Certainly I don't expect there to be one source that covers everything, but I've had a hard time finding any sources which felt like they covered things in sufficient depth/detail
Greentech Media used to be really good but they got bought out by some market intel firm and now everything is hidden behind a consultancy. Sad.
I mostly just have a bunch of a keywords on Google News, and look up papers on Scholar if they're mentioned.
Would also be interested in more "push" based sources like newsletters if there are any out there.
(Worked in solar on and off for a decade+, but mostly doing web dev. Don't keep up with the research much.)
That's because my interest and work primarily skew retail (B2C), installer-facing, and mapping, though.
If you're more interested in the field as an investment opportunity for near-future tech, maybe academia would be more the place the look, at upcoming cell chemistries, balance of system costs, manufacturer consolidation and bankruptcies, storage (battery) developments, non-battery storage technologies, etc.?
In my experience, there's been a lot of vaporware in the industry, with new discoveries every year but very little of it ever making it to market. Mostly just year over year improvements in module efficiency, more companies making microinverters or power optimizers, and exciting stuff on the software front for remote site assessments. And of course storage is huge these days.
My read as a grunt in the field is that it's a relatively mature trade that's becoming like plumbing or electrical work, just another infrastructure job that everyone needs. I don't see it as an industry particularly ripe for disruption, but I could easily be wrong lol. If I knew where it was headed, I'd be CEO and not a lowly web dev :)
Sorry I can't be of more help! Happy to chat, but my knowledge is limited to peon level stuff.
For example, I can imagine (though no clue if it exists) some materials science professor who studies something related to materials for solar cells who also has a blog, or some policy wonk who dissects things like FERC rulings on interconnection policy with a view on their implications for integrating new solar developments into the grid.
I've seen things similar to this for other fields I've looked at, but for solar specifically, I have no clue how to find such people, if they do exist somewhere out there.