[AnthonyMouse]

> True but having capacity allows for generation - doesn't work the other way around.

The issue is that comparing "capacity" as a percentage is misleading. A baseload generation source can have average generation above 90% of its rated capacity, solar at something like 25%, wind something like 25-40%. Which means that saying "nearly 50%" of capacity can imply something closer to 15% of generation, and potentially even less if the amount of local capacity is high, because then you get periods when renewable generation exceeds demand and the additional generation has nowhere to go, which effectively reduces the capacity factor even more.

And on the other side, natural gas peaker plants can have a capacity factor even lower than solar and wind because their explicit purpose is to only be used when demand exceeds supply from other sources, so that "nearly 50%" in a grid which is entirely renewables and peaker plants could actually imply more than 50% of total generation. This is much less common in existing grids but it makes looking at the nameplate capacity even more worthless because you can't just multiply it by a fixed factor to get the real number.

Whereas if they would just publish the percentage of actual generation, that's what people actually want to know. But then you'd have to say "13%" or "24%" or whatever the real number is, instead of "nearly 50%".

[ninkendo]

> solar at something like 25%

The graph at https://ourworldindata.org/grapher/solar-pv-energy-consumpti... seems to indicate the real world outcome is something more like 12.9%. That is, pick a dot on the graph and look at the capacity (watts) versus how much was generated in 2024 (watt-hours), and the number ends up vaguely looking like 1000 watt-hours generated for every watt of capacity. Given that there's 8760 hours in a year, that's vaguely in the 12% range.

The number for "World" is 2,110,000 GWh consumed for 1,866 GW of capacity, which means 2110000÷(1866×8760) = 12.9% of "capacity". Running the numbers for every country (there's a csv!) shows expected cloudy/northerly countries down near 8-9% (UK, germany, norway) and the sunnier ones near 20%... The USA is 19.8% which tracks given how popular solar is in the sunnier regions in particular.

Nobody in their right mind should be surprised by this, since the sun doesn't always shine, it gets dark at night, etc... it's unrealistic to assume this number will ever meaningfully change for solar. It's just the baseline expectation.

So yeah, "capacity" is misleading indeed. It means that for solar, "50% of global capacity" would mean something more like "6% of energy consumed".

But it's still super exciting to see the clear exponential growth here. (Speaking as someone who installed a 14KW array on his roof last year, solar makes me super excited.)

[AnthonyMouse]

~25% was from the EIA as the US average for utility scale PV:

https://www.eia.gov/todayinenergy/detail.php?id=39832

Rooftop is presumably bringing down the US average, maybe there is more rooftop capacity in the north and utility-scale capacity in the southwest or utility-scale more often uses sun tracking. And as you point out solar output is quite dependent on latitude and clear skies.

> it's unrealistic to assume this number will ever meaningfully change for solar.

Well, sort of. Being dependent on all of those things means it would change depending on where the capacity is being installed and what kind. The world average is ~13% primarily because China + Europe represents around two thirds of current capacity and China has a shockingly poor capacity factor for its latitude whereas Europe has the expectedly poor capacity factor for its latitude -- how did China manage to get a lower capacity factor than Finland or Russia anyway?

But go install a lot more utility-scale capacity in the US Southwest, India, Australia, South America, etc. and the world average would move up by a non-trivial amount.

[boringg]

The point is that its a proxy for more renewables being deployed on the grid. Thats the take away. It is a piece of good news. From one fellow energy nerd to likely another one - don't get hung up on the details. There is still a lot of work left to do.