Comparing the Environmental and Economic Impacts of Propane and Gasoline Fueled Mowers.

The rising cost of gasoline and widespread concern over global warming has resulted in a major demand for alternative fuels.  Propane is a fuel source that has the potential to be used as an alternative to gasoline; however, little is known regarding the use of propane powered mowers in the turf industry.  A two year study was initiated at the University of Tennessee (Knoxville, TN) in 2008 to evaluate the environmental and economic impacts of maintaining turf with propane and gasoline fueled mowers.  The study was arranged as a completely randomized design with three replications.  A single lawn care company was provided with a gasoline and propane fuel powered mower in 2008 and 2009.  The oil of each mower was analyzed for Iron, Chromium, Nickel, Aluminum, Copper, Lead, Tin, Cadmium and Silver after every 50 hours of use for replication.  Following the analysis oil was removed from the engine of each mower and replaced.   Emissions tests for each mower were performed three times during the mowing season with each test being a replicate.  Emissions tested were hydrocarbons, nitrogen oxides, carbon dioxide, oxygen and carbon monoxide.  Fuel consumption data was taken weekly and used to generate cost analysis data for each mower.  While significant differences between mowers were detected in both the emissions and oil data, relationships were not consistent across replicates.  In 2008 the average fuel consumption for the propane mower was higher (1.45 gallons per hour) than what was measured for the gasoline mower (1.23 gallons per hour) in 2008.  The cost of operating a propane mower was lower than the cost of operating a gasoline mower in 2008.  While data suggests an economic benefit of operating a propane mower, additional oil and emissions data is needed to evaluate potential environmental impacts.