"His electricity comes from solar panels, and every joule counts — so that’s out with Chrome and Electron and in with Scheme, C, assembly, and maybe someday Forth."

I used to live and program off grid, too. With a setup, I could carry all in my backpack ... so I can say, it mainly depends on the hard- and firmware in use. So my pure linux laptop did not last very long. Even with allmost only texteditor use

But my optimized rugged chromebook does last a long time, and with only modest sunshine -> unlimited worktime - with extensive use of chrome and electron.