[paganel]

> Solar powered AC works just fine without a power distribution network and even tends to track production and demand

It's pretty hard close to impossible to scale that to large and dense communities. I know for sure that my Eastern-European city (population: ~1.8 million) has enough problems as it is when in the summer heat people turn the AC on at the same time. And we're a pretty ok country in terms of power distribution, I'd dare to say, we have hydro, nuclear, wind, and of course coal-based energy.

More to the point, I fail to see how you can provide power to an African city with a population with 2 million (let's say) only using solar. I know that there's a lot of sunny days in sub-Saharan Africa, but you need to have huge solar farms, for which you need political stability (so that people don't destroy said farms), you need power lines that would bring said solar-generated power to the city (which also requires political and economical stability), you need engineers (preferably locally-trained, that way the costs are manageable) in order to manage all that, you need to make it easy for people to pay for it all (again, this requires institutional stability) and so on and so forth. I'd say that there are still large swaths of the world where all these conditions don't apply.

I'd say people here on HN have a slightly skewed perspective on things. Most of them have grown up (and some of them still live) in American suburbia where having the possibility to install your own solar-power thingie is totally feasible. But American suburbia it's not the whole world.

[hx87]

> I know for sure that my Eastern-European city (population: ~1.8 million) has enough problems as it is when in the summer heat people turn the AC on at the same time.

I assume though that your city has a district heating system that works fairly reliably in the winter. If that is the case, why can't a district cooling system work just as well? All you need is a source of heat (which you already have, courtesy of district heating) and a heat sink--either cooling towers or a large body of water. If a society is prosperous enough to provide district heat, then it is prosperous enough to provide district cooling.

> in American suburbia where having the possibility to install your own solar-power thingie is totally feasible

It's actually easier in some ways to install solar panels on a residential building in sub-Saharan African country because regulatory restrictions either do not exist or can be circumvented with a wad of cash. A reasonably priced solar setup on a house or flat may not be able to satisfy its entire electrical load, but it can certainly provide enough energy for air conditioning.

[Retric]

People are actually doing this right now due to terrible power distribution networks.

If you work out power needs, you can do AC with rooftop solar up to ~5 story buildings. Building past that point need real infrastructure. But, getting water and sewage is much harder to get working in a city that size than power.

A larger issue is solar has a relatively large upfront cost which is prohibitive in poor areas and ripe for theft.

The low end for AC is probably a 1kW system which can keep ~1,000+sf reasonably cool and runs some lights for well under 3,000$* in materials and the solar should last around 15-25 years. Costs will go up if you have a lot of people or equipment in that space, excess humidity, or want large temperature changes but this is just a baseline. Wiring up for more apartments is fairly simple, but your going to run out of roof for tall buildings.

*Costs without battery storage or grid tie in are far lower.

PS: Most people would want more than just AC and very low power lights. But, costs actually drop per watt as you scale, and installation does not take much in the way of training.

[hx87]

You can also put panels on walls as long as they have adequate solar exposure.

[Retric]

Near the equator you’re going to get minimal power that way, but further north or south you can get a fair amount of power on one side of a building assuming you’re not shaded by other tall structures. Street level in Manhattan for example gets less sunlight than you might think. You also run into a tradeoff with windows.