G.— ENGINEERING. 169 



Power Company and the Aluminium Corporation in North Wales, it may 

 be taken that at least 400,000 kw. (continuous rating) could be developed 

 by inland water-power in Great Britain. 



Suggestions and schemes have also been put forward for the develop- 

 ment of tidal power, notably in the Severn Estuary ; and the Water Power 

 Resources Committee, after hearing evidence, reported that a prima facie 

 case had been made out, and that more detailed investigation should be 

 undertaken. A hydrographical survey is, in fact, now being conducted by 

 the Government. Preliminary estimates of the power available — -making 

 allowance for secondary water storage at high elevation working supple- 

 mentary turbines in order to level out the intermittency of the lunar 

 cycle — show that approximately 260,000 kw. could be generated, equivalent 

 to at least 1,000,000,000 units transmitted annually from this source. 

 It is possible that tidal schemes in other situations may hereafter be deemed 

 practicable ; but in no part of Great Britain can such potentialities be found 

 as in the Severn, not only because of the enormous volume of water 

 flowing and ebbing in that estuary, but also because the physical con- 

 figuration assists in producing a 47-foot rise at ordinary spring tides. 



The utilisation of water-power for electrical generation and transmission 

 is one of the finest and perhaps most fascinating ways of harnessing the 

 great forces in nature for the use and convenience of man. It is a power 

 which ought to be utilised as fully as possible in ouf country in the interests 

 of true national wealth. It must not be overlooked that a well-constructed 

 dam and works will last for centuries, that the wasting assets in the form 

 of turbines and possible pipe-lines represent only a small proportion of the 

 total expenditure. Moreover, of the total cost of electrical energy produced, 

 no less than 85 to 90 per cent, represents capital charges. When the capital 

 outlay on the permanent assets is redeemed the cost of energy is reduced 

 to a very low figure indeed. This is a factor which is insufficiently appre- 

 ciated in this country. Other countries which have been endowed with 

 more liberal sources of water-power will for this reason benefit considerably 

 a generation or two hence. 



This is an additional reason for so laying our plans in this industrial 

 country, where we must depend upon our industries — agricultural, 

 engineering, shipbuilding, textiles, and others — in order to live and continue 

 to exist as a great nation. It is essential that abundant power shall be 

 available in all necessary parts of the country. The bulk of this power, 

 as has been said, must be derived from coal. 



There is no known method of storing electricity on a very large scale, 

 and thus consideration must be given to the most economical means of 

 coping with the public demand from hour to hour, or even minute to minute. 

 If anyone will look at a 24-hour load-curve recorded at any electricity 

 station, a considerable variation in the height of the curve will be noted 

 at various times of the day or year according to the demand for power, 

 heating, traction, or lighting. But it will also be seen that if a line be 

 drawn through the curve parallel to the base, at a point some two-fifths 

 of the highest ordinate, all below that line represents an almost uniform 

 output all the year round, excepting week-ends and holidays ; in other 

 words, there is a base load of very high value, representing generally an 

 annual load factor of 50 or 60 per cent. The remainder of the curve, 



