ELECTRIC POWER

Evening Post, Volume CXXXII, Issue 77, 27 September 1941, Page 11

ELECTRIC POWER

FUTURE PLANTS

BOTH STEAM AND HYDRO

ADVANCES IN DESIGN

In an address to power supply authority engineers, Mr. M. Cable, General Manager of the Electricity Department, Wellington, and president of the Power Engineers' Association for the past two years, laid before them facts and figures to support his statement that future power supply developments in New Zealand must include large and efficient steam plants as well as hydro plants. Mr. Cable went further, and said that within comparatively few years available water power in the North Island will be inadequate to meet the probable demand for power without assistance from steam generation.

When consideration was given to the remarkable growth of load throughout the Dominion in., the past 20 years, and bearing in mind that there was little evidence of any slackening in that growth, there appeared little prospect that the hydro extensions now in hand would be able to keep ahead and provide a margin to meet emergencies, said Mr. Cable.

Assuming that the power requirements of tlie Dominion due to the growth of industry necessitated a two to threefold increase in generating plant within the next 17 years--not unreasonable when it was remembered that Christchurch and Wellington had in 17 years increased their demands fivefold—it was evident that even if the whole of the undeveloped water power in the North Island was harnessed it would be inadequate to meet the demand without reliance on fuel plants, though the development of the extensive water power resources in the South Island should be ample for all power requirements for years to come. Hydro developments so far were those which could be most economically carried out and so had resulted in a supply of electricity at low rates, but future developments, particularly in the North Island, were likely to prove costly to the country.

COMPLEMENTARY PLANT

"In view of the large capital investment which will be absc-rbed in the development, of further water resources the claims of steam generation—not those based on standby plants operating in the Dominion, but on the results now being obtained by the highly efficient plants abroad, particularly in Britain and America —should receive the utmost consideration when further developments of our national electrical undertaking are under review," said Mr. Cable. "The time has undoubtedly arrived, in my opinion, when the installation of steam plant should be viewed as a complementary, j_.c not as a competitive, system to the existing hydro-electric development "

F* cm a recent review of power generating plants in the United States, said Mr. Cable, it was ascertained that in that country there were 114 hydro plants totalling 3,230,000 h.p., and 134 _,team plants with an aggregate capacity of 2,490,000 h.p., approximately 75 per cent, of the hydro capacity.

Much of the address ;was technical, in its . survey of the very great advances made in the efficiency and economy of steam plants, resulting from advances in design and the much higher steam pressures possible today, up to 20001b to the square inch, with still higher pressures in plants nowbuilding.

REVOLUTIONARY DESIGN.

The Velox boiler, one of the most revolutionary of designs, installed at the Evans Bay station, said Mr. Cable, had now been operating for four years, at full load for extended periods, with full satisfaction.

How revolutionary was the design of'the Velox boiler, he said, was conveyed in the description given by the editor of the engineering journal "Power." Velox bears about as much relation to the orthodox boiler as a duck-billed platypus bears to the household tabby cat. Features are 40 pounds furnace pressure, outside steam separator, and a gas turbine operated by flue gas. Here we have a boiler plant turned into a machine."

At the time the decision was made in favour of the Velox units, said Mr. Cable, no boilers of that type were installed in any part of the Empire, although a unit was operating at Haifa, Palestine, and the department had to rely on the results of its investiga^ tions, and reports of plants operating in Europe.