It'd need the output limited, which is doable, but fundamentally well the solar farm connects to the same substation, via feeder, that the gas turbines are located at. Physically the solar farm's about 2km away.
So in theory at least, nothing precludes running the gas turbine to provide the 50Hz then just operating the solar and battery so long as there remains some load on the gas turbine at all times.
Doing that would really just be a small version of what's being done at a state level in SA routinely, bearing in mind we do at times only have two conventional synchronous machines (gas turbine or steam) running in the whole system and the rest done with solar and wind.
There might be some issues with inertia and so on, but so long as protection works, I'll argue that an insecure system with a risk of customers ending up in the dark if something trips is far better than having customers actually in the dark. Those with a legal mindset won't agree however - rules are rules no matter what.
In the article
I orignally highlighted from Renew Economy
The AGL website
boasts that the Broken Hill battery can – with the grid-forming inverters funded by the Australian Renewable Energy Agency – “support the reliable supply of electricity to Broken Hill in the event of line failure and provide efficient grid support for the region.”
Clearly, it didn’t do that when the line failed in the storm and it now emerges (thanks to the sharp eyes of a Renew Economy reader) that its ability to create mini grid in such circumstances had been deliberately disabled.
An AGL report into the battery’s system strength capabilities, published under the Knowledge Sharing requirements of ARENA funding, reveals that Transgrid had required the battery to include an “anti-islanding” scheme, meaning that its ability to provide the islanding service had been deliberately inhibited.
“It had been hoped that the Broken Hill Battery could be used to supply the Broken Hill load in the event of supply from the grid not being available due to faults or maintenance outages,”
the report says.
“This service had previously been provided by Essential Energy using two 25MW GTs (gas turbines) running on diesel.
“When Essential Energy decided that it no longer wished to provide this service, AGL offered to configure the battery to operate in island mode in conjunction with the Broken Hill solar farm, Silverton wind farm and the existing GTs which they had an option to purchase.
So the project was orignally planned to operate in island mode just for the very contingency that we recently arrived at- no power conng from the external grid.
“Transgrid ran a RIT-T process to select its preferred provider of standby supply for Broken Hill and chose a compressed air storage alternative. As a consequence, and to avoid adverse interaction between the battery and the compressed air system, the battery has been configured under Transgrid guidance to include an anti-islanding scheme.
“The battery provider is still contracted to include islanding functionality, but this functionality will be inhibited to avoid interaction with the compressed air scheme.”
Transgrdi is partly owned by spark Infrastructure, an Astralian investment fund with 15%, and Utilities trust of Australia, another Australian Invesment trust.
However, the majority is foreign owned.
OMERS, a Canadian Pension Fund, which has 20% , CDPQ another Candian investment fund which has 22.5% ,and the Abudhabi based Tawreed Investments has a further 20%.
The above is important when one looks at the next steps.
The compressed air storage project that AGL is referring to
is the 200 MW, 1600 MWh facility planned by Canada’s Hydrostor at the site of a cavern in one of the underground silver mines that has made the region famous.
So it just so happens that a solution for preferred standby was was awarded to a Candian firm.
But that project – which
has also won an underwriting agreement from the NSW government in a long duration storage tender – will not be built for several years, with a target date of 2027 at the earlier.
So a majority foreign owned entity decided that another foreign owned entity would supply the long duration storage, and was underwritten for funding by the NSW government.
And it is not clear why Transgrid required AGL to disable the “islanding” capabilities of the battery, particularly given the ageing nature of the diesel generators that are to be replaced, one of which is completely out of action, and the other only able to operate at just over half of its capacity due to various limitations.
The AGL report appears to make clear that the battery would have been able to support the huge wind farm and large solar farm that are located near Broken Hill, and allow them to generate and provide power to the locals, including the mines that have been forced to down tools.
I am surprised that the Minns government has not bought all this out into the open, as the original sale process and lease to transgrd was all done under the then Baird led coalition government.
Mick