4 seconds faster (within milliseconds of the frequency drop event occurring) than the coal plant contracted to provide frequency response services.
"But in reality, the response from the Tesla big battery was even quicker than that – in milliseconds – but too fast for the AEMO data to record.
Importantly, by the time that the contracted Gladstone coal unit had gotten out of bed and put its socks on so it can inject more into the grid – it is paid to respond in six seconds – the fall in frequency had already been arrested and was being reversed."
TL;DR The reserve system did this to show its skills. It can respond faster than any existing base load generators, and can derive revenue not only from providing energy on demand, but also grid services (in this case, frequency response).
When a contingency happens (loss of equipment such as a generator), units respond pretty much immediately due to governor response in the unit itself (good ole' inertia). Most RTO/ISOs in the USA (I know AEMO is in Australia) have a very large amount of power already ready to go if a unit trips offline. Using batteries to help with this is being worked on. They already exist, but new market rules are being drafted in order to allow them to be taken advantage of and properly compensated. The term is stored energy resource. Google that term in conjunction with ISO-NE, PJM, MISO, SPP, NYISO, CAISO...etc.
The requirements were relaxed because the intention was to have an entirely market-driven mechanism for frequency control. The system reliability impacts were an unintended consequence.
"But in reality, the response from the Tesla big battery was even quicker than that – in milliseconds – but too fast for the AEMO data to record.
Importantly, by the time that the contracted Gladstone coal unit had gotten out of bed and put its socks on so it can inject more into the grid – it is paid to respond in six seconds – the fall in frequency had already been arrested and was being reversed."
TL;DR The reserve system did this to show its skills. It can respond faster than any existing base load generators, and can derive revenue not only from providing energy on demand, but also grid services (in this case, frequency response).
Tesla plans to provide these services in a virtual fashion with vehicles in the future: https://i.imgur.com/oLBNeW4.png