The final report of Tasmanian Energy Security Taskforce (set up in the wake of Basslink breakdown) has been released.Climate Tasmania is generally pleased with the findings, in particular that it acknowledges and summarises the actual negative impact that climate change is imposing on the state’s hydro-electric system – an issue that has had little public exposure to date.
Below is the extract describing the issue of declining runoff from the Taskforce’s summary report.
The Climate Tasmania group has on several occasions raised this climate-related trend in our submissions.
Owing to a lag time between observed weather and observed long-term trends we believe that this points to a significant protracted factor that sensibly needs to be fed into future energy planning over time.
Prudence on this matter is further reinforced by the Coorperative Research Centre‘s findings to the effect that Tasmania’s western river systems are forecasted to receive less inflows in the coming century as our weather systems adjust to climate change.
Essentially this prediction, plus the confirmation of this trend to date, means that that Tasmania’s electricity supply shortfall over time is highly likely to increase further unless additional non-hydro generation is added to make up for this added decline in hydro-electric generation capacity over time.
Impact of climate change
Tasmania has experienced a downward trend in total annual rainfall and runoff since 1970, with the largest changes being observed in autumn concurrent with these decreases, a significant reduction in inflows to hydro-electric catchments has been observed in Tasmania since the mid-1970s, with an acceleration of the trend since the mid-1990s
Climate change is projected to decrease inflows in the central plateau catchments, which may have a significant impact on power generation as these feed into the major storage of Great Lake. Projected changes to the seasonality of inflows in the western catchments may also reduce power generation
These changes have implications for Hydro Tasmania’s long-term average yield assumptions and management of water storages over the next 10-20 years, particularly Great Lake and Lake Gordon/ Pedder.
Seasonal and inter-annual rainfall variability will continue to pose the largest hydrological risks over the short to medium term, rather than long-term climate change impacts
Other climate change projections relevant to energy security include decreased summer and autumn wind speeds that may reduce wind generation capacity (and coincide with projected declines in inflows during these months), and an increase in extreme events that may affect electricity infrastructure (e.g. bushfires, intense rainfall events and flooding)
The Taskforce’s final report and summary reports can be viewed here.
Climate Tasmania’s submission to this process can be viewed here.