Wood energy

New technology is turning sludge from waste water into valuable bio-fuel with environmental and financial benefits for a Southland meat processing plant.

It's a bubbling fluidised bed boiler, well-proven overseas for its ability to handle low quality fuels. The 8.5MW unit was installed at Silver Fern Farms' Finegand plant by Energy For Industry under a build, own, operate agreement.

Ernslaw Bio-Energy's new mobile wood chipper means the Central Otago company is well-placed to take advantage of an expected increase in the use of wood-chip boilers.

The company bought the $250,000 German-made Heizohack HM10-500 KT chipper and the John Deere 7530 tractor which powers it in 2008 with the help of a business grant from the Energy Efficiency and Conservation Authority.

The University of Otago's Property Services division oversees the maintenance of campus buildings and grounds as well as new building construction. As the unit that keeps the University's campuses functioning year round, Property Services' energy use can be intensive. So when they were considering a heating upgrade, one of the key drivers was the ongoing cost of power. Renewable energy was the preferred option. But like any other organisation with limited budget, the final solution needed to make good business sense.

Wigram Lodge installed a wood-chip boiler - and in the process reduced energy costs and improved tenant comfort. Wigram Lodge is saving up to $52,000 and has reduced emissions by 146 tonnes per year.