Pierre Gargiulo, general manager at JS Ewers, left, alongside Al Bates from Sollys Freight Service, with clean woodchips for their biomass boiler. Photo: Eloise Martyn.
Nearly two years ago, JS Ewers officially shut down its coal-fired heating system and activated a cutting-edge woodchip biomass boiler.
The change has not only transferred away from the use of coal use at the site but has dramatically reduced their CO2 emissions by 98 per cent, and when combined with other sustainability initiatives, cut 27,000 tonnes of CO2 annually from on-farm emissions.
“We’ve been impressed with the reduction and encouraged by the fact we’re making good use of a local waste product,” says Pierre Gargiulo, general manager at JS Ewers. The biomass boiler is used to consistently heat 10.5 hectares of glasshouses for optimal growing conditions for eggplant, capsicum, and tomato crops.
Here’s how it works, in simple terms. The boiler burns wood chips to create heat. This heat is used to heat water. The hot water is then circulated through pipes within the glasshouses. The heating systems maintains the ideal temperature for plant growth.
Large water tanks are between the boiler and the glasshouses. These tanks work like giant batteries, storing heat that can be used later when demand is higher, like overnight when the temperatures drop.
The temperature inside the furnace section is around 930°C, and although classified as an “unattended boiler”, it’s constantly monitored by an on-site maintenance team and protected by a network of alarms and safety systems. In the event of a malfunction, the system shuts down safely, posing no public risk - the only consequence being a potential drop in glasshouse temperatures.
The boiler components were manufactured in Austria, but the entire plant was assembled locally, which was a deliberate decision.
“We wanted to support local jobs but also ensure we had a team who understood the plant and who could respond to any repairs or issues,” Pierre says.
“We had good support from Tasman District Council, who were very supportive of the project, along with central government.
“Key in the project was AMK for structural engineering and design, IMB Construction Ltd, and Walker Engineering— they were instrumental in bringing it all together. One day, we had 50 different people working on site at once - and it worked,” he adds.
The fuel is wood chips made from forestry slash and is organised by Sollys Freight Service (Sollys), which brings in around 400 tonnes each week.
“It’s a good thing and it keeps us busy,” says longtime Sollys driver Al Bates, who previously delivered coal to JS Ewers.
“It was great to have Sollys involved from the start - they understand our energy needs,” Pierre adds.
The wood is sourced from OneFortyOne and is chipped directly into Sollys’ trucks and transported straight to the market garden.
“How OneFortyOne stacks their wood ready for chipping is excellent,” Pierre says.
“There’s very little mud or stones, thanks to them. The chip hopper has the capacity to hold enough fuel for about 4.8 days of burning.
“However, we usually choose not to fill it completely. Before the June/July weather events, that storage capacity proved to be a real advantage. Sollys filled the hopper while they could. It was a move that ensured we had enough fuel to keep running.”
The boiler was part of a five-year, staged process that included building a ring-main system—a network of large pipes distributing hot water across the site, along with constructing a boiler shed, installing a fuel handling system, and integrating everything into the existing infrastructure.
“Biomass boilers aren’t a new concept,” Pierre states.
According to the Bioenergy Association of New Zealand, the use of bioenergy nationwide has been steadily growing over the past 20 years, particularly for commercial and industrial heating.
However, the cost of installing biomass boilers remains a barrier for many companies looking to make the switch.
“We explored geothermal and electric heating, but biomass made the most long-term sense,” says Pierre.
“Even though it was a multi-million-dollar project, the payback was greater.”
Support from Energy Efficiency and Conservation Authority (EECA) helped reduce overall capital costs by around one third, making the transition to biomass heating more financially viable.
“We live in an area with an abundant supply of wood waste that we can make use of,” Pierre says.
“It just makes sense to turn that local resource into clean, usable energy.”
Standing inside the 1,400m², 12.5-metre-high boiler shed, it is packed with burners, pipes, a heat transfer station, and a maze of controls - it’s clear this project has been a major opportunity.
It’s given everyone involved hands-on experience and valuable expertise in biomass systems - knowledge and skills that will only grow more important as the region moves towards cleaner, renewable energy sources.
