A LARGE-scale commercial tomato glasshouse facility in New South Wales has embraced liquid natural gas (LNG) as a means of providing a constant growing temperature.
Glasshouses and major protected cropping facilities have traditionally relied on liquefied petroleum gas (LPG) or diesel for heating, however the Costa Group's Guyra plant has gone with LNG for its seedling production.
The switchover came in consultation with gas providers BOC and Elgas.
As one Australia's largest vegetable producers, the Costa Croup supplies to major supermarkets, independent grocers and a range of food industry stakeholders, which demand consistent quality and delivery.
Located on the Northern Tablelands in one of Australia's highest towns, Guyra is known for its cold winters. Its summer temperature rarely exceeds 30 degrees centigrade.
It is here the Costa Group has established its 20 hectare glasshouse which produces 11 million kilograms of truss tomatoes each year.
The decision to go with LNG was based on several key "fits" to the company's outlook.
Australia has an abundance of natural gas, with BOC operating a number of LNG plants in Queensland, Victoria and Tasmania.
It also has a dedicated delivery fleet of tankers to supply businesses across Australia.
According to BOC, unlike the price of diesel and LPG which are linked to overseas indices, the price of LNG is much more stable, which allows for more control in business budgeting.
The Costa Group planned to construct an additional 10ha glasshouse at the site to grow a further 450,000 plants.
To achieve optimum harvest levels, the climate in the glasshouse was required to remain within a temperature range of 16 to 28°C all year round and be kept rich in Carbon Dioxide (CO2).
After extensive research and planning, the company settled on LNG as the best fuel for the situation.
The Guyra facility has no piped gas supply, yet the greenhouse requires heating all year round with thousands of plants representing millions of dollars of investment.
BOC and Elgas delivered and installed an 18m tall vessel that connected to the facility’s water heater and provided CO2 to the glasshouses.
The LNG fuel helps heat around five megalitres of water that runs through more than 60km of heating pipes.
Costa’s glasshouse manager at Guyra Paul Andersen said LNG was an unknown for the company's operations but it had given some great results.
A strict planting schedule placed heavy expectations on the gas project's delivery.
“Some 50 days before we plant them out in the glasshouse,” Mr Andersen said.
“We have to propagate those plants. There’s a significant cost in getting those plants into that glasshouse. Once the decision to propagate has been made, we simply have to meet the deadlines on the project.”
The weather itself threw up additional challenges during the six-week installation in the middle of winter.
On the system’s first day of operation, temperatures dropped to minus five degrees.
“We had snow that week, some very cold conditions,” Mr Andersen said.
“We had the gas boiler operating up to its maximum limit because we were on a deadline for planting; everything had to be working properly during the commissioning process.
“And it did. There were quite a few extremely happy people jumping up and down at the successful outcome.”
One the key themes to the Costa Group's operations is a focus on sustainable and environmentally-responsible farming practices such as efficient water management and the use of natural predators where possible to control pests.
In keeping with this, the company wanted to use a fuel source that was cleaner than the fossil fuel alternatives.
It also wanted a fuel source that would provide clean CO2.
During the growing hours of the tomato plant, feeding CO2 into the glasshouse speeds up the photosynthesis process meaning each plant grows quicker and bears more fruit.
LNG is considered an environmentally cleaner fuel than many alternatives and the CO2 emitted can be utilised by the plants.
“This works out very well as the flue emissions from the heating are actually pumped directly back into the glasshouse to the plants, which thrive on it,” Mr Andersen said.
The resulting increase in crop yield is significant.
“It’s difficult to correlate the direct benefit with so many other variables but it represents a very significant monetary amount every year,” he said.
LNG is harder to ignite than diesel and is less of a fire hazard than many commonly-used fuels. LNG is not held under pressure which greatly reduces the likelihood of explosions.
LNG is non-toxic and non-corrosive and will not pollute land or water resources in the event of a leak into the environment.
Nevertheless, glasshouse staff were given full safety training.
BOC and Elgas developed a way of utilising the chilling effect that is generated when the liquid LNG is turned into gas.
This will be used to cool the CO2 released into the glasshouses so that it stays in the "growing zone" of the plants for a longer period, optimising its effect.
During the first few weeks of operation, demand on supplies was particularly high.
BOC monitors the gas levels remotely 24 hours a day.
It even changed the scheduling of its delivery fleet to ensure the Tomato Exchange didn’t run out of gas.
Mr Andersen said the remote monitoring provided certainty on the heating aspect.
"We were told when we would need more fuel and when the trucks were going to arrive. We didn’t have to worry," he said.
"BOC and Elgas report on the amount of gas used and devise convenient delivery plans with the facility managers.
“It’s the ideal solution for us; it is working very well and is increasing the quantity and quality of the tomatoes we produce."