Canadian Biomass Magazine

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Going green: Greenhouse sees benefits switching to a wood chip boiler for heating


November 17, 2021
By Guillaume Roy, Translated by Peter Diekmeyer

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Frédéric Tremblay installed a Hargassner wood chip boiler at his vegetable farm and greenhouse, Jardins d’Elisabeth, in Saint-Elzéar, Que. Photos courtesy Jardins d’Elisabeth.

In April 2020, when Frédéric Tremblay installed a Hargassner wood chip boiler at Jardins d’Elisabeth, the vegetable farm and greenhouse he co-owns in Saint-Elzéar, Que., his primary focus was on efficiency, effectiveness, and productivity.

Tremblay also has his own forestry operations, “So, it makes sense to put leftover wood to good use,” he says. 

Getting the wood ready to burn takes a lot of work. But, Tremblay regards the investment in the Hargassner boiler as more than worth it, as it costs next him next to nothing in raw material costs to heat his greenhouses all year round.

Tremblay started by using a standard grinder. But, the system was inadequate and got jammed from time to time. 

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“The key is using the right material with the right boiler,” he says. That problem was solved after he bought a German-made Heizohack wood chipper from Heizomat to transform his logs into wood chips optimized for use in the boiler. Since then, the boiler has worked like a charm.

“Effective processing and drying of the wood are also important,” Tremblay says. 

“You have to let lumber and logs dry for at least a year, if not two,” he continues. “It’s also important to make sure that air can pass through the wood piles.”

Tremblay’s nearly $130,000 investment to acquire the boiler and the chipper will be financed in part by a grant from the Transition Énergie Québec (TEQ) program. The size of the grant will vary depending on operational performance. According to an initial TAQ assessment, Tremblay will be eligible to receive the lower amount of either 75 per cent of his eligible costs, $125 per ton to compensate for the greenhouse gas emissions the boiler and chipper will enable him to cut, or an amount that will enable him to payback his initial investment over three years. 

“Whatever the calculation, I will be able to repay my investment in three years,” Tremblay says. 

In contrast, using propane to heat his greenhouse operations so he could grow produce during the fall would have cost close to $15,000 per year. However, the calculation may seem biased because a producer will not heat his or her greenhouse if it cannot generate enough yield, and thereby sufficient income, to offset heating costs. 

That was the case with Tremblay, who estimates that the high propane costs would have made greenhouse operations during the fall season uneconomical. 

Instead, the biomass boiler enables him to change his business model by producing more, without needing to burn fossil fuels.

With ample timber supply on his land, getting the biomass costs him nothing except time. But, Tremblay believes that the project would still be economical even if he had to buy the wood. 

“I had a truckload of birch delivered into my yard last year for $1,800. Going forward, I expect to consume the equivalent of two truckloads annually,” he explains. “That adds up to about $3,500, which is far less than propane would cost.”

The greenhouses must also be heated in the summer and fall to enable dehumidification, as excess humidity can cause disease problems in the plants. 

“I’d be really upset if I had to burn propane to dehumidify,” says Tremblay.

In addition to extending his growing season in the fall, the boiler also enables Tremblay to heat the greenhouse in the winter to about five degrees Celsius, in part so he can start operations faster in the spring, because the heated ground does not need to be thawed. For now, Tremblay only produces some green vegetables, like spinach. However, he is looking at doing more in the future. 

Why import petroleum products when an alternate energy resource is within reach? For Frédéric Tremblay, biomass is the ideal heating fuel option. •

Inside Jardins d’Elisabeth, which produces some green vegetables like spinach.

Hargassner boiler improvemens

  • Patented zinc rotary valve, which increases the reliability of the feed auger supply. 
  • Monitoring of engine power and automatic reverse functions to facilitate deblocking. 
  • Combustion quality control with the Lambda sensor and the air combustion control devices.
  • Improvement of the automatic cleaning and descending system. 
  • Recycling a portion of the combustion fumes to cool the combustion chamber and the ashes.