After writing previous post, I wondered how much impact the Tesla battery of the Hornsdale Power Reserve actually has on the South Australia grid. Just looking at the numbers (the battery has a capacity of 100 MW and can deliver 129 MWh), I expected it to be rather insignificant. In the meanwhile, I came across a heated discussion on a reblog of previous post on the blog “Utopia, you are standing in it!“. That post was about the Tesla battery of the Hornsdale Power Reserve in South Australia. The discussion started with the comment that South Australia is a net exporter and after the question how long the Tesla battery would last, this suprising claim was made:
Long enough to stop potential blackouts in Melbourne because of the unreliability of their coal fired power stations! […]
Later in the discussion on the South Australia import/export balance, the claim was repeated in similar a wording:
[…] Thus the telsa battery can help Melbourne obviate blackouts caused by units in coal fired power plants breaking down regularly. […]
It is remarkable that such a small capacity could stop potential blackouts in a large city. If the capacity of the coal plants in Australia is in the same range as those in Europe, then the Tesla battery with a capacity of 100 MW / 129 MWh would fall woefully short in the event one such a plant would actually break down.
I was going to look into the impact of the Hornsdale battery anyway, so I thought it might be a good idea to start from this particular claim and see how the Hornsdale battery was able to prevent blackouts in Melbourne. That is one way to figure out what the impact of the battery is in practice.
Looking for more information on the South Australia grid, I encountered the first problem for the claim. Just take a look at the fuel mix of South Australia:
There is no coal in the energy mix of South Australia!
The Wiki page “List of power stations in South Australia” confirmed that there are no coal fired power power plants anymore in South Australia. The last one closed in May 2016.
That made me wonder how on earth the Tesla battery could help prevent blackouts in Melbourne due to regularly breaking down coal fired power plants, when there is no coal fired power plant left in South Australia to break down?
The solution presented itself when I encountered the second problem for that claim. When I was looking for more information on Melbourne, I found that Melbourne is a city in Victoria, not in South Australia!
Chances are very slim that this battery would help to prevent blackouts in Melbourne, roughly 1,000 km away from the Hornsdale Power Reserve.
But then, maybe Melbourne has its own “Tesla battery” that help to prevent blackouts caused by those regularly failing coal fired power plants? The Wiki page “List of power stations in Victoria (Australia)” did not state any grid-sized batteries in Victoria, but there was an entry in the EAMO dashboard for battery power (although it had zero output as far as I could go back).
I then found the article “Victoria to turn to Tesla battery power in time for next summer” in which was stated that a Tesla battery system would be build by the summer of the next year. The article is from March 2018, so that would make it operational in the summer of 2019.
The planned capacity is 55 MW and could deliver 80 MWh, roughy half the capacity of the Hornsdale Power Reserve. Expecting to save Melbourne with that capacity is I think wishful thinking. There are three coal fired power plants in Victoria: Loy Yang A (2,200 MW), Loy Yang B (1,500 MW) and Yalloum (1,480 MW). That tiny capacity of 55 MW will not be a match for even the smallest of the three.
According to the article, this 55 MW battery “will be big enough to power 20,000 households for one hour during peak demand periods” (most probably on condition that it is fully loaded at the moment of the coal fired power plant breakdown).
If we start from the assumption that the 80 MWh could provide electricity for 20,000 households at peak demand, then 1,480 MW could provide 370,000 households during one hour for the smallest coal fired power plant. In the further assumption that the battery would be able to provide enough power to those 370,000 households at any given moment, the power in the battery would last for 3 minutes and 14 seconds. Again, in the assumption that the battery was fully loaded at the start of the breakdown. If this battery serves the same purposes as the Hornsdale Power Reserve (frequency control and peak shaving), then this is very unlikely the case.
Okay, this is the worst case scenario when such a plant would fail at peak demand and its full capacity is relied upon. To his/her credit, the commenter later said:
[…] We simply do not have the renewable back up to compensate if the breakdowns are alrge as we saw two years ago. Telsa helps if the uit breakdown is ‘minor’
I think the first part is true. The second part is however puzzling. A power plant with a capacity of 1,480 to 2,200 MW breaking down is by no means a “minor” event and if a battery system with a capacity of 55 MW / 80 MWh (or even a 100 MW / 129 MWh in case of the Hornsdale Power Reserve) is able to compensate for such an event, then it most probably wasn’t a “break down” at all…