EnergyAustralia has been granted regulatory approval to divert the Morwell River away from the Yallourn brown coal mine into the Latrobe River, so it can attempt to fix the flood-damaged embankment, the company has announced.
It comes as the nearby 1,480 megawatt Yallourn Power Station returns to near three quarter capacity, after a period of operating just one of its four units in an effort to conserve coal.
Victoria’s Environmental Protection Authority granted the fast-tracked approval to divert the river after the Victorian Government declared an “energy emergency” just under two weeks ago, after extreme weather on June 9 and 10.
That weather event, which also tore through Dandenong Ranges, blowing down trees and causing prolonged power outages, dumped huge volumes of rain in the Latrobe River catchment, swelling the Morwell River to nearly 40 times its usual volume.
The excess flow weakened the Morwell diversion wall, causing cracks to appear in it. EnergyAustralia was concerned the embankment had been perilously weakened and could burst, flooding the Yallourn coal mine. The mine feeds Yallourn power plant, a 1,480 megawatt generator which provides 20 per cent of Victoria’s electricity.
Under the EPA’s ruling, EnergyAustralia will now be allowed to discharge 232 megalitres per day into the Latrobe River, to be diverted from the Township Field pond.
EnergyAustralia energy executive Liz Westcott said the ruling would allow a temporary diversion of water away from the mine, but added the long term plan would be to permanently divert most of the river flow into the Latrobe River via two pieplines.
“This emergency discharge is expected to have a minor impact on the Latrobe River as it is a temporary measure,” she said.
“Our long-term strategy is to minimise any impact by transferring the majority of natural Morwell River flows along two pipelines directly to the Latrobe River, bypassing the area at risk.”
She said diverting the river was “essential to complete the damage assessment alongside critical, permanent repairs to be undertaken”. The company said initial repair work to the cracks in the Morwell diversion wall would be completed this week, though a more a thorough assessment of structural damage will be carried out once the river is diverted.
“There are additional diversion options that need to be progressed. Once they are finalised, similar with today we will inform the community so they’re clear on our approach and have confidence we are caring for the surrounding environment,” Westcott said.
The Yallourn Power Station had been operating just one of its four units for since the extreme weather, as it had been forced to suspend mining in much of the neighbouring coal mine, and was at risk of running out of coal.
However, mining during the day resumed on Friday 25 June, and allowed EnergyAustralia to fire up another two units.
Environmental groups had been concerned that EnergyAustralia would attempt to divert the water into either the disused western part of the Yallourn mine, or the abandoned Hazelwood pit. There were concerns both pits contain toxic coal ash, and filling them with water would pollute ground water.
Diverting the water into the Latrobe River was the preferred option, because the Morwell River already flows into the Latrobe River further downstream.
James Fernyhough is a reporter at RenewEconomy. He has worked at The Australian Financial Review and the Financial Times, and is interested in all things related to climate change and the transition to a low-carbon economy.