Lots to talk about here, but hard to say just how many people would be excited about the frequency of the grid in Australia…. So we will keep it (a little) under control.
The Tesla big battery is having a big impact on Australia’s electricity market, far beyond the South Australia grid where it was expected to time shift a small amount of wind energy and provide network services and emergency back-up in case of a major problem.
Last Thursday, one of the biggest coal units in Australia, Loy Yang A 3, tripped without warning at 1.59am, with the sudden loss of 560MW and causing a slump in frequency on the network.
What happened next has stunned electricity industry insiders and given food for thought over the near to medium term future of the grid, such was the rapid response of the Tesla big battery to an event that happened nearly 1,000km away.
Even before the Loy Yang A unit had finished tripping, the 100MW/129MWh had responded, injecting 7.3MW into the network to help arrest a slump in frequency that had fallen below 49.80Hertz.
A few things here, firstly, the author does not seem to fully understand (or they write in such a way that I am confused about their understanding) the point of mains frequency and automation.
I was involved in a customer application for Opto in measuring mains frequency.
You can read my blog about it over on the Opto 22 blog.
Unlike in that blog where I glossed over the why and focused on the how, here I want to mention the why… The customer was UK based and they wanted to be able to start a series of backup generators (diesel and petrol (and perhaps natural gas)) if the mains frequency sagged.
Its important to note that the frequency will sag before the voltage if there is too much load and not enough generation… So, in short, the Opto measures the grid, if it sags, start the generator and get paid. And yes, do this optomagicly and do it in under 200 milliseconds.
Tesla is no different.
The inverters measure the grid frequency, if it sags, start the export inverters, and no doubt they can do it much faster than 200 milliseconds.
Here is the thing. Why in the UK, why Australia, why not USA? Same answer.
Because the UK is small, the USA grid is fully interconnected (except for Texas) and too big, Australia is small.
In other words, the USA grid frequency is solid because from coast to coast it is connected and there are lots of places that will spin up a generator and prop things up if it sags. In the UK and Australia, no so much. Thus small petrol or battery generators can make a difference.
Our customer was selling the Opt bolt on option to his customers and they got paid every time they started their generators and saved the day, just like Teslas big battery did (will).
You can stop reading there if you like… But I wanted to explain why I wonder about the author of this piece….
So why did the Tesla big battery respond when not contracted?
One reason is because it can, and so it did.
The other reason is less clear, but more intriguing. It is contracted to provide such grid services by the South Australia government.
The details of that contract are not released, but it wouldn’t surprise if that contract allowed, or even encouraged, such intervention – just to rub in the message about a cleaner, faster, smarter grid to the technology dinosaurs in the eastern states.
They seem to make the point that somehow Tesla could chose to see that the grid frequency instability was from Victoria and not South Australia and thus not respond, because ‘it is not in our contract to prop up Victoria’.
Australia does not have a smart grid, one spot on the grid can not know where the electrons are coming from. That is not how it works.
Tesla saw the sag and had to do something about it to protect itself.
I love electronics because of this reason, cold, mechanical, emotionless, without politics or borders……