I always day dreamed of a way to extract energy from the heat gradient between cold and dark sides. Possibly a huge pipe with a heat exchanging fluid at higher latitudes.

But with the prices on solar in recent years, I think that’s mostly discarded.

Those are local prices. You're forgetting about the expense of shipping, and I'm guessing the last mile problem in that particular set of logistics is a big one. Finding skilled laborers in local manufacturing might also be pretty expensive, so offshoring will be much more favorable even with the higher shipping fees.

You can stand up a thermoelectric panel exactly at the terminator, and collect energy by transferring heat from its day to its night side. The night side would be radiating to -270 degrees Celsius, warmed only by whatever convective air is around.