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Scary to think that a wet 2014 caused China to burn less coal as the hydro facilities were running full steam
That would be full gate, not full steam....
The thing about hydro is that if you've got decent storage then you can certainly overproduce in any given year or even for a few years if there's enough stored water. But you can't do it forever, at some point outflows and inflows must balance otherwise the lake dries up.
Hydro - except in a flood big enough to actually fill and spill the dams, output is energy constrained. That is, it's limited by long term average inflows.
Coal, oil, gas, nuclear - under normal circumstances generation is, in the medium term at least, limited by capacity of the power stations. That is, under normal circumstances you can get hold of as much fuel as you want, so that's not a limit but rather, the limit is the capacity of power stations to turn that fuel into electricity.
The Tassie hydro system is humming along nicely at about 185% of its long term capacity right now. No way can we keep that up indefinitely, but local (Tas) demand is above average right now and the spot price in Victoria isn't too bad either at around 4 cents / kWh, so it makes sense to run the system hard and make some $. Whilst the system could certainly maintain that output for quite some time, ultimately over the long term it can't run at more than 100% of long term capacity otherwise the result is empty lakes. Whatever is borrowed today via high rates of production, must at some point be paid back by lower rates of production. Same concept everywhere and that includes China.
I saw some survey results today regarding Australian public support for various means of generating electricity.
Solar (small eg rooftops) = 87% of people support it.
Solar (large scale) = 78%
Wind = 72%
Hydro = 72%
Tidal = 52%
Geothermal = 45%
Nuclear = 26%
Coal = 23%
Don't bother mentioning oil or gas as most seem to have worked out that they're duds in anything other than the short term.
As for coal in China, I wonder how much of their actions are based on concern about the climate and how much is based on the pragmatic reality of conventional air pollution and that China's coal reserves are, by most accounts at least, rapidly diminishing. You can't keep mining 3 billion tonnes of coal for too long when you've only got 60 billion tonnes of high grade coal, and another 50 billion tonnes of sub-bituminous and brown coal. Sooner or later, production peaks whether you want it to or not.