Hydro Tasmania has started its annual cloud seeding season except over West Coast areas as weak hydrology continues to affect reservoir storage and hydroelectric generation.
The cloud seeding programme started at the beginning of the month over Tasmania and will look to take opportunities over the Great Lake, Lake Gordon, the Mersey-Forth and the Upper and Lower Derwent storages.
However, the delay in completion of an independent study of the impact of cloud seeding on the West Coast has left out the King and Pieman catchments. In the absence of the report, community concerns in the West Coast over the impact of cloud seeding led to the catchments being left out of the current work.
The ongoing drought in Tasmania has resulted in energy yield from hydro catchments being down to only 18% of normal average for the last five months, which is less than the previous record low of 26%.
Overall, the power utility’s storages are just over 18% full. The rainfall that did come was preserved to some degree due to power market replacement by the Basslink interconnector to mainland Australia and also from gas-fired generation. Locally, though, a few run-of-river stations benefited from up to 80mm of rainfall recently in the west and north of the island.
Net imports of electricity via Basslink this financial year have been the equivalent of approximately 11% of reservoir storage. The utility has imported 1,732GWh and exported 215GWh.
The cloud seeding season continues to November. Hydro Tasmania hopes the talks with West Coast communities will enable their catchments to be included for the next cloud seeding season, in 2009.