476 Report S.A.A. Advancement of Science. 



It will be noticed that the advantages of increased load factor 

 are not so marked in the case of the private plant as with the public 

 supply undertaking. This is due to the latter requiring in any case 

 to employ staff for a 24 hours' service per day, whatever the load 

 factor may be, whereas the private plant requires only one shift, so 

 long as the running can be confined to ordinary factory hours. 



The advantages of gas plant compared with steam plant, 

 particularly for high load factors, are : — 



(i) The thermal efficiency is approximately twice as high 

 as in a steam plant, consequently only about half the 

 coal is consumed for a given duty. 



(2) The incidental and stand-by losses of a gas producer 

 plant are less than in a steam plant. 



(3) The water consumption of a gas engine and a pro- 

 ducer plant combined is far less than with steam 

 plant. 



(4) The repairs required by producers are less than the 

 repairs required by boilers. 



(5) The attendance required for a battery of producers is 

 less than for a battery of boilers doing the same duty 

 in H.P. hours. 



The disadvantages of producer gas plant are : — 



(i) That — omitting types designed solely for the use of 

 anthracite or coke — the capital outlay is somewhat 

 higher than for steam plant of similar capacity. 



(2) When constructed for the use of bitumenous coal they 

 occupy more space than steam plants. 



(3) They are not so well understood by the average 

 attendant as the steam engines and boilers. 



There is little doubt that with the increasing demand for large 

 gas engines and producers, their costs will in the near future be 

 materially reduced, whilst the one other disadvantage of importance, 

 namely, want of knowledge of gas plant on the part of attendants, 

 will quickly pass away with their increasing use. 



The losses through radiation and condensation of steam in long 

 ranges of steam pipes is sometimes enormous. There are factories 

 using a number of scattered steam engines consuming an average of 

 15 11 )s. of coal per B.H.P. hour, whereas there are no such losses 

 from gas mains. 



Just as it took ten years to establish the Parsons steam turbine, 

 so may several years elapse before the use of producer gas for the 

 development of power becomes general, but the author is convinced 

 thnt the vastly superior thermal efficiency of the gas engine compared 

 with the steam engine will certainly secure for it the most prominent 

 place in the second stage of the " Age of Mechanical Power " — the 

 stage of the Internal Combustion Engine. 



