20 | REGIONAL Ecogas NZ T T Virginia Wright Making good use of green waste Ecogas is owned by Pioneer Energy, which in turn is co-owned by Central Lakes Trust and Totara Investment. Since 2022, Ecogas Ltd has been successfully diverting organic waste from landfill and converting it into renewable gas in New Zealand’s first commercial-scale biogas production facility. Located in Reporoa, halfway between Rotorua and Taupō, Ecogas is owned by Pioneer Energy, which in turn is co-owned by Central Lakes Trust and Totara Investment. At the core of Ecogas’s success is the anaerobic digestion (AD) process, which converts the organic waste into renewable gas, electricity and heat, by consuming the exact same greenhouse gases that are created as it decomposes. Otherwise, it would be adding to the greenhouse gases that are now widely accepted as contributing to earth’s rising temperatures. New Zealand sends thousands tonnes of organic waste to landfill every year, where it emits a steady stream of greenhouse gas (itself a form of energy) as it decomposes.. The anaerobic digestion process keeps those emissions out of the atmosphere. “We harvest the energy, the greenhouse gas, from the food waste as it decomposes and turn it into fuel, essentially,” says Ecogas chief technical officer, Alzbeta Bouskova. “Compared to landfills that inherently release greenhouse gas emissions, we turn the organic waste into a high-value product that has the potential to make a critical difference to the reliable gas supply New Zealand needs.” A process engineer originally from the Czech Republic, Alzbeta completed her PhD in the anaerobic digestion process in Sweden before bringing her expertise to New Zealand in 2009. “We generate upwards of 100,000 GJ of renewable gas per year into the network, which is brought to market through NOVA Energy. “We sell the gas to them and they on-sell it to their customers. It’s enough to provide gas to the whole of the domestic and commercial gas market in the Taupō region,” says Alzbeta. Businesses and entities are increasingly taking responsibility for diverting their organic waste from landfill to be converted into this high-value product, with all the environmental, economic, and social benefits that come with it. As a result, after four years Ecogas is running near capacity and is looking to increase its intake of organic waste from 75,000 tonnes to 100,000. It’s still a long way from taking all of New Zealand’s organic waste, or making an appreciable difference to the country’s gas needs, but with the Reporoa plant acting as a sort of proof of concept, there is now a second plant being built in Hornby in Christchurch, which will take all the organic waste that was formerly being made into compost by the Christchurch City Council. The contents of Christchurch’s green bins will go through the same anaerobic digestion process to produce biogas. That will then be used on-site to make a new product using the biomass fibre, which is another byproduct of the process, and which will be made into brickettes to supply the industrial heating market in Canterbury. Coal burners are still used commercially and industrially in some factories, hospitals, and industrial processors, but for the last decade have started being converted to electricity or biomass boilers, says Alzbeta. “So we’re doing two things. We’re capturing the greenhouse gases and preventing them from being emitted into the atmosphere, and we’re supplying the renewable fuel for those biomass boilers.” As far as Alzbeta is concerned, scaling up with more plants around the country converting more of our decomposing organic waste into renewable energy is an obvious choice. “It’s real and everybody should get on board,” she says. “The Christchurch City Council had the vision to see the benefits this technology can deliver to the Canterbury region. “By contracting to supply us with all of the green bin waste they’re supporting us in building something that the whole region will benefit from.” Ecogas will bring another byproduct of the process to the Christchurch market with their nutrient- and trace element-rich fertiliser, which has already been embraced by farmers around Taupō and Rotorua. IIt’s a win for the council, for the environment, for the planet and for everyone making good use of their green bin in Christchurch.
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