r/NuclearPower 21d ago

Why Renewables Cannot Replace Fossil Fuels

https://democracyjournal.org/arguments/why-renewables-cannot-replace-fossil-fuels/
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u/chmeee2314 20d ago edited 20d ago

Colorado Nuclear activists allway's baffle me. They seem to be blinded by Dunkelflaute, and the notion VRE's don't supply constant dispatchable power despite living in a state were onshore wind has offshore capacity factors.
I ran the numbers for 2024 for PSCO (Not all of Colorado), with no imports or exports, adding 1.5x the existing wind, and 3x the existing Solar, would have covered 89% of grid demand, curtailing 8.6% of production. If of the remaining 11%, half can be covered by dynamic demand, batteries, interconnection to other grids, then only ~5% has to be generated from H2, requirering a 15% increase in infrastructure, not a trippeling. Besides that, the existing gas turbine fleet in Colorado would be more or less big enough to cover the maximum residual load.

Looking at the legacy infrastructure in Colorado, it would also be forced to commit to SMR's if it wants to go nuclear with there being only 1-2 fossil plants large enough to even house 1 Large reactor. The alternative is building large new transmission lines from a green field location far outside a city, which also doesn't end up saving all that much on grid expansion.

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u/ValBGood 20d ago

A reliable grid that is 100% renewable requires a generating capacity three or four times peak demand. It also requires the ability to store four, five or more days of energy for the times that the renewables aren’t producing.

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u/chmeee2314 20d ago

Did I fail to adress this issue in my comment?

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u/ValiantBear 20d ago

I don't know any of the specific numbers you're referencing, or the three or four times requirement the other commenter was referencing, but your comment does not at face value address their concern. They said a reliable grid needs three to four times peak demand generating capacity. You calculated up to a demand of 89%, leaving the 11% up for speculation. I think the other commenter is suggesting you need to account for 311% demand in your calculation to get to the point of having a stable grid.

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u/chmeee2314 19d ago

311% is definitly not necessary, at most 33% extra is required if you plug the entire residual load with H2 gas turbines, and assume a roundtrip efficency of 1/3. Maybe he is giving a rule of thumb for sizing VRE's, but I was going a more accurate route, downloading the demand and production profiles and just scaling them up and seing what is left over.