In practice, the real number is probably closer to 36% than to 65% (and likely even lower).
Here's the problem: the article doesn't account for the capacity factors of the various new installed sources they mention [1]. A capacity factor is the actual electrical energy produced by a generating unit, divided by the maximum possible electrical energy that generating unit could have produced if it were operating continuously at full power. And under real-world conditions, most renewable energy sources produce at far below their theoretical capacity maximum.
For example: wind turbines have a capacity factor around 36%, and solar installations are under 25% [2]. If we apply these factors to correct the numbers in the article, the picture becomes much bleaker: the headline 1475 MW of new wind capacity drops to just 531 MW, while the headline 2530 MW of installed solar drops to 632 MW. Now let's generously assume that the 100 MW of hydro and 29 MW of biomass from the article both operate at a 100% capacity factor. Under those assumptions, total new installed renewable capacity drops from 4134 MW to 1292 MW — more than threefold. [3]
And of course, the real-world shortfall is even worse than this. Electricity markets need to clear continuously, and the capacity factor for solar when the sun isn't shining is not 25%, but 0%. That means if the hours of peak demand coincide with hours during which solar is offline (which they do during much of the year) there is no amount of solar you can install that will keep the grid online. To sum up: there is no way to escape the need for reliable baseload power. [4]
[1] At least, the article doesn't mention correcting for capacity factors. And the FERC source document it cites gives me a blank page when I click on it in Firefox, meaning there is no way to be sure whether anyone applied this correction. I'm assuming they didn't, because citing high "headline" capacity numbers like this is unfortunately very common in discussions about renewable energy sources.
You would not use capacity factor to calculate capacity in the first place, it's the other way around. The 36% guestimate probably comes from somewhere besides these tables. The lower gas capacity factors you quoted are mostly a result of decisions not to run those plants rather than than the energy being intermittently unavailable as happens with solar and wind.
The commenter's point is that although we use the same capacity metric to describe on-demand and intermittently available power generation, it's not meaningful to compare the numbers directly without correction factors.
If I’m reading your comment correctly, 24 minutes of added battery capacity is 1.6% of the number of minutes in a day, which is actually greater than the nameplate capacity increases in solar and wind. This seems more significant than you suggest.
I would also assume that 24 hours is more storage than is actually required given the mix of wind and solar and the geographical coverage of the grid.
How much battery storage, in minutes, is considered “enough”?
Do the battery figures include only batteries or other storage like pumped hydro?
I am not an expert and am interested in knowing why I’m wrong.
Here's the problem: the article doesn't account for the capacity factors of the various new installed sources they mention [1]. A capacity factor is the actual electrical energy produced by a generating unit, divided by the maximum possible electrical energy that generating unit could have produced if it were operating continuously at full power. And under real-world conditions, most renewable energy sources produce at far below their theoretical capacity maximum.
For example: wind turbines have a capacity factor around 36%, and solar installations are under 25% [2]. If we apply these factors to correct the numbers in the article, the picture becomes much bleaker: the headline 1475 MW of new wind capacity drops to just 531 MW, while the headline 2530 MW of installed solar drops to 632 MW. Now let's generously assume that the 100 MW of hydro and 29 MW of biomass from the article both operate at a 100% capacity factor. Under those assumptions, total new installed renewable capacity drops from 4134 MW to 1292 MW — more than threefold. [3]
And of course, the real-world shortfall is even worse than this. Electricity markets need to clear continuously, and the capacity factor for solar when the sun isn't shining is not 25%, but 0%. That means if the hours of peak demand coincide with hours during which solar is offline (which they do during much of the year) there is no amount of solar you can install that will keep the grid online. To sum up: there is no way to escape the need for reliable baseload power. [4]
[1] At least, the article doesn't mention correcting for capacity factors. And the FERC source document it cites gives me a blank page when I click on it in Firefox, meaning there is no way to be sure whether anyone applied this correction. I'm assuming they didn't, because citing high "headline" capacity numbers like this is unfortunately very common in discussions about renewable energy sources.
[2] Capacity factor numbers are for installations in the United States during 2022, from the Energy Information Administration: https://www.eia.gov/electricity/monthly/epm_table_grapher.ph...
[3] From the article: 2530 MW of solar, 1475 MW of wind, 100 MW of new hydro, 29 MW of new biomass, 2259 MW of natural gas.
[4] Even battery installations don't get you there. Between 2022 and 2026, the US is expected to add only 24 minutes worth of battery storage to its grid. This includes residential, non-residential, and grid-scale installations. Sources: https://pv-magazine-usa.com/2022/09/14/u-s-installed-a-recor... https://www.eia.gov/energyexplained/electricity/electricity-...