Economics of electric transmission and feeder systems for urban electrical supply

One of the most important subjects before the electric supply industry at the present time is that of distribution of current, and by distribution in this instance I mean the conveyance of current from the point or points of generation to the places at which it is to be utilised. The science of generation has been studied and improved tremendously during the last few years, in fact, steady progress has been made in Power Station machinery and methods ever since the commencement of the commercial production of electricity as regards both continuity of service as well as economy of production. Many engineers living to-day have been actively engaged in the industry from its earliest days, and have followed the progress made from the time when rough measurements were first made of the quantity of coal used to produce a kilowatt hour, being then from 5 lbs. to 10 lbs., till the present time, when we closely determine the British Thermal Units needed per unit and have already reached such a figure on an average not more than one-fifth of what prevailed 25 years ago. I say already, because further almost revolutionary improvements in the process of converting the potential heat in fuel to electricity are being tried out or proposed, and the next generation is likely to see present average figures cut in half at least, for these new methods include the pulverizing of fuel, the use of steam pressures of 1,200 lbs. per square inch, the employment of mercury vapour as the working fluid, and the very latest referred to by Mr. Otley in his recent address to the South African Intitution of Engineers, a complete reconsideration of the means of converting water into steam by substituting superheaters for the ordinary boilers. The result of some or all of these methods in combination gives us grounds for hope that in the not very distant future a kilowatt hour will be generated at an expenditure of not more than 10,000 or 12,000 B.T.U.s, and the significance of this outlook is that the commercial applications of electricity will be vastly extended and, in fact, light, heat and power will be exclusively obtained through the medium of the passage of an electric current, for if we can send out a kilowatt for an hour at the expenditure of no more than a pound of coal nothing else except water power will be able to compete as a prime mover, and even water power will be in the field only in those cases where it is fairly easy of development and where expensive dams and long pipe lines and transmission lines are not required. We may be in the way to see another swing of the pendulum, and those countries with plentiful deposits of cheap coal in reasonable proximity to condensing water may come into the picture again as cheap electricity producers for electro-chemical and steel making industries.