Q: Is this a mod of excellent quality?
A: It seems pretty all right! Mind you, I am not a programmer, and there are various limitations with the game engine that forced me to rely on small hacks for some of the mod's features. But I have taken a long time refining this mod even after its release, to ensure its function.

Q: Why did you remove so many things from the original mod?
A: For more realistic balancing, and to declutter.

• The tech can be researched early on, but even the basic tier of thermal panels easily out-competed alternatives with high output and a large internal heat storage solving the intermittency problem all on its own. I wanted the renewable power provided by this mod to have unique features, but remain balanced. I also find tiers boring, and don't like adding entities that will only be used in the early-game. So I removed all higher tiers of thermal panels, heat exchangers and steam engines.
• The Heat Accumulator (and by extension the Evaporation Pond) has become even less useful due to the new heat loss mechanism, and the same goes for the Recycler with the removal of tiers (also, Reverse Factory exists). So I removed all these as well.

Q: The information in the tooltip for the panels seems a bit odd!
A: That's not a question. But yes, there is some useless information mixed in due to prototype constraints, which are hard-coded. With some small hacks I managed to properly display the max heat energy output and even create a makeshift sunlight indicator inspired by Cheese's Concentrated Solar! To ensure good performance with many panels and avoid some potential issues with on_tick scripts, it only displays a snapshot of the current light level while its gui is open. It works by emptying and then filling the buffer with a proportionate amount of "solar-fluid" (the fluid content goes down ever so slowly, since only a consumption rate above 0 is allowed). The fluid could remain on crash, death, disconnection or switch to spectator mode while the gui is open, but it's inconsequential and easily resolved by clicking the entity again (or by using the reset command).

Q: How is mod compatibility?
A: That is hard to say with Factorio 2.0, but it's probably fine. There is a small, optional adaptation for Pyanodon so The Basic Heat Exchanger better matches the Boiler.

As for earlier versions of the mod: I created optional adaptations for Bob's Power, Fantario, Industrial Revolution 3, Krastorio 2 and Space Exploration. Balancing can be very difficult, and the mod can't keep up with their scaling, but I at least tried to give the thermal solar complex rough parity with the first tier of Solar PV + Accu.

Regarding other mods: Nullius seemed to prevent the activation of this mod's content no matter what, for reasons I haven't figured out yet. With Realistic Reactors installed, removing thermal panels or heat pipes could cause a crash, and I have no idea how to solve the problem on my end. Who knows, maybe it has been solved already.

Q: What is the performance impact on the game?
A: For the sake of my creative goals, there is a fairly complex temperature script being applied to every thermal solar panel once every second, and then there is related management of heat, fluids, entities etc. On my PC (i5-12400F, RTX3070) it seems that producing 1GW of electricity around the clock with only the solar thermal complex (and no coal backup) could increase CPU time usage with an average of maybe 5.3 ms/tick. Using the large version of the Thermal Solar Panel, that is reduced to about 1.3 ms/tick, which works fine for me. (Note: Overall performance may have improved slightly with the new fluid handling system in Factorio 2.0.)

Q: Anyway, how do you calculate the actual, average output of the thermal solar panel?
A: You can use the formula below, which was obtained by regression on a few experimental data-points:

AverageOutput = OutputSetting*(0.7-7/(OutputSetting-27.5))

It only applies when the Basic Heat Exchanger's target temperature is at its default setting of 165°C, though.

Q: Will you make any further changes to the mod?
A: I don't have any real plans right now. I have thought about improving graphics at some point. I could be interested in adding content that helps increase power production efficiency a bit further with more complex setups in the late-game, but I also want to be super careful not to break game balance, ruin the mod's aesthetics or muddle the theme of it. Anyway, in relation to vanilla Factorio, the mod feels largely complete as it is now.