It's uncommon, but a wind generator can help a lot: in some climates, cloudy days tend to be windy days. Not really practical in a city though.

> It's uncommon, but a wind generator can help a lot

It's uncommon for a reason. Wind generator capacity rises with the square of the rotor diameter. That means small-ish generators (let's say "small enough to be roof mountable without additional mechanical supports") are significantly below 1 kW of power. Seriously, the systems people by for their sailing yachts make around 50W from a nice breeze - enough for lights and to trickle charge the battery while docked, not nearly enough for a fridge.

Combine that with quite a number of moving parts, changing loads and exposure to weather, you get very short maintenance intervals and final lifetimes.

If you have any other option for power, its almost always economical to just use that.

The AMC White Mountain huts have been doing this for years. The croo don't tend to maintain the systems, so I've never gotten a sense for what their storage capacity, generating capacity, and loads look like, but from a visitor perspective, the system works well.

Reportedly, even the fairy stout wind turbines they use up there have short, brutal lives. I heard the story of a croo that had to lasso/tangle/jam the blades of theirs in a storm because it lost the ability to control its speed and the alternative was letting it overspeed and possibly tear itself apart. They aren't large in diameter, but at the speeds they turn even in normal conditions up there, catastrophic failure could be really bad.