Hydro lake levels rising steadily

The level of Lake Hawea was yesterday at 68% of its storage capacity for electricity generation and rising.

The level of Lake Hawea is steadily rising back above normal as steady rain and a decrease in power consumption has led to a capacity glut on Contact Energy's Clutha River hydro-electricity scheme.

The lake's level yesterday sat at 343.72m above sea level - the equivalent of 68% full in terms of generation.

The lake has risen from a July level of 338.14m asl - 14cm above Lake Hawea's statutory emergency minimum level, or 2% full in terms of generation.

Contact Energy spokesman Jonathan Hill said the company was releasing minimum flows from Lake Hawea's control structure, in line with resource consent conditions.

Lake Wanaka, which also feeds Contact's Clutha scheme, was yesterday at 277.89m asl and rising steadily.

Contact has been spilling water, primarily from the Roxburgh dam but also from the Clyde dam.

Mr Hill said the water spillage was due to a breakdown at the Tiwai Point aluminium smelter at Bluff, which had reduced electricity consumption in the lower South Island.

Contact was unable to "physically export" power from its Clutha River hydro scheme into the national transmission grid.