Higher costs are attributed to higher usage of fuel, labour, sophisticated technology and computers.Moreover, fuel cost increased by 44 percent between 1999 and 2000.
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Estimate Fuel Costs
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| Year |
1996
|
1997
|
1998
|
1999
|
2000
|
2009
|
| $ million |
$79
|
$97
|
$98
|
$110
|
$159
|
$303
|
You can make your own comparison of fuel costs using the following formulas. (This assumes heating unit efficiency of 80% for natural gas, propane, and fuel oil and 70% for cordwood, sawdust, and coal.)
- Natural gas $/MBtu = $/therm x 12.5
- Propane $/MBtu = $/gal x 13.5
- No.2 fuel oil $/MBtu = $/gal x 9.0
- No.4 fuel oil $/MBtu = $/gal x 8.6
- No.6 fuel oil $/MBtu = $/gal x 8.2
- Waste oil $/MBtu = $/gal x 10.7
- Cordwood, hardwood $/MBtu = $/cord x 0.07
- Cordwood, softwood $/MBtu = $/cord x 0.12
- Sawdust, green $/MBtu = $/ton x 0.16
- Anthracite coal $/MBtu = $/ton x 0.055
- Bituminous coal $/MBtu = $/ton x 0.06
USDA estimates show that a single greenhouse can produce more than 189 tons of CO2 per year.
The IRIS Solar System produces zero CO2 from fuel consumption and solar energy is always FREE.