Wednesday, 6 April 2011

Power-cost surge fear

Hobart Mercury
29 March 2011, Page: 5

TASMANIA will be without one of its major power stations this winter, increasing the likelihood of more imports than usual over Basslink to make up for any shortfall. Hydro Tasmania plans to close the Poatina power station for up to five months from April 1 while it paints the inside of the pipeline, which runs down the face of the Western Tiers from Great Lake to the power station. The refurbishment project has a budget of about $15 million and will employ up to 30 workers.

When Tasmanians wind up their heaters to full, peak winter consumption can be up to to 1900 MWs a day compared with the average demand over the year of 1300. Spot prices on the National Electricity Market Management Company can vary widely, as they did in May 2006 when Hydro was forced to pay $10,000 a MW when the electricity system crashed. This compares with the usual price of $30 to $70 a MW.

In preparation for the shutdown, Hydro Tasmania has been running the Poatina power station at higher than usual generation loads for the past 12 months and preserving water in Lake Gordon. Great Lake is 31% full compared with 47.4% in Lake Gordon. The Gordon power station has the capacity to generate 432 MWs compared with the 342 MWs at Poatina. The refurbishment work had originally been planned to be completed last summer but was postponed until after the farm irrigation season in the Cressy Longford area However, delaying the paintwork until the cooler months could mean that paint in the pipe takes longer to dry.

A spokeswoman said the problem was being addressed by heating the pipeline to reduce the drying time. "Recent inspections have revealed that most of the original anti corrosion paintwork inside the 46 year old [pipeline] is in poor condition", she said. The project also aims to reduce the friction in the pipeline to allow it to generate more electricity. Using a low friction paint, the water will travel quicker and turn turbines faster. Great Lake holds about 45% of the state's energy storage capacity and the Poatina station produces about 12% of the state's energy output.