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 buffer that solved the intermittency problem all on its own. I wanted the renewable power provided by this mod to have unique features, but remain both balanced and realistic, particularly in relation to (photovoltaic) solar panels.
• I don't particularly like having tiers of entities that will only be used in the early game, and since the basic thermal panel is already pushing realistic limits of what could be achieved without a concentrating solar tower, I decided to simplify the mod by removing all higher tiers of the thermal panels, heat exchangers and steam engines.
• The Heat Accumulator (and by extension the Evaporation Pond) has become entirely useless 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, 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. The mod has been updated to work with Quality in Space Age so the heat output of the panels scale with quality tiers (finetuned to roughly match the scaling of Solar Panels). The optional adaptation for Pyanodon provides parity between the Basic Heat Exchanger and the Boiler.

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 (1.6 ms/tick with coal backup), which works fine for me.

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. At the default output of 67.5kW, efficiency is ~52.5%, increasing towards ~70% with higher values, but dropping to 0% at 37.5kW, since the threshold for steam production can no longer be reached.

Q: Will you make any further changes to the mod?
A: I will likely do a bit of tweaking still. Nothing major.