How cutting winter heating bills helped one business stay cool as a cucumber in summer.

Energy costs put the heat on energyintensive growing operations, but cool thinking can generate innovative solutions and a raft of benefits.

If you’re a grower, you’ll know that reducing energy use without affecting crop yield or increasing production costs is of major importance to horticulture businesses. It’s a challenge, but it can be done. Renatus Horticulture has been able to achieve a win-win – increasing productivity and reducing fuel costs – through an energy efficiency investment in its Waikato-based greenhouses. Owner Gary Geurts installed a dual energy-conserving thermal screen and shade screen system at the 6000 square metres of greenhouses that service his cucumber-growing business at Cambridge. The initiative has reduced the business’s energy costs by around $25,000 per year - and it has also boosted summer crops by about 10%. “Cutting heating costs in the winter was the main driver for installing the screens, alongside the flexibility of being able to provide shade when it is needed in summer. Rather than whitewashing the glasshouses, which provides constant shade, we now have shade when we need it. “In the summer we get the shade benefits and in winter we get the energy-saving benefits. We are making energy savings for around six months of the year.” The innovative screens work like curtains, covering the entire glasshouse area, and are controlled by computers according to outside light and temperature. “The shade is invaluable in summer, then coming into autumn it is flexible when you have cool days but still some very hot ones,” said Mr Geurts. “Once you get into winter and there are frosts we save around 50% on energy costs on a cold night. Our pipes used to run at 70-80 degrees on a frosty night, now it’s 55-60 degrees.” The lower the temperature the less coal is needed to heat the glasshouse resulting in lower carbon emissions. It is estimated that in climate controlled greenhouses, energy costs are around 20% of expenses, or 15%-18% of revenue, making growers highly vulnerable to rising energy costs and additional energyrelated taxes. Mr Geurts installed the screen system with support from an EECA grant and estimates payback will be six to seven years. Instead of writing fuel off as a fixed cost Renatus Horticulture has turned the problem into a solution that delivers benefits all year round, in the form of increased productivity, reduced environmental impact, and a much more pleasant place to work.