That leaves thermopiles.... without going into the math, just no.
From memory, I worked out that one thermopile = 1/40th of the power of a wind turbine. After that, for lulz I built four towers of 48 thermopiles each, in creative. I've become somewhat used to absurdly nerfed power systems in this game at this point; but even that was rather silly.
For me, the best parts of RP were the wiring/integrated circuits, the project table, and the gems for tools; and when I look at it now, that was actually pretty much it. I used some retrievers in 1.2.5 which were fairly cool, but nothing you couldn't do in BC; although admittedly in BC there would be more screwing around, since RP's second tier stuff is MUCH more power efficient.
I also back-engineered someone's design (again in Creative) for a non-inchworm frame-based mining machine during 1.2.5, as well; but it was purely for lulz/to teach myself how to do it. There is no way known that I would ever use that in Survival or a legit/production world. I wrote a control interface for it, but did it in Lua with ComputerCraft, since FORTH is hell; and it needed wireless redstone in order to really be worth it, as well. It did have one advantage; the design I made was (relatively) miniaturised, and if I had built several of them side by side, I could have very easily run them in parallel with the wireless redstone interface. Doing so would have caused quarry users to curl up into a foetal position on the floor and cry, in terms of the difference in mining capacity.
The other single main strength of Red Power 2 was (and I will always defend it for this) the fact that it was almost completely generic. It was written to interact with Minecraft's physics or blocks at a universal level, not in terms of specific use cases. I can use block breakers for a mining machine, or I can use them to cut down trees, and as far as the mod is concerned, it doesn't know the difference. While I love Minefactory Reloaded, I've read PowerCrystals admitting that he has written targetted edge cases for numerous things; and edge cases are always less robust than generic design, by definition.
In that sense, RP2 to me was largely unique, and provided a glorious example of UNIX design philosophy in the process. In terms of how she fairly obviously thinks, I've often quite seriously had the thought that if I ever meet another woman with a similar mindset (in the technical aspect) to Eloraam's offline, I'm going to put genuine effort into marrying her.