^9— POWER GENERATION AND DISTRIBUTION. 

 By R. A. Dawbarn, M.I.C.E., M.I.E.E. 



Just 600 years ago the British Parliament successfully petitioned 

 the King to prohibit the use of coal in London, from which time its 

 consumption gradually increased, but it is only within the lives of 

 living men that the great demand for it has arisen for the generation 

 of mechanical power, with which we are for the moment more directly 

 concerned. 



It is almost startling to recall the fact that only 70 years have 

 elapsed since mail coaching was at its height — a zenith represented by 

 54 coaches throughout England, together unable to carry as many 

 passengers as a single railway train to-day. 



But it is perhaps still more remarkable that 20 years from the 

 height of its prosperity sufficed to entirely supersede the mail coach * 

 and to establish the age of mechanical fower. 



Closely following the spread of railways came that rapid 

 development of trade, demanding the use of power for almost every 

 manufacturing industry, and with this demand a corresponding 

 increase in the consumption of coal, until, at the present time, 

 its output in England is fully 7 tons per annum per head of 

 population. 



But the consumption of coal in the Transvaal — chiefly for the 

 generation of power — already exceeds 10 tons per head of white 

 population, and anything which affects economy of fuel cannot fail 

 to be of importance to South Africa. 



Although the demands for power have been increasing with mar- 

 vellous rapidity for half a century, singularly little advance has been 

 made since the days of Watt in reducing the consumption of coal 

 per unit of mechanical energy obtained from it, in spite of the 

 realization of the fact that manufacturing countries must inevitably 

 lose some all-important industries so soon as the cost of coal is 

 seriously increased by the necessity for obtaining it from greater 

 depths. 



It is both diflScult and expensive to provide means for accurately 

 recording the average power consumed in factories in which many 

 power-using tools are intermittently employed, except where electric 

 motors are in use when accurate records of the energy absorbed — 

 however intermittent the load — can be obtained automatically, by the 

 use of meters. It is therefore only since the establishment of electric 

 distribution of energy that accurate costs of generating and 

 distributing power have been systematically recorded. 



On setting to work the earlier electric power stations, it was a 

 surprise to most engineers to find how large the consumption of fuel 

 was per unit delivered to the consumer. Consumptions of coal as 

 high as 15 lbs. and more per unit sold, with non-condensing engines, 

 were not uncommon, whilst 12 lbs. per unit sold was frequently 

 experienced with condensing engines. 



Note. — The first mail coach ran in 1784. The height of coaching was 

 reached in 1838. The last mail coach from London ceased running in 

 1856. 



