Hydro lakes below normal

Press, 17 June 1988, Page 42

Hydro lakes below normal

By NIGEL MALTHUS A generally dry autumn has allowed South Island hydro lakes to fall to lower than normal levels for this time of year. At 55 per cent of nominal full, South Island hydro capacity was 560 gigawatt-hours below normal, said Mr Graham Hodge, Electricorp’s South Island regional commercial manager. At 46 per cent of nominal full, North Island hydro lakes were, however, higher than normal, to make a total shortfall for New Zealand of 440 GWh. The shortfall was “not serious at all,” but showed that this was a dry year. It represented little more than a sixtieth of New Zealand’s total annual electricity consumption. Storage levels had been improving over the last few weeks, Mr Hodge said. Electricorp had not yet declared any “notifiable days” for any areas of the South Island. “Notifiable days” will arise when Electricorp expects cold weather to boost demand, and will ask supply authorities in the affected areas to shed demand where possible. They will be informed a

day ahead. The idea is to limit peak demand nationally so that as much electricity as possible is generated by cheap hydro dams, and as little as possible by expensive methods such as oil and coal firing. Mr Hodge said that the notifiable days system was experimental but ought to provide cost savings which could be handed on to supply authorities and consumers. It was introduced as part of the complex new pricing structure introduced by Electricorp this year. Similar systems have been used for years at the retail level, 'where authorities such as the Christchurch Municipal Electricity Department allow certain industrial customers a cheaper tariff on the basis that consumption will have to be curtailed at peak demand periods. The M.E.D. which has been told to expect between six and 12 notifiable days in June, July and August, held a seminar recently to explain to some of its major customers how they will be involved in working to the Electricorp “notifiable days” system.