G.—ENGINEERING 153 
expended on the plant is, one quarter 43 per cent. debentures, one quarter 
54 per cent. preference shares, and one half ordinary shares expected to 
pay 7 per cent., or 6 per cent. all over. Depreciation and reserve are 
34 per cent. The cost per kw. of the normal station is £14 per kw., 
and of the pit-head station £15. Coal is 13s. per ton at 11,500 B.Th.U., 
and waste coal is 5s. at 10,000 B.Th.U. Salaries, wages, repairs, main- 
tenance, and stores are the same for both, and are at the average rates for 
this size of station. All charges for rates and taxes, office expenses, and 
other general expenses are omitted. 
The curves are shown in Fig. 1. At all load factors the reduction in 
cost at the pit-head station is about one-twentieth of a penny per unit. 
While this reduction does not look impressive when compared to the 
usual charges for lighting, it makes a substantial difference to the cost of 
the unit for domestic heating, which is now down to 0-5 pence in some 
places ; and it will be shown that any lowering of cost of production is 
followed by a decrease in cost of distribution, so that there will be a 
beneficial improvement on the first economy. 
[More recent figures of steam station costs show reductions in wages 
and repairs amounting to some o-or pence per unit, varying very little 
with the load factor. This correction lowers the curves for both normal 
and pit-head stations equally, so the saving due to the pit-head station 
_ is not altered.] 
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WATER POWER. 
In England there is at present no question of electric supply of any 
magnitude from water power. The Severn scheme is receding into the 
background, as the cost of generation from coal goes steadily down. 
When the Association met in Edinburgh in 1921, this Section devoted 
some attention to water power, and no one ventured to prophesy so great 
a change in every item in the cost of production from coal as has actually 
taken place. 
The chief part of the cost of water power lies in the civil engineering work, 
for the water turbines, now reduced in cost and improved in efficiency, 
are financially an unimportant part. There is a dead weight of capital 
expended on permanent works, and their very permanence is against 
them. Repayment charges may be put low, but they remain while the 
rival steam stations are installing cheaper, larger, and more efficient 
machines, and reducing fuel, wages, and capital charges. In Scotland 
these years have seen the planning of several ambitious schemes, some of 
which have been undertaken and are nearing completion. As engineering 
work they are well conceived and in every way excellent, but already their 
expected production costs are being hard pressed by their rivals, and the 
end is not yet. This paper shows that substantial reductions are quite 
feasible, in addition to the gradual reductions that have gone on steadily 
and show no signs of ceasing. In the Highlands and everywhere north 
of the industrial belt from Glasgow to Fife, excepting the large towns on 
the east coast, the hydro-electric station is in a strong position, for its 
foot is on its native heath. But in the Lowlands and in coast towns 
obtaining sea-borne coal, in the author’s opinion it is fighting a losing 
battle. 
The cost of a hydro-electric scheme cannot be given a single figure 
