Case studies

In May 2008 Cashmere High School switched from coal to renewable wood energy to heat its site.

The new boilers produce around five times less particulate emissions than a typical school coal boiler. Carbon emissions have reduced by 216 tonnes per year. The wood-fired system is also 14% more efficient.

"There used to be soot and ash in the gutters. Now we just have clean, clean emissions," says Cashmere High support services manager Roger O'Regan.

Pacific Wood Products (PWP) installed Ecogate control systems on their extraction fans. Through the use of air flow control gates and a variable speed drive connected to each fan that adjusts to meet the actual workload, PWP reduced their energy use substantially.

Energy savings were immediate from week one. The system will be paid for in be just over 4 years, and long-term they benefit from lower energy bills. Equally important, PWP will cut its annual CO₂ emissions by 45 tonnes.

With its future at stake, New Zealand Foam Latex needed an economically viable and environmentally friendly fuel to produce steam needed to manufacture their products - all made from foam.

Coal was cheap, from $6.10/GJ. But emissions and the costs of mitigating them ruled it out. Diesel and LPG would cost over $30/GJ.

Wood was cost-effective and clean-burning. A variety of sources helped assure reliable supply - forestry hoggings, timberyard residues, left-over pallets and demolition, even dunnage reclaimed from shipping.

By adopting a suite of solutions to cut their per-kilometre fuel use, this company has improved its margins without the need for dramatic increases in cartage prices - and it has reduced emissions as well.

The key ways Winstone Aggregates achieved the savings was through reducing idling time, having covers on trucks at all times, reducing vehicle speed, tyre management and travel planning and management.