GAS SUPPLY

Nelson Evening Mail, Volume 80, 7 April 1945, Page 4

GAS SUPPLY

DEMAND INCREASING 94 MILLION”CUBIC FEET USED LAST YEAR NELSON PLANT AT FULL PRESSURE Despite the greatly increased Use °f electricity in Nelson in recent years, especially since the opening °f the CObb hydro-electric scheme, the demand for gas has continued to gr»w steadily since 1934 and last year the output of the Nelson gasworks was nearly 4,000,000 cubic fe e t above the 1943 peak, the total amount produced being just uhder 94,000,000 cubic feet. With the replacement of worn equipment seriously Interfered with by war conditions and high-grade co a | difficult to secure, this factor has allowed the wdrks no safety margin and almost any emergency is liable to seriously affect the city supply.

The immediate cause of the recent period of rationing—which is still being continued during the evenings—was the breaking of a heavy chain on the re-tort-charging machine. This chain was known to be badly worn and was one item of a quantity of equipment ordered from England three years ago and which has still not arrived. This meant that the stoking of the retorts had to be carried out by hand, a difficult and slow operation. In the short period before the machine was repaired, all reserves of gas were used and with the poor grade of coal then available it was impossible to make good the loss without imposing a somewhat drastic plan of rationing. The retort-charging machine was net the only section of the wbrks which was in bad repair, however, and unless a very serious shortage during the winter was to be risked, one of the three beds of six retorts had to be demolished and rebuilt. This was decided on and the work is at present in progress. The bed was badly worn and cracked and the gas produced was dilutfli with flue gasses so that its calorific power dropped to such an extent thst the six retorts made only a small contribution to the output of the works. The number of retorts in this bed is to be increased from six to eight when it is rebuilt and it is expected that the work will be completed within six weeks. Two further retorts will then be added to one of the existing beds and it is considered that the gasworks will be able to meet the normal winter demands by the end of June. During the summer the demand drops by about one-third and it is intended to rebuild a second set of retorts next year during the light-load period.

The chief reason for the relaxation of gas rationing in recent weeks has been ,the improved quality of the coal made available to the works through the co-operation of the Mines Department. The coal previously used, which came from Westport, was producing between 12,000 and 13,000 cubic feet of gas per ton. whereas the highest grade coal would produce approximately 16,000 cubic feet. The coal which has now been supplied is a mixture from three State mi rites—Rewanui, Dunnollie, and Liverpool—and it is giving 14,000 cubic feet per ton. At the present lime, as a result of the rationing, improved coal and the recent spell of warm weather, a good reserve of gas has been built up, but with a cold snap or almost any breakdown at the works the position would quickly deteriorate and it has therefore been decided to continue rationing during the evenings until the work on the retorts is completed.