Then run parts at 105-110% and it gets really hard.
The power industry designs a grid that runs so close to capacity that if^W when something big fails, the whole grid shuts down in a cascade. They know it:
Rubbish again.
Welcome to the wonderful world of physics. Ask your favourite physics professor what does
E1 = E2
in context of yesterdays events.
That's not really answering the question, and it's also not entirely right. For one, even if we naively accept sum(Eproduced) = sum(Econsumed), that says nothing about the amperage which can safely traverse parts of the grid intertie wiring, switching facilities, etc. If *those* are running at or slightly over capacity, and in particular of all those facilities don't have at least N+1 and preferably N+M redundant actual capacity, then a single point failure will produce a fatal cascading failure in the system. That appears to be what happened. For two, most of the things that consume power are not in fact consuming exactly a fixed amount of power. Light bulbs go dimmer if you reduce voltage; electrical motors will produce less power (torque X rpm) if voltage drops, etc. Minor blips are happening all the time in major grids, and the voltage is continuously varying up and down slightly. If we had to keep voltage exactly constant, a real AC power system would be nigh-on impossible to build. Our concerns with electrical capacity in terms of the interchange grids having N+1 or N+M capacity, and having systems with enough robustness and graceful failure modes, and having systems with enough reserve generation capacity are all legitimate. A lot of other people are looking at that now, too. But you *can't* just simplify this to Ein = Eout. -george william herbert gherbert@retro.com