Drummondville, QC: A greenhouse producing tomatoes for the Quebec market turned out to be the ideal host for a new 8 MW cogeneration project fueled by gas from a landfill site. The project features a large hot water storage tank and the ability to burn surplus landfill gas if necessary to supplement the heat supplied to the greenhouses by the power project.
When Jacques Demers, owner of Demers Greenhouses, learned that Waste Management was building an 8 MW landfill gas fuelled power plant near Drummondville, QC, he quickly realized this was an excellent opportunity to take advantage of heat recovered from the power plant. After exploring the possibilities with Waste Management, Demers decided to invest in the heat recovery equipment and other infrastructure required to capture and utilize the heat from the power plant. No government assistance was involved.
Mr. Demers contracted with European Power Systems Ltd. to implement the project in August of 2011. By the end of 2012 the system had provided almost 7000 MWh of energy to the new greenhouse.
During the first phase of the project, heat is being recovered from the engine jacket water and oil cooler circuits only. This is sufficient to heat the 3.2 hectare (8 acre) greenhouse built by Demers in the first phase. The system is designed such that exhaust heat recovery equipment can easily be added at a later date, to supply additional heat for a planned second phase greenhouse expansion sometime in the future.
Five large heat exchangers recover heat from the 5 gas engines in the form of hot water at a temperature of about 95°C. A piping system with approximately 1.8 km of pre-insulated pipes commonly used in district energy systems, supplied by Urecon, transfers the hot water from the power plant to the greenhouse. At the greenhouse the hot water interfaces with the greenhouse boiler plant. When heat is not required in the greenhouse, it is stored within a large, 2,000,000 liter hot water storage tank for use at some later time.
In the event more heat is required than what is provided from the CHP plant, a boiler at the greenhouse can operate with landfill gas to provide the additional heat required. The water is returned to the CHP plant at a temperature in the range of 40°C to 70°C. In the event the greenhouse cannot use all the heat provided by the power plant, special temperature control mixing valves will modulate to allow engine cooling water to flow to large radiators, which provide the necessary cooling for the various engine cooling circuits.