3 ms·

> 1. That plant produces ~392 megawatts in a year. It produces 640 gigawatt-hours in a year. Power in a year doesn't make sense, and it doesn't make its namep

by mlyle 2y ago

> 1. That plant produces ~392 megawatts in a year. It produces 640 gigawatt-hours in a year. Power in a year doesn't make sense, and it doesn't make its nameplate power all day long.

Terr_ 2y ago
Updated to make it clear that it occurs alongside the year-unit for scaling bird deaths and then coal-usage, rather than per year.
- amluto 2y ago
  You might want to try reading the whole post and further editing. And you should consider avoiding all the weird scaling and working in units of energy. For example: > ~65 kilowatts provided per dead bird. This is incoherent. BTW, Wikipedia says the annual net output is 856 GWh, so it’s 143 MWh per bird killed. You’ve forgotten about capacity factor.
  - foxglacier 2y ago
    It's mind-boggling how consistently almost everyone is confused about energy and power units and makes meaningless calculations and claims. People make this kind of mistake pretty much every time there's an energy story. Journalists too. It is confusing but a little red flag appears in my head whenever I try to do this kind of math. It would be nice if we used energy as the main unit and energy/time for power like in SI. Rates seem to be more intuitive than integrals.
    - Terr_ 2y ago
      IMO the number one biggest contributor to this problem is "watt hours", it a cursed unit, a name which sows confusion. Even if it were named nonsense like "floops", the world would become a better clearer place. It automatically sounds as if it involves watts, hours, or even watts per hour, but it's actually none of those things. It's just (joules * 3600), where that fixed multiplier comes from a quirk of history in how we subdivided our clocks. My advice? Whenever you see it, replace it with "jumbojoules", as in "I used 87 kilo-jumbojoules running that appliance this month."
  - Terr_ 2y ago
    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.
    - mlyle 2y ago
      > 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.
    - amluto 2y ago
      > 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.
Terr_ 2y ago
> It produces 640 gigawatt-hours in a year. While it's true that my napkin-math uses it's planned max output, this correction is not accurate either: That figure seems to refer to only a portion of the generators running on the site, and it also involves contracts rather than what was delivered. Instead let's look at Wikipedia's the "Production" > "Ivanpah total" for the year 2022, which is 769,164 MWh across that year. Convert to joules, divide by the seconds in a year, and that's an average output of 87.74 megawatts. That's down by a factor of ~4.47x from my original napkin-math, so we can just apply it to the coal-amount, giving us a revised "Is mining and burning ~21.9 tons of coal gonna kill a bird?"

by mlyle 2y ago

> 1. That plant produces ~392 megawatts in a year. It produces 640 gigawatt-hours in a year. Power in a year doesn't make sense, and it doesn't make its nameplate power all day long.

Terr_ 2y ago

Updated to make it clear that it occurs alongside the year-unit for scaling bird deaths and then coal-usage, rather than per year.

amluto 2y ago
You might want to try reading the whole post and further editing. And you should consider avoiding all the weird scaling and working in units of energy. For example: > ~65 kilowatts provided per dead bird. This is incoherent. BTW, Wikipedia says the annual net output is 856 GWh, so it’s 143 MWh per bird killed. You’ve forgotten about capacity factor.
- foxglacier 2y ago
  It's mind-boggling how consistently almost everyone is confused about energy and power units and makes meaningless calculations and claims. People make this kind of mistake pretty much every time there's an energy story. Journalists too. It is confusing but a little red flag appears in my head whenever I try to do this kind of math. It would be nice if we used energy as the main unit and energy/time for power like in SI. Rates seem to be more intuitive than integrals.
  - Terr_ 2y ago
    IMO the number one biggest contributor to this problem is "watt hours", it a cursed unit, a name which sows confusion. Even if it were named nonsense like "floops", the world would become a better clearer place. It automatically sounds as if it involves watts, hours, or even watts per hour, but it's actually none of those things. It's just (joules * 3600), where that fixed multiplier comes from a quirk of history in how we subdivided our clocks. My advice? Whenever you see it, replace it with "jumbojoules", as in "I used 87 kilo-jumbojoules running that appliance this month."
- Terr_ 2y ago
  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.
  - mlyle 2y ago
    > 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.
  - amluto 2y ago
    > 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.

Terr_ 2y ago

> It produces 640 gigawatt-hours in a year. While it's true that my napkin-math uses it's planned max output, this correction is not accurate either: That figure seems to refer to only a portion of the generators running on the site, and it also involves contracts rather than what was delivered. Instead let's look at Wikipedia's the "Production" > "Ivanpah total" for the year 2022, which is 769,164 MWh across that year. Convert to joules, divide by the seconds in a year, and that's an average output of 87.74 megawatts. That's down by a factor of ~4.47x from my original napkin-math, so we can just apply it to the coal-amount, giving us a revised "Is mining and burning ~21.9 tons of coal gonna kill a bird?"