Nebraska Greenhouse Operator Evaluates the Feasibility of Biomass Heating

In Firth, NE, Stacy Adams operates a family greenhouse business as a second income. 

Adams is a professional horticulturist, raised in construction. For many years Adams has been a building manager and actively involved with renovation of greenhouse structures and mechanical repairs at his place of employment.

Not long ago, Adams was at the mercy of his local COOP regarding the propane they were purchasing for his greenhouse business. Adams needed to identify a suitable alternative energy source to heat their greenhouse, using a more affordable or less volatile priced fuel.  

In 2006, Adams submitted a proposal to the North Central Region Sustainable Agriculture Research and Education (NCR-SARE) Farmer Rancher Grant program, and received a grant for $5,560. The purpose of this project was to evaluate the feasibility of using a biomass heating unit for greenhouses. Of particular interest was, whether the biomass unit heater will be able to recover quickly enough for the unique demands within the greenhouse.

“My goal was to find a flexible fueled furnace, affordable to a smaller grower, various fuels that allowed me expense flexibility and yet, one that could meet the demands of a greenhouse operation. Much data was generated during the SARE project, which gave the engineers much delight,” said Adams. “As a grower, I saw some interesting results which other growers may find of value and some results which environmentally conscious consumers may want to learn.

”Expense, durability and fuel flexibility were Adams’ primary considerations when selecting which biomass heating unit to test. Given its fuel flexibility and the apparent durability for harsh environments, Adams visited with Eagle Manufacturing Incorporated about using their shop model 200 for the study. In discussions with Joe Engle, owner, on his concerns of temperature stability within the greenhouse, they decided to error on the side of caution and use the model 300. 

With biomass heating, one would expect an increase in labor due to fuel handling and unit cleaning. In an effort to reduce handling labor, Adams chose to purchase a used 235 bushel bulk bin from a local farming operation that no longer was feeding hogs.

The greenhouse was heated during the growing season utilizing corn as the primary energy source. The previous propane unit heater was utilized as back-up heating in the event of temperature problems. Careful records were maintained to record time of labor and production issues. Labor time was recorded in minutes utilizing $10.00 per hour as the pay rate. University of Nebraska researchers installed monitoring equipment to evaluate the temperature stability within the greenhouse and to track changes in humidity and free water on the glazing or leaf surfaces.

The low fire condition of the furnace was of concern to the grower as a waste of fuel, but this was quickly discounted given the benefits of maintaining the continued burn. With the continual burning of the furnace, tests conducted showed a significant reduction in the humidity within the greenhouse.

Several nut shells were tested and were found to be suitable for use within the biomass furnace. 

“With the high energy content within the shells, if the nuts are processed appropriately and are available, this would be the best energy producing biomass for heat generation,” explained Adams.

Adams says his project has given him the encouragement he needed to become more aggressive in sustainable production of plants. 

“My project may help other growers look at their heating alternatives and perhaps find a way to support their neighboring farmers, reduce our dependence on fossil fuels and through the use of by-product fuel options, stretch the capability of each crop grown and reduce our waste,” said Adams.

Since 1988, the Sustainable Agriculture Research and Education (SARE) program has helped advance farming systems that are profitable, environmentally sound and good for communities through a nationwide research and education grants program. The program, part of USDA’s Cooperative State Research, Education, and Extension Service, funds projects and conducts outreach designed to improve agricultural systems.

Want more information? See the related SARE grant(s) FNC06-629, The Suitability of Flexible Fuel Biomass Heating for the Greenhouse Crop Environment and the Effect of Crop Profitability When Compared to Propane Heating.