Outside, it’s the dead of winter in the Niagara region of southern Ontario. As the temperature hovers around -5° C, a whipping wind makes it feel much colder. But inside the sprawling Rosa Flora complex, 40 acres of flowers bloom, undisturbed by the chill outside
It takes a lot of energy to generate the necessary heat to grow flowers year-round, and Rosa Flora accomplishes this with the aid of its own combined heat and power (CHP) system that has earned recognition from the Canadian government for innovation and efficiency. Established in 1978 by Dutch immigrants, Otto and Corrine Bulk, Rosa Flora Limited has become one of the largest wholesale distributor of gerbera (daisies) in North America, with 1.5 million square feet of greenhouse space. Since energy represents roughly 40 percent of costs for the typical greenhouse operation, efforts to reduce energy consumption and production costs are always top of mind. The couple brought with them renewable energy concepts learned in the Netherlands that were put into practice early on in establishing the commercial greenhouse operation in Dunnville, Ontario.
Customer Profile
Location: Dunnville, ON
Application: Greenhouse
Equpiment: G3250C and G3516
Rosa Flora Power Profile
Investment in Energy
Throughout its 36-year history, the company has expanded the use of alternative and renewable energy sources, while introducing other technologies and energy efficiency initiatives, including extensive use of double-pane acrylic glass in Rosa Flora’s greenhouses, which saves $1 million per year. The greenhouse structures also include a state-of-the-art design approach to minimize energy use. Lighting is carefully considered given that some crops require long hours under light, especially in the fall and winter months. The company uses automatic control systems that turn the lights on or off depending on the amount of natural light coming into the facility.
In 2003, Rosa Flora added a biomass heating system run by three combustors. The boilers use chips ground from recyclable wood to heat hot water, providing 15,000 kW of heat, which is circulated throughout the greenhouses. This offsets the use of fossil fuels, ensures the quality and consistency of fuel and reduces costs. Additionally, the hot water pipes run from the boilers through underground tunnels that stretch across the facility to transfer any lost heat to the greenhouse floor. The company also installed a wind turbine in 2006 to produce 600 kW of power, reducing reliance on the grid. While an expensive investment, the wind turbine provides 5 to 10 percent of Rosa Flora’s electricity requirements. The company’s efforts to conserve energy have attracted national attention. In 2006, Rosa Flora was recognized by the Canadian Industry Program for Energy Conservation (CIPEC) as an Industrial Energy Innovator. This program helps companies create a stronger economy and reduce greenhouse gas emissions through energy efficiency. As Rosa Flora expanded its operations to include combined heat and power (CHP), executives looked for a cutting-edge system that would further reduce total energy costs and help make their operations even more self-sufficient. “One of the drivers for investing in CHP is the continuing rise of power prices here in Ontario,” said Ralph DeBoer, operations manager at Rosa Flora. “With the stability we hope to see in natural gas pricing, CHP can become more attractive to growers who use heat and electricity.”
Dating back to its first installation 22 years ago, the Cat 3516s have accumulated 82,000 and 65,000 hours respectively, and continue to run well, DeBoer says. After more than 20 years of operation, the G3516s recently had an in-frame overhaul, where many of the moving components and wear items were replaced.
Routine maintenance of the generators is handled by Rosa Flora, while Toromont Power Systems technicians perform scheduled maintenance on both a quarterly and annual basis.
“As part of those greenhouse expansion plans, I would love to see combined heat and power be included,” DeBoer says. “It’s a great and efficient way to accomplish both electrical and thermal demand for us as greenhouse growers and we would love to see Caterpillar and Toromont be part of any future expansion of our CHP system.”
G3512 Natural Gas Generator for Greenhouse
“Truly, one of the strengths of the relationship between Rosa Flora and Toromont is the responsive service,” DeBoer says. “It’s come when we call—that’s the agreement that we have with them. We have maintenance technicians from Toromont who literally live around the corner and are dedicated to making sure that Rosa Flora’s generators are up and running.”
In addition to the Cat-powered CHP system, Rosa Flora delivers flowers throughout the Northeast via its own fleet of trucks, which are powered by Cat engines. The grower has further plans to expand within the next two to five years.
We are operating over 90% efficiency
A Leader in CHP
Rosa Flora partnered with Toromont Power Systems in 1992 to develop a customized CHP system with the ability to provide electricity for electrical loads and thermal energy for warming the greenhouse when natural light isn’t enough. “I think we are unique in that we started with CHP 22 years ago, so we are familiar with the technology and what needs to happen to make it work,” says operations manager Ralph DeBoer, a partner in the business and son-in-law of the founders. “To realize some of the economies of scale with CHP, you do need to be a certain size, and we certainly qualify for that.”.
Rosa Flora installed the two G3516 generators in 1992. Each produces 800 kW of electrical energy, and 1 MW of useable thermal energy. The net result is a system that is around 80 percent efficient in converting natural gas energy into useable heat and power, a much higher number than can be achieved via separate electricity and boiler utilities.
“Those engines are still running today, and the kilowatts that we make are used to offset the cost of electricity that we would normally purchase from our electric utility, the Ontario Power Authority,” DeBoer says.
In early 2011, the grower commissioned two G3520Cs, which each produce 2 MW of electricity and deliver approximately 3 MW of thermal energy to support greenhouse heating needs. Together the four generators supply a total of 5.6 MW of power.
“The real advantage for us as greenhouse growers with CHP equipment is during the coldest months of the year, when the heat is worth the most to us,” DeBoer says. “We will generally run the generators from mid-August to mid-April. We do have a thermal load in the summer, as well, to de-humidify the greenhouse.”
The heat from the generators is recovered through jacket water, exhaust, lube oil, and after-cooler recovery. The captured heat is used to send hot water directly into the greenhouse and heat it. If the heat is not used immediately, it is stored in insulated hot water storage tanks, which act as a thermal battery for use in the evening. If the heat is not used immediately, it is stored in insulated hot water storage tanks, which act as a thermal battery for use in the evening.
Rosa Flora purchased two additional G3520C generators from Toromont Power Systems in 2014, which is part of another 4 MW CHP plant. The new CHP plant supports a contractual arrangement with the Ontario Power Authority, where Rosa Flora sells the electricity it generates back to the grid and use the heat from the generator to warm its greenhouses.
“As a fresh cut flower grower here in Ontario, one of the drivers to investing in CHP is that over the last few years, the power prices from the grid have continued to rise,” DeBoer says. “With the stability that we hope to see in natural gas pricing, CHP can become more and more attractive to us as a grower that uses heat and electricity, and purchases natural gas.”
Given the exacting conditions required to grow fresh cut flowers, the proper combination of heat, light and moisture must be present at all times. “CHP ensures that our greenhouses stay warm,” DeBoer says. “It’s one more tool that we have when it’s 20 below and the wind is blowing at 50 mph—we have combined heat and power units that we can fire up to heat the greenhouses. In addition to biomass and natural gas boilers, it’s one more added level of security.” Additionally, in the event of a power outage on the main grid, the CHP system can be used as standby power until utility power is restored.
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