M.E.D. loads

Press, 11 June 1982, Page 16

M.E.D. loads

Sir, — A recent M.E.D. advertisement said “you don’t have to worry” about your hot water heater. In fact it is a great worry to many householders during the winter that they will not have enough hot water for their minimum requirements. If the consumers were given more information they might cope better with the problem. I would like to know: (1) How can one tell if one’s water heater has been “rippled” off? It would then be possible to plan water use (inconvenient though it is to wash clothes and dishes at midnight), use other means e.g. heat water in the washing machine (expensive), use cold water soap (less effective). (2) How many hours a day may the water heaters be off? (3) Is the whole metropolitan area “rippled” at once, or is it done in areas, in fair rotation? (4) Why, is the “ripple” control used to turn off the water heaters on mild days and.at

week-ends, (when electricity demands of industry and commerce are reduced)? — Yours, etc.,

J. ROBERTSON.

May 27, 1982. [Mr J. H. Donald, general manager of the M.E.D. replies: "Reference to the department's advertisement indicates that your correspondent is aware of ‘Operation Peakload’ which is aimed at holding down costs to the consumer, and the department is appreciative of the encouraging response to this by electricity users. One way of reducing peaks is by control of domestic waterheaters which gives a net saving in annual bulk power charges to the M.E.D. of about $3.5 million per annum. This saving is passed on to consumers by way of electricity tariffs which are lower than would otherwise be possible. Replies to your correspondent's questions are as follows: (1.) There is no simple way by which a consumer can tell if the water heater has been “rippled" off. (2.) Last year, the -average water heating cut was approximately 2V t hours but the length of the cut will depend on the severity of the weather and the level of the resultant load. (3.) Only as much cutting as is necessary to control peaks is exercised and is carried out in fair rotation. Only on those days when very high peaks are likely would all consumers be “rippled off” at once. (4.) Ripple control signals are sent out every day and are used for such controlled services as street lighting, floodlighting, storage space heating and other purposes. It is possible that your correspondent has heard some of these signals and assumed that they are for waterheating control purposes. The department also sends out regular signals to operate water heater relays throughout the year to prevent them from becoming inoperative through lack of use, but on such occasions they are restored immediately afterwards. I would suggest that your correspondent discusses the problem with the department’s supply engineer or consumer advisory officer as there may be a simple solution.”]