“But there is a big concern that the economics of it might kill the industry in the meantime. Once the cost of energy gets beyond a certain point, our business model is gone.” New Zealand Gourmet production director for protected crops Roelf Schreuder says gas is a big concern and expensive. “On one of our sites, we went back to coal for the time being as, when combined with transport costs and line fees, it’s cheaper than gas. For the future, we are looking at a hybrid model of gas and solar energy. The plan is to set up a solar farm for power supply and make a combination of immersive heat, heat pumps and evacuated pipes. “The issue will be having no carbon dioxide available for the crop when excluding gas. Liquid carbon dioxide is being imported now Marsden Point has closed, and has become very expensive.”
All of the extra electricity required will have to come from coal. Where else will it come from? No gas. No more hydro. Coal will have to be it, which has nearly twice the carbon dioxide output of natural gas Electrical heat pumps are among the options to allow glasshouse operators to move away from carbon fuels. However, Neville Stocker, technical director for PGO Horticulture, which specialises in hydroponics for covered crops, says fitting electrical heat pumps to replace gas, coal or diesel fuelled boilers is not only relatively uncommon but likely to be expensive. “There would be a high cost to change the system, and many properties will not have a power feed of sufficient size to carry the current needed. Greenhouses are often close together, and so whole areas may not have the required infrastructure to power these operations. “All of the extra electricity required will have to come from coal. Where else will it come from? No gas. No more hydro. Coal will have to be it, which has nearly twice the carbon dioxide output of natural gas.” Meanwhile, Firstgas, a natural gas reticulator with around 7,000km of gas pipeline in the North Island, is predicting a move to a 20 percent hydrogen and natural gas blend by 2030, and a complete move to hydrogen by 2050. Hydrogen has nearly three times the calorific (heat) value per quantity (kg) compared with natural gas. However, making hydrogen requires splitting water in a process called electrolysis, and this requires electricity.
09 238 0770 021 959 948 nevoda@hyper.net.nz 70 Tuakau Road PUKEKOHE NZGROWER : MAY 2022 31
