ALCOHOL 



39 



Gas engines operating on natural gas 

 or on illuminating gas from city mains 

 will, on fluctuation of load with the reg- 

 ular work, average about 12,000 heat units 

 per brake horsepower hour, or 20 per cent 

 thermal efficiency. Exploding engines 

 operating on crude oil will average about 

 2.5,000 heat units per brake horsepower 

 hour, which is equivalent to about 10 per 

 cent thermal efficiency. Exploding en- 

 gines using gasoline should operate at a 

 thermal efficiency of about 19 per cent un- 

 der similar operating conditions. 



The efficiency of an alcohol engine may 

 be assumed at this time to be unknown, 

 but as alcohol can be burned in engines 

 designed for gasoline, it may be assumed 

 that such an engine will have with alcohol 

 fuel the same thermal efficiency as with 

 gasoline, to-wit, 19 per cent for fair work- 

 ing conditions. 



From the above brief discussion of the 

 efficiency of different methods of power 

 generation from different fuels it appears 

 that quite a range is possible, though not 



so great a range as exists in the case of 

 cost of fuel energy. Efficiency is seen to 

 lie somewhere between 2^i; and 20 per cent 

 for all the fuels under working conditions. 

 It is known that actual thermal efficiency 

 under bad conditions may be less than one 

 per cent and under the best conditions 

 as high as 40 per cent, but these are rare 

 and unusual cases. The range given is 

 sufficient to indicate that a highly effi- 

 cient method may make the fuel cost per 

 unit of power less with quite expensive 

 fuel than it would be with cheaper fuel 

 used in a less efficient machine. It is 

 also perfectly clear that without proper 

 information on the efficiency of the ma- 

 chine or the efficiency of the plant it is 

 impossible to tell what the cost of fuel 

 per horsepower hour will be, even though 

 the price of the fuel per ton or per gal- 

 lon be known. From the figures given on 

 the cost of fuel and a fair average for 

 plant efficiency the cost of fuel per horse- 

 power hour is computed as given in the 

 following tables: 



Cost of Energy in Fuels 



Kind of Fuel 



Cost of Fuel 



British thermal units 

 (B. T. U.) 



Number of 



B. T. U. 



bought 



for SI 



Small .anthracite . 

 Large anthracite. 

 Illuminating gas. 



Natural gas 



Crude oil 



Kerosene 



do 



Gasoline 



do 



Grain alcohol . . . . 



do 



$2.50 per ton 



6.25 per ton 



1.00 per 1.000 cubic feet. 



.10 per 1.000 cubic feet. 



.04 per gallon 



.10 per gallon 



.30 per gallon 



.10 per gallon 



.30 per gallon 



.30 per gallon 



.40 per gallon 



12,500 

 14,000 

 5.50 

 1,000 

 20,000 

 20,000 

 20,000 

 20,000 

 20,000 

 12,000 

 12,000 



per pound .... 

 per pound .... 

 per cubic foot, 

 per cubic foot. 

 per pound. . . . 

 per pound .... 

 per pound. . . . 

 per pound. . . . 

 per pound .... 

 per pound ... . 

 per pound .... 



10,000,000 



4,500,000 



550,000 



10,000,000 



3,650,000 



1,200.000 



400,000 



1,200,000 



400,000 



270,000 



200.000 



Fuel Cost of Power 



a Efficiency of alcohol is assumed to be the same as 

 tioDS of use. 



that of gasoline for identical condl- 



