley farmers appear interested in the idea.

The vice-president of the agriculture section of the North Canterbury Federated Farmers, Mr G. E. J. Hutton, said a majority of farmers would be in favour of supplying the biogas plant with wheat and barley straw if it was economically worth while. Mr Hutton made his comments after the executive of the agriculture section had heard an outline of the Gas Company’s proposal from a consulting engineer, Mr H. E. Archer, of Steven Fitzmaurice and Partners, of Christchurch.

Mr. Archer and an agricultural consultant, Mr D. R. Haslam, of W. A. N. Brown and Associates, had asked the meeting of Federated Farmers to answer questions on the willingness of farmers

to supply straw to such a plant, the prices the plant would need to pay, the preferred form of contract, and the willingness of farmers to store straw on farm to spread supply. The response from the farmers at the meeting was generally favourable to the Gas Company’s proposal.

Mr Archer outlined the Gas Company’s proposal to establish a biogas plant on the outskirts of Christchurch, probably at Hornby, and pipe the methane produced through the Gas Company’s existing mains to Moorhouse Avenue where it would be compressed and sold as compressed natural gas. The Hornby plant would be an anarobic digester which could run on all types of vegetable matter, but wheat and barley straw were being investigated because of their availability in North Canterbury.

Mr Haslam said that within a 70km range of Hornby about 100,000 tonnes of straw was produced each harvest.

The proposed plant would use 12,000 tonnes a year of such straw. The consultants said that Meadow Mushrooms, Ltd, of Prebbleton, bought 4000 tonnes of straw each year at about $42 a tonne, or $l4 for a round bale. Farmers were also paid $2 a bale extra for storing the straw on-farm until after June. Some of the senior officials of Federated Farmers in

North Canterbury commented favourably on the Gas Company’s proposal.

The chairman of the Dominion agriculture section council, Mr N. Q. Wright, (Sheffield) said he welcomed the plan. He proposed a sub-com-mittee of the provincial agriculture section be set up to talk further with the Gas Company and its consultants. “The problem of straw as a by-product of cropping is one that occurs all round the world,” he said.

The provincial president of Federated Farmers, Mr A. L. Mulholland (Darfield) said the proposal was a logical and sensible approach to a waste product which is often put up in smoke.

He said he had learnt on a recent visit to the United States that 4kg of straw could produce as much energy as Ikg of oil. In reply to a question on whether removing the straw from paddocks would seriously deplete the soil, Mr Mulholland said 80 per cent of soil depletion after a crop was in the grain and only 20 per cent in the straw.

Another executive member of the agriculture section, Mr P. S. Phillips (Rangiora) said straw was worth between $25 and $3O an acre net to him. Other comments from the farmers to the consultants raised the value of stubble burning and ploughing the stubble back into the land to. aid in soil structure and water retention. .