Rob R. wrote:I looked up wholesale propane prices a few weeks ago...$1.40/gal or a little less.
If you are paying $300/ton for coal and $1.85/gal. for propane, and your coal stove, furnace, or boiler is 60% efficient (real world), and your ultra modern condensing propane furnace or boiler is 94% efficient, the breakdown is as follows for one million "realized" BTU's:
13,350 BTU's per pound x 0.60 = 8,010 realized BTU's per pound
1,000,000 BTU/ 8,010 BTU/lb. = 125 lbs.
$300/ton / 2,000 lbs./ton = $0.15 per pound
125 lbs. x $0.15/lb. = $18.75 per million BTU's
91,600 BTU's per gallon x 0.94 = 86,100 BTU's per gallon realized
1,000,000 BTU / 86,100 BTU/gal. = 11.614 gal.
$1.85/gal. x 11.614 gal = $21.49 per million BTU's
At $1.61/gal. propane and anthracite are equivalent in cost to the end user, provided that the end user has a condensing propane furnace or boiler rated at 94% efficiency, and the end user is paying $300 per ton for anthracite, and is seeing 60% overall system efficiency. The gap is narrowing for those of us who do not live in coal country and must therefore pay high prices for anthracite coal.
The more I go over the numbers, the more convinced I become that my real world BTU yield (overall system yield) from coal is 8,000 BTU's per pound. Prior to actually using it, I had been assuming that I would get 10,000 BTU's per pound.