Genuine question - I wasn't aware of this (fatalities per mwh for wind & solar), what would be the best source to find out more?
https://ourworldindata.org/grapher/death-rates-from-energy-p...
However, be sure to dig into the methodology.
Data on death rates from solar and wind is sourced from Sovacool et al. (2016) based on a database of accidents from these sources.
We estimate deaths rates for nuclear energy based on the latest death toll figures from Chernobyl and Fukushima as described in our article here: https://ourworldindata.org/what-was-the-death-toll-from-cher...
Note that the deaths for nuclear energy include only radiation related deaths, whereas the accidents for solar and wind include "mundane" accidents like workers falling from heights. Nuclear power plants have their own non-radioactive accidents, though, like this one:
https://www.shippai.org/fkd/en/cfen/CB1011025.html
(5 workers killed at Mihama nuclear power plant due to accidental steam release)
I have not seen any comparison that tries to sum up non-radioactive accidents for nuclear power and incorporate them in the deaths-per-TWh rate for nuclear power. The number will still be lower than anything based on combustion, but at these very low numbers it could make a meaningful difference in the relative rates.
Nuclear has far fewer fatalities, but it's accidents are also dramatically more expensive. Although both nuclear and hydro are having their numbers mostly driven by a single catastrophic event (the 1975 Banqiao Dam failure in China and Chernobyl), so how one feels about this whole analysis is going to depend on how likely one thinks future catastrophic events are to be. The numbers are so low that it's hard to come up with very rigorous estimates.
I personally think that catastrophic accidents on the scale of Chernobyl are as close to impossible these days as makes no difference. I'm not even too worried about Fukushima level events (which was not particularly deadly but was very expensive)
However, I have to admit that my opinion on that isn't really backed up be empirics, as is always going to be the case with rare events.
[0]https://www.sciencedirect.com/science/article/pii/S095965261...
https://ourworldindata.org/grapher/death-rates-from-energy-p...
Even using sources from a decade ago, pro nuclear sources like world in data couldn't find any credible sources to back that claim.
And solar and wind were just getting started a decade ago.
[0]https://www.sciencedirect.com/science/article/pii/S095965261...
-edit- yeah after further investigation, according to their "learn more about this data" button, the original source for that data is two publications, the one I linked, and the 2007 paper. The 2007 paper is primirly about comparing nuclear to fossil fuels, and mostly from the perspective of indirect effects from CO2. I'm skeptical of it's claims, as that's a bit too roundabout. The one I linked above is direct effects only (except that it includes cancer deaths from nuclear accidents), which I think goes too far in the other direction. I'd personally include deaths from particulate emissions from fossil fuel generation, but that has no bearing on the comparison between nuclear and wind/solar.
I don't know how they ended up with the plot they display given the sources that they have, but I trust the graphs in the 2016 paper more, which show much larger effects.
In any case, it's certainly not true that there are no credible sources backing up the claim. One can dispute it, I'm sure, but there are credible sources backing it up.