110 



Indiana University Studies 



Fixed charges — 



Interest at 5 per cent 



Depreciation at 8 per cent 



Insurance and taxes at 2 per cent 



$4,605.00 

 7,368.00 

 1,842.00 



Total 



$13,815.00 



Operating cost — 



Coal, 1,500 tons at $1.55 per ton. . . . 



Labor 



Repairs 



Oil, waste, etc., including incidentals 



$2,325.00 

 3,100.00 



920.00 

 1,000.00 



Total 



$7,345.00 



Total yearly power and operating cost 



$21,160.00 



Figuring as before on a 75 per cent load for 10 hours per day 

 for 300 days in the year, the cost of power would be .94 cents. 

 Or if the running time were reduced to 200 days, the cost of power 

 would be about li cents per horse-power per hour. 



These figures show that in installations of this size the cost 

 of power is in favor of the gas producer, and as the size of the 

 units increases the difference becomes constantly greater in favor 

 of the gas equipment. Up to this point the value of the by- 

 products from the coal formed in the manufacture of producer 

 gas is hardly great enough to warrant the installation of the ex- 

 pensive machinery necessary for their recovery, but as soon as the 

 size of the plant passes beyond this point, recovery of by-products 

 can be carried on economically. 



The power problem in the quarry district is a larger one than 

 the simple matter of installing better small plants and handling 

 them more carefully, altho, as will be seen by the figures already 

 quoted, quite a portion of the present waste could be eliminated 

 even in this way. The greatest saving in the cost of power 

 would result from the production of the power in large central 

 plants and its distribution to the quarries and mills of the district 

 by electrical transmission. The large plant when properly con- 

 structed and handled is always a more economical source of power 

 than even the best handled small plant. The stone belt of South- 

 ern Indiana is a reasonably compact district, and the problem of a 

 large central plant is therefore a simple one. 



In the treatment of the development of power in central 

 plants three types of plants present themselves for considera- 



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