Smurf, this links to a
live graphic of electricity supply & demand.
I found it interesting to see how strongly renewables contributed in South Australia.
The other interesting take was how State subsidies for solar have skewed PV output - NSW is a laggard.
AEMO puts out all the data in real time, the public website version is updated every 5 minutes, and there are a number of third party websites which present that raw data in an easier to understand form.
That's much the same as saying that the ASX provides data in real time which your broker's website or any other service you are using then presents in a more useful form via charts, scanning tools and so on. Same concept in that there's an "official" data source which others then do various things with.
What the electricity generating companies themselves do with it depends heavily on their own capabilities and strategy. It ranges from absolutely nothing, being purely a passive participant, to a fully fledged trading room with monitors everywhere displaying exactly what every plant, regardless of who owns it, is doing and which looks much like the sort of thing you'd see on financial news coverage in the background to some commentator speaking or footage of the trading floor at the New York Stock Exchange.
In terms of physical control, AEMO has two complete setups to run the National Electricity Market (Qld, NSW, ACT, Vic, Tas, SA). One's in Brisbane and the other is in Sydney and both are fully capable in the event that one were to be blown up by terrorists or whatever.
In addition to that Hydro Tasmania also has it's own fully fledged control room capable of running everything in Tasmania from the one place. Since Tas is part of the NEM that's effectively a backup to AEMO's systems but it's fully setup and could be considered as "plan C". For the record if the worst did happen then there are further options beyond that.
The other states don't have a single control room capable of running the whole show from one place but the power stations do have their own control rooms to run that power station and there are other places for controlling networks etc.
The one big word of caution I'll sound when looking at data is to realise that it is instantaneous unless stated otherwise. For example there's more than 2000 MW of gas-fired plant in Victoria literally none of which is running at the moment. Yes it can and does run but right now there's no need since demand is low, wind and solar are producing significant outputs, and with one exception all coal-fired plant is running flat out. So there's gas-fired plant which exists but if you look at anything displaying "live" production data you could well come away completely unaware of that.
The only other "catch" with data websites is that they don't distinguish when a fuel other than the main fuel is being used. Eg a lot of gas-fired plant fires oil as a backup fuel but they won't pick that up, since they just have power station x listed as "gas", and will thus show the source as "gas" even though oil is being fired in practice. That said, it's not common to fire oil in plant that mostly uses gas but it does happen from time to time - it was done in two generating units at one particular power station in SA last week for example.
Oil? Depending on the plant in question that's fuel oil (a thick black liquid), diesel, kerosene (jet aircraft fuel) or LPG ("BBQ gas") all of which are liquids partly (LPG) or entirely (the others) derived from crude oil. For convenience they're generally lumped together and referred to as either "liquid fuels" or simply "oil".
In terms of efficiency, that's a complex one. Coal plant efficiency doesn't vary hugely across the present fleet. The absolute worst is about two thirds as good as the absolute best so the variation isn't massive and the majority is in a narrower range in the middle. The difference isn't simply due to technology although that's a factor. The composition of the coal used is a major influence on the level of thermal efficiency which can be achieved and climate is also a factor.
For gas and oil fired plant however the differences are far greater with the worst gas-fired plant using more than twice as much gas, per unit of output, as the best and it's similar where liquid fuels are involved.
On a state by state basis over the past 12 months:
NSW:
Coal = 77.9%
Import from other states = 8.0%
Solar = 4.3% (3.0% houses etc, 1.3% large solar farms)
Wind = 4.2%
Hydro = 3.9%
Gas = 1.8%
Oil = minor
Export to other states = 0.4% of NSW supply
Qld:
Coal = 83.1%
Gas = 9.1%
Solar = 6.0% (of which houses etc 4.8%, large scale solar 1.2%)
Hydro = 1.2%
Biomass = 0.4%
Wind = 0.2%
Imports from NSW = 0.1%
Oil = 0.01%
Export to NSW = 8.5% of Qld supply
Vic:
Coal = 74.2%
Wind = 9.1%
Hydro = 5.8%
Gas = 4.3%
Solar = 3.7% (houses etc = 3.4%, large scale = 0.3%)
Imports from Tas, SA, NSW = 2.9%*
Exports to SA, Tas, NSW = 4.4% of Vic supply
*A complicating factor with Vic is that fairly often exports from one state to Vic are ultimately transferred to another state and recorded as such in the other state's figures. The physical quantity imported to Vic as a transit route, eg Tas or SA to NSW, is thus significantly greater than the 2.9% shown. A similar complexity exists with exports.
SA:
Gas = 42.9%
Wind = 39.0%
Solar 9.2% (houses etc 8.3%, large scale solar 0.9%
Import from Vic = 8.5%
Oil = 0.1%
Exports to Vic = 7.1% of SA supply
Tas:
Hydro = 81.9%
Wind = 8.7%
Import from Vic = 4.9%
Gas = 3.3%
Solar = 1.2% (all of which was small scale on houses etc)
Export to Vic = 14.5% of Tas supply
Those figures are annual for the past year.
In the short term however, wild variations can and do occur. Eg looking at the week ahead on the 24th forecast load significantly exceeds supply available within the state in Victoria. There is thus a significant reliance on Tas, SA and NSW to keep the lights shining in Melbourne on that day and not much room for anything to go wrong without ending up in trouble. Ultimate cause = hot weather.
So in the space of a few hours it goes from lots of plant sitting idle to a scramble to find adequate supply. That's a pretty routine occurrence.