Figure 1 



ENERGY DOLLARS 



refrigeration: 1% 



ventilation: 5-10% 



soil sterilization: 7-9% 



office & warehouse lighting: 2% 



Typical Annual Energy Dollars Spent in a Commercial Greenhouse Operation 



■' Variations are dependent upon climate, greenhouse design, structural conditions, and crops grown. 



Figure 2 



FUEL COST COMPARI SON 



60 70 SO 90 ICO no 120 130 140 160 



Coal, $/ton I 1 1 1 1 1 1 1 1 ' 



Natural Gas, $/therm 



Fuel Oil, $/gallon 



Propane, $/gallon 



Green Wood Chips, 30 

 45% moisture, $/ton >— 



.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 



0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 



0.50 0.60 0.70 



0.90 1.00 



40 50 60 70 80 



Heating Equivalent Cost, Dollars per Million Btu's ($/MBtu) 



Assumptions 



Coal: 13,000 Btu/lb. 60% efficiency. $/MBtu = $/ton ^ 13.8 



Natural Gas: Therm = 100,000 Btu. 70% efficiency. $/MBtu = $therm ~ 14.3 



Fuel Oil (Average #2 & #6): 145,000 Btu/gallon. 70% efficiency. $/MBtu = $/gallon x 9.8 



Propane: 85,000 Btu/gal. 70% efficiency. $/MBtu = $/gallon x 16.8 



Wood Chips: 45% moisture. 38oo Btu/lb, 75% efficiency. $/MBtu = $/ton ^ 5.7 



December/January 15 



