caraher,
Notice that everything you quote above is talking about how to meet the 20% that the NAS says we can do!
Evidently you didn't read the whole report if you missed the parts where they told you that 20% was the limit.
The main problem is the Law of Conservation of Energy. The generators on the grid have to match the demand instant by instant; not averaged over a day or a few hours; but by the instant.
Suppose the renewable generators are putting out 1 Gw(e) = 1,000,000,000 watts. However, suppose the demand goes up by just 1 watt; so the demand is 1,000,000,001 watts. Suppose the renewables are "maxed out" - they are generating all the energy that they are receiving from Mother Nature. It's just that the demand exceeds that by 1 watt.
Therefore, in a single second, the renewable generators will have put 1,000,000,000 Joules of energy into the grid. However, the load will have received 1,000,000,001 Joules of energy from the grid. In other words, the load will have received 1 Joule more than the renewable generators provided.
Where did that extra 1 Joule of energy come from? The generators didn't create it. The grid can't create it.
It's a violation of the Law of Conservation of Energy - it is creating energy out of nothing.
Mother Nature won't allow that; and before she lets that happen; she will COLLAPSE the grid because it's about to violate Conservation of Energy.
This is what the "greenies" don't tell you; their system can't respond to demand like the dispatchable power sources of coal, gas, hydro and nuclear can. The renewables need the dispatchable power sources of coal, gas, hydro, and nuclear to do the load following that renewables are INCAPABLE of doing. In order for the system to be stable; the dispatchable load followers have to out number the non-dispatchable renewables by about 4:1; hence 80% dispatchable generators, and 20% non-dispatchable renewables.
It's all there in the report. Evidently, you didn't understand it when you read it. That's why having a degree in the sciences is necessary.
See also:
http://en.wikipedia.org/wiki/Dispatchable_generation
The NAS report doesn't present the 12-20% as a limit; besides nuclear power exceeds the 20% now; and in the recent past nuclear exceeded 25%.
The good thing about science is that it is true, whether or not you believe in it.
--Neil deGrasse Tyson
PamW
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