You misunderstand, the two hypothetical power plants have an equivalent instantaneous power output in watts. It does not matter how long you choose to sit around staring at them, they're doing their steady-state thing in the background, forever. It doesn't matter to them whether the next calculation involves a halfday or a fortnight.
The "year" aspect comes into play for taking "solar-fried birds per year" (given to us) and "coal burned per year" (calculated from wattage) and then canceling out the year, leaving us with "solar-fried birds per coal".
> you should consider avoiding all the weird scaling and working in units of energy [...] the annual net output is 856 GWh
You're the one doing weird stuff here: Even as you say to use units of energy, you are actually using a unit of power, since "annually" means per-year! Choosing to use cursed units (1 watt-hours vs 3600 joules) just makes it even harder to realize what's going on because the word "hour" is hanging out there as a red-herring.
> capacity factor
Fair enough, I inserted Wikipedia's value for planned/rated level of operation, rather than the much-reduced level it was actually operating under for various reasons.
> It does not matter how long you choose to sit around staring at them, they're doing their steady-state thing in the background, forever.
This is simply not true. Very few power plants work like that, and Ivanpah is definitely an exception. (This is why the capacity factor isn’t 100%.)
> > capacity factor
> Fair enough, I inserted Wikipedia's value for planned/rated level of operation, rather than the much-reduced level it was actually operating under for various reasons.
No, and you might consider reading the article on capacity factor (and don’t stop at the first paragraph - read the section on renewables). If you put 1kW of solar panels on your roof, you are not getting 1kW times 1 year of energy every year — not even close.
And you are replying to my objection to:
> ~65 kilowatts provided per dead bird.
If Ivanpah could kill a bird, once, to produce 65 kW forever, that would be an unbelievably good tradeoff. But, of course, that’s not what Ivanpah does, and saying that years somehow enter the mix later on doesn’t make this statement any more coherent.
And most "napkin math" refers to a simplified calculation with rough guesses made in an impromptu or amateur fashion, like using a pen to write with no options nearby except a disposable paper napkin.
> > canceling out the year
> If Ivanpah could kill a bird, once, to produce 65 kW forever
The context is to get ratios between (A) scope/benefit as indicated by wattage and (B) birds-deaths, and (C) coal-used. If you double the activity of each plant, you can expect one to double the fried-birds, and the other to double the coal-needed.
It feels like I'm comparing dollars-costs of running electric versus gasoline engines of the same "horsepower", and you're unsatisfied because "a gallon of gasoline can't burn forever."
> And most "napkin math" refers to a simplified calculation with rough guesses
Assuming that it's always high noon when you're talking about solar power plants is more than a little rough for napkin math.
> The context is to get ratios between (A) scope/benefit as indicated by wattage and (B) birds-deaths
I give up. The wattage of a power plant is its benefit per unit time, and bird deaths are a detriment not per unit time.
and (B) birds-deaths, and (C) coal-used. If you double the activity of each plant, you can expect one to double the fried-birds, and the other to double the coal-needed.
> You misunderstand, the two hypothetical power plants have an equivalent instantaneous power output in watts.
Yes, but they have different capacity factors. That is, the solar plant is not producing power at night, but your calculation gives it credit for it.
It's best to just keep sane units; e.g. say this plant generates 3 petajoules each year, and kills 6000 birds/year, so it kills one bird per 500 gigajoules.
A coal plant is about 33% efficient, and coal has about 30MJ/kg of specific energy; so we get about 10MJ of electrical energy/kg. So each 50,000 kg of coal mined and burnt would produce the same amount of energy that Ivanpah does between killing birds.
The "year" aspect comes into play for taking "solar-fried birds per year" (given to us) and "coal burned per year" (calculated from wattage) and then canceling out the year, leaving us with "solar-fried birds per coal".
> you should consider avoiding all the weird scaling and working in units of energy [...] the annual net output is 856 GWh
You're the one doing weird stuff here: Even as you say to use units of energy, you are actually using a unit of power, since "annually" means per-year! Choosing to use cursed units (1 watt-hours vs 3600 joules) just makes it even harder to realize what's going on because the word "hour" is hanging out there as a red-herring.
> capacity factor
Fair enough, I inserted Wikipedia's value for planned/rated level of operation, rather than the much-reduced level it was actually operating under for various reasons.