Where there's muck there's brass

This old Yorkshire adage should be followed by the New Zealand and other country dairy industries to save on costs, provide energy and clean up the environment. As the global recession bites, New Zealand and other country dairy farmers will come under tougher cost pressures from increased electricity charges and environmental compliance. One solution is to use dairy waste to raise heat and power. Instead of taking fright at New Zealand greenhouse gas (GHG) emission rules, farmers can turn the situation to their advantage. New Zealand has a particular problem with methane, as 49 % of its GHG comes from grazing animals – mostly from their gut and out of their mouths and a the rest from the back end.

The technology involved comes off the shelf. It is in widespread use in the United States, being taken up in Europe and is now taking off in Asia. Any company which ‘cracks’ the packaging of a flexible system for dairy farms, will make a good living. Whanganui, where I live, and situated between large dairy regions, Taranaki and Manawatu, and having dairy farms of its own, could become a regional centre.

The technology works like this: dairy shed waste is flushed into a set of sumps; the grit is left to settle and then the waste is pumped into a digester. This produces methane gas from the waste, which is then burned to raise heat. It can also be burned in a small methane engine to generate electricity. Remote farms, using expensive diesel generators, can replace them. If a feed pad system is used, then more waste is collected while the cows are eating.

Here are the three wins:
• First, it allows farmers to manage their effluent better, including nitrous oxides. The process does not eliminate nitrogen, but manages it better.
• Second - it converts methane –20 times more powerful as a greenhouse gas than carbon dioxide – into useful energy.
• Third, in future, farmers will earn carbon credits for doing this. All political parties should be thinking about how to bring farmers into such a system early, to encourage the take up of biogas generation, now.

The Christchurch, NZ company, BioGenCool and Landcorp have a working prototype. Other trials have been conducted on middle sized dairy farms and several New Zealand companies are in talks with farmers to set up projects. Warwick Cutfield, technical director of Maunsell Engineering laid out the issues in a presentation to our Whanganui River Institute annual seminar back in February. Environutra, a start-up company is in discussions with dairy farmers in the region. The brass is in sight.