Todays “Australian” has an article by Guy Barnett, Minister for Primary Industries and Water in the Tasmanian parliament titled “Tasmania the “battery” to power the mainland”.
In the late 80s I did time in Queenstown – (still not sure what I did to deserve it) – so I have an appreciation of the Hydro resources in Tasmania. Mr Barnett says that with a bit of jiggling and another Bass-link cable the apple isle will keep our lights on and we can get rid of coal and feel really good.
It is true that Tasmania has some very good hydro resources which were developed in the time when each state took responsibility for its own power supply and competed for industry with other states. The Bell Bay smelter which is about to close was established because of the cheap power the Tasmanian hydro system could produce, even though the construction of schemes got out of control and nearly bankrupted the state.
These hydro schemes are not immediately suitable for storage. They have machinery that only generates and does not pump and in most cases the water used simply flows away down the river. This is not to say that some could not be converted but the costs would be significant as would be the time scale and the green backlash when plans were made to build “lower storage” dams downstream – think of the Gordon below Franklin fiasco of the 80s. It is also worth remembering that Bass-link has failed before, putting Tasmania in it up to the neck and negating any transfer to “the mainland”.
There seems to be a fantasyland idea that we have “excess renewable energy” sitting around just waiting to be “stored” for a windless day of sunless night. All we have to do is spend heaps and everything will be fine. In reality, electricity is an instantaneous “commodity”. Generation must meet demand second by second, which is why the “renewables” are so useless. There is no “excess electricity” in the system, only “excess generating capacity” which will be underutilised in the event that the renewables can muster more than the demand at the particular moment.
Also, Mr Barnett seems unfamiliar with the difference between power and energy. The article mentions that “AEMO forecasts the nation needs 17 gigawatts of storage by 2040 to stabilise energy production”. We consume gigawatt hours so the storage requirement has a time dimension. The typical “big batteries” that are being approved here in SA have a capacity of about 100 megawatt hours or 0.1 gigawatt hours.
Whether the storage is by pumped hydro or batteries there is a loss incurred where only about 80% of the energy used to “charge it up” is recovered for use, so they are energy users not energy producers.
At present the grid has a minimum demand of around 17 GW and a maximum somewhere between 28 and 32 GW depending on the time of year. If we used our existing resources of coal, gas and hydro intelligently this demand could be met at all times and the supply would be reliable.
Some time ago I posted an article titled “Where were the renewables when we needed them” which analysed the two days of highest consumption in 2018. On the 18 January 2018 wind and solar provided 2% of the total consumption, the rest was from coal, (76%), gas, (12%) and Hydro (10%).
On that day the “non-renewables” provided 580,000 MWh out of a total for the day of 596,000. To replace that with “storage” using 100 MWh batteries needs 5,960 batteries at about $100 million each. The next day was about the same so there would be no “excess” to re-charge the batteries, and so it goes – an exercise in tail chasing. Using “pumped hydro” has the same disadvantages where the capacity needed for storage and the excess generating capacity to keep it charged becomes a self-defeating proposition.
I do not see that Tasmania will keep the nations lights on anytime soon and wonder why we keep on with national self-harm for nothing.