Using Biomass to Supplement Natural Gas for Hydronic Heating in a Greenhouse Complex

Chad Wheeley, Mary Emplaincourt, and B.K. Hodge, Mississippi State University

Keywords

Abstract

In 2003, the Industrial Assessment Center at Mississippi State University performed an energy assessment for Natchez Trace Greenhouses. A recommendation made to the facility to reduce natural gas usage was to replace the existing natural gas boilers with bio-mass boilers that burn biomass fuels for use in a hydronic heating system.
    Burning wood shavings and/or other bio-mass fuels was recommended as a viable fuel alternative to offset the rising price of natural gas. Wood chips with an average energy cost of $1.64/MMBtu (from 2004-2007) are readily available from a local sawmill. Grain corn with an energy cost of $5.81.MMBtu in 2003/2004 can be purchased locally. In 2003/2004, the facility was paying $5.78/MMBtu for natural gas and anticipated a significant increase in the price of natural gas.
    Partial implementation in 2004–2005 and rapidly escalating natural gas prices convinced the owner to supplement natural gas with wood shavings and corn to heat the greenhouses. Three new 40-hp fire-tube boilers were installed and existing 40-hp natural gas boiler was converted to burn biomass fuels. Based on the assessment, the facility was able to obtain loans from the State of Mississippi and the U. S. Department of Agriculture to implement the recommendation.
    During the winter of 2005–2006, the new fire-tube and the retrofitted boilers using biomass fuels were fully operational. Planer wood shavings, corn, and wood pellets are the fuels being considered for burning. Future fuel possibilities are briquettes made of cottonseed hulls. The proposed paper will analyze the fuel savings realized by the facility, the cost of implementation, the savings, the added maintenance and operating costs, and the effects of using biomass as fuel.