There are a lot, but it's not the same concept as the Low Tech Magazine site.
Equinix and other big data centres hosting customer sites have multiple levels of power redundancy, if solar isn't providing enough power at any moment then they draw it from the grid, and they probably have diesel generators as an emergency power solution.
Low Tech is very simply some solar panels, a couple of batteries and a web server. It makes for a really interesting study into the amount of power generated and consumed, and the battery monitor on display constantly is kind of fun.
It's kind of a shame that together with the charge/consumption/etc. stats they are not showing active visit numbers because that would be interesting to see how many site visitors are draining how much power.
I *LOVE* these kinds of quirky finds! What a neat concept to power the entire thing based on solar. As long as it's not a mission-critical site, I love the idea - like for a personal site.
"The accessibility of this website depends on the weather in Barcelona, Spain."
As an SEO guy, I never want to see a site offline, but I wonder what kind of notice it throws when it doesn't have enough power. Is there a default redirect to "we don't have power, come back later" or is it a dead site that doesn't resolve?
Do we need to get 10 people together to drain the battery and find out? (Crowdsourcing a crash is never a good idea!)