One cool cycle

The GE-Jenbacher JMS 620 gas engine provides electricity to the local municipality to offset heating costs for the greenhouse

Imagine the gas bill for a 65-acre greenhouse that grows tomatoes year-round in frigid Canada. And you thought your heating bill was high!

For Great Northern Hydroponics (GNH), in Kingsville, Ontario, however, heating costs aren’t as painful as they might be, thanks to the natural gas cogeneration plant next door that not only supplies the heat needed to grow millions of tomatoes; it also provides carbon dioxide to grow the fruit faster and larger. In turn, a symbiotic relationship is created with the greenhouse to cool the power plant. To offset the heating costs, GNH sells the electrical power that is created back to the local municipality.

Saving money — and the environment
The benefit of the cogeneration facility is to provide “cost-efficient heat and CO₂ available for growing operations in the adjacent greenhouses,” says Guido van het Hof, president and general manager of Soave Agricultural Group (SAG). “The electricity sales to the grid help offset our energy bill.”

And how. GNH, which is an entity of SAG, expects to offset their energy costs by at least 40 percent with the energy they can put back into the grid. The energy they sell back to the power company will provide light and power to 12,000 to 15,000 homes in the Kingsville area.

The project has its roots in a 2007 request from the Ontario Power Authority (OPA) for green energy projects. GNH, located 25 miles southwest of Windsor, was one of seven successful qualifiers that year for an environmentally friendly project like this one. Soon, GNH set its sights on the greenhouse industry in Europe, which had been using cogeneration and CO₂ fertilization systems for over a decade.

The result was a 20-year commitment with the Canadian government to purchase the power that is generated from the plant to power thousands of residential homes in the local area. In turn, GNH is capturing tons of CO₂ — about 15,000 tons annually, which would normally go into the atmosphere — and using it to help produce the more than three million cases of tomatoes they grow each year in their greenhouse.

Also enabling year-round production of tomatoes is the fact that 15 of the greenhouse’s 65 acres are lit with high-intensity grow lights. GNH produces more than 26 million pounds of fresh gourmet tomatoes, 75 percent of which are sold to U.S. markets, including several restaurants and other outlets in and around metro Detroit. The rest are sent down to Florida and as far west as Texas. GNH relies on Mastronardi Produce to help market their Sunset brand of tomatoes.

Talking the technology
The GNH greenhouse and cogeneration plant is the first of its kind in North America. It’s actually a tri-generation facility, meaning it burns natural gas to generate heat, electricity and CO₂, creating a “useful power cycle,” according to a statement from GNH. The greenhouse serves the purpose of providing a cooling unit for the power plant located next door by drawing heat to use in the greenhouse. The thermal energy from the power plant engines is stored in hot water tanks and can heat the greenhouse as needed.

The acoustical enclosure of the JE-Jenbacher JMS 620 gas engine includes a FlueGas scrubbing unit to clean food-grade CO2

So how does all this work? The 12 mega-watt system features four GE-Jenbacher JMS 620 gas engines as well as heat recovery and exhaust treatment equipment, noise abatement and systems controls. Via the burning of natural gas, the plant produces heat and power, providing electrical generation, hot water and carbon dioxide to the huge greenhouse. As a result, “substantial” amounts of thermal energy and CO₂ are created, according to van het Hof. The thermal energy — hot water, actually — is then supplied to the greenhouse for tomato production.

Rather than pump more carbon dioxide into the atmosphere, the system can capture CO₂ and use it in tomato production by using the latest in environmental technology to clean the exhaust emissions, thus extracting the CO₂ for use in the greenhouse. The cogeneration plant is entirely computerized, requiring only one or two maintenance personnel to troubleshoot and provide routine maintenance to the system.

The lifespan of a greenhouse tomato is intentionally short; there are only seven weeks from flowering to picking, according to van het Hof. The CO₂ from the cogeneration plant helps speed up production of the tomatoes, as well as make them grow larger. The tomatoes also reach the desired level of sugars quicker with this growing method. This makes the whole cogeneration project even more efficient and cost effective, he explains.

Other innovative growing practices at GNH include extensive use of biological controls, as well as raised troughs, run-off fertilizer recycling, and computerized louvers and climate controls, all which increase the nutritional value of the tomatoes, van het Hof says. These controls also help prevent fungal diseases from forming. van het Hof says the company toyed with the idea of using the cogeneration plant for energy to cool the greenhouse, but they found it isn’t cost effective in their climate.

GNH and Soave Agricultural Group became the first vegetable producer in Canada to meet the requirements of the Safe Quality Food (SQF) 1000 code, level 3 for Comprehensive Food Safety and Quality Management System. SQF is recognized by the Global Food Safety initiative.

Soave Enterprises, led by CEO Anthony Soave, is involved in a number of business enterprises — from agriculture to metals to automobiles. The enterprise even owns a cab company. Great Northern Hydroponics, established in 1998, is one of three entities of Soave Agricultural Group. The other two are Great Northern Seedlings and Soave Hydroponics Company.

Neil Moran is a horticulturist and regular contributor to Produce Grower. Visit his website at www.neilmoran.com.