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

AKA the forward march of progress.

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> 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%".

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> 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.)

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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.
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A lot of renewables have intermittent generation. If daytime electricity demand is already saturated, adding more solar panels increases capacity but doesn't increase generation (or to be more specific, it doesn't increase generation that actually fulfills demand).
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Unless you add battery storage, which is increasingly the case:

https://pv-magazine-usa.com/2026/02/25/solar-and-storage-to-...

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I'm too lazy to double check the numbers, but as far as I remember, Germany in order to increase it's average generation by 10% had to expand capacity by 70% in solar plus wind. With stats like this, there's a thin line between progress and waste. And all this while we have nuclear. (How the world really works, Vaclav smil if anybody is less lazy than me)
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> With stats like this, there's a thin line between progress and waste.

Humanity does far more wasteful things than build some extra solar panels.

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I would say as electrician in Bavaria: there are enough empty roofs for solar. Especially in poorer neighborhoods. I saw similar numbers and they are scary: to reliably replace conventional power plant one needs 20x the power of wind and solar. And this hardware must be imported from China, there is no large scale production of solar equipment in Europe.
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We can also time shift many of the things we do. Does your fridge need to run between 3-5pm in the heat of summer? or can it make sure its a little cooler to avoid running then? (trivial example, probably not a good one)
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I'm sure there are better examples, but your fridge idea doesn't work. Fridges already operate on the edge of freezing, so if you make it a little cooler you will ruin all your food. Also 3-5pm is peak hangry time.
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A modern fridge also uses approximately five watts, on average. There are far better targets.
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Demand response for things like hotel air conditioning is a thing: https://www.bbc.co.uk/news/science-environment-23343211
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Batteries are also getting cheaper and cheaper
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This is why a major part of the solution is electric vehicles. Why put batteries in a warehouse and then run vehicles on petroleum when you can put batteries in a vehicle, install twice as many renewables because you now have more demand for electricity, and then charge the vehicles when generation is a large percentage of rated capacity and still have enough to run the rest of the grid when it's a smaller percentage?
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And they are the only real solution. Demand fitting production is never going to work unless we give up all the autonomy.
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You have to massively overprovision some renewables
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This is correct in the sense that, if you were to build a zero emissions energy system from scratch with today's technology, your conclusion would be that you'd eventually have to do this.

But in much of the world, setting up PV is economically sound simply because it displaces a certain amount of kWh generated over the course of a year from other sources that are more polluting and more expensive.

In this regime, the dynamics of production over time don't matter yet.

At some point, when renewable generation has very high penetration, you'll reach a point where building more is uneconomical, and to then displace the remaining other power sources you'll need to overpay (ignoring externalities).

However, that's assuming no technological change on the way there, which is a whole separate topic.

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So massively overprovision them. It’s still cheaper than fossil fuels, especially if you price in all the externalities. Seems like all these hungry datacenters we’re building can soak up any excess capacity anyway.
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What does cheap mean? You aren't paying for the same thing - a ccgt plant is super fast and works independent of the weather.

I'm in favour of having it but the reason why you need to over provision is because of the intermittency. This can also push out proper base load (e.g. nuclear) although it's not simple.

You have to think about the portfolio.

In Britain at least there is also a bit of a sleight of hand where the marginal costs are reported but not the CFD strike prices used to incentivise the buildout.

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Can't have generation without capacity...
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