How to Build a Low-Tech Website? : LOW←TECH MAGAZINE
This was a really fascinating post about trying to make a web site—from design down to the hardware that powers it—as energy efficient as possible. This is certainly at the extreme end of optimization, which is what made it so interesting.
They do admit that since the server is powered via solar, it's possible they may have some downtime. I bet they could provide themselves with another layer of protection with a small service worker.