Comment by duskwuff
> I don’t know what factors would make IEA underestimate solar adoption.
The IEA is an energy industry group from back in the days where "energy" primarily meant fossil fuels (i.e. the 1970s), and they've never entirely gotten away from that mentality.
There are trillions of dollars on the line in convincing people not to buy solar panels or other renewable sources.
Remember all the conspiracy theories about how someone invented a free energy machine and the government had to cover it up? Well they're actually true - with the caveat that the free energy machine only works in direct sunlight.