The basic idea (bartering power/recharging) is not actually far fetched. I've seen exactly that done in overseas locations. But you have to realize that the local security situation drives the train. Disaster conditions can be brief... or stretch into a long term state of normal.
During a transient event (hurricane or tornado aftermath), you're not going to win any friends by charging folks to plug in at your location. Quite the opposite.
During a longer event where rule of law, power grid, or a normal economy breaks down (e.g., post-Hurricane Katrina or war torn Bosnia), you'd better be able to secure/defend your offered service. Meaning that you'll likely need relatives, neighbors, or friends to help you accomplish that. Or the patronage of local authorities (whoever they might be, lawful or unlawful). Because eventually, somebody is going to come along and just demand power at gun point. Maybe haul off your power generation gear (along with whatever else they fancy).
In rural Afghan villages/towns, local recharging stations were/are very common. Much of the populace owns cell phones, but functioning electric grids are nearly non-existent outside of larger urban centers. So entrepreneurs establish electric charging points at cafes, auto repair shops, or gas stations. Run by generators made from converted automotive engines.
Everyone knows where they are located and they are generally unmolested by armed factions/gangs, because everyone needs the service. But that means that those same local armed factions take a cut of the profits in return for ensuring local security. Straight up mafia control of businesses. In Afghanistan, people with guns and money own generators. People without either... don't.
Local fabrication shops & automotive repair garages do a lot of business converting Volvo or Toyota engines into welded frame mounted household generators. A very common sight everywhere in the country. I once lived in a town of 50K+ that had never had an electric grid in its entire history. Power lines and central power generation simply didn't exist. Living pretty much the same as their ancestors had for thousands of years. Still using oil lamps and candles at night. But people had Toyota trucks, AKs, cell phones, and access to limited (but adequate) amounts of trucked-in fuel. Which ran generators for those who could afford them.
In northern Bosnia, I lived on the economy in a spacious rental Serbian house. Power was intermittent (frequent outages or brownouts). At least a weekly occurrence. So we had backup generators. Little inverter Hondas. Bigger framed models. And a locally fabricated whole house unit powered from a truck engine. We improved relationships with our adjacent neighbors by running extension cords into their homes to keep essentials running year round. We had a lot of generator maintenance for our multiple units, but the fuel & mechanic services were paid for by my employer and reliably delivered. Providing power to long established neighbors was a bit of a local security insurance policy. They became our friends. Friends who could warn us of impending armed trouble or feed us local gossip/intelligence.
Bartering rechargeable power is a balancing act. As long as everyone understands there's no free lunch, you can get folks to pay/trade. But you'll require a security environment that ensures you don't get sabotaged (out of jealousy) or robbed. If the power is out for the long term, expect to be paying somebody "the bite". Because in a land without reliable power, anyone selling/bartering such is a ripe target for extortion, theft, or taxation. Unless you own (or rent) all the guns and manpower to defend your little enterprise.
The excess solar power gig could work, but things have to be stable enough that folks don't get desperate about it. It also invites strangers (with a believably legal excuse) right to your doorstep, which might not be such a wise idea. Might be better to offer such a service at your local post-event flea market/farmers market instead. Where, once again, somebody else will be enforcing order and providing immediate security.
In the 3rd & 2nd world, such venues always have some hired armed muscle on hand (working for the owners/managers) to ensure that business transactions/barter flow without drama. Anyplace where profits are turned, somebody will ensure that they are positioned to take a cut... and protect their cash/trade cow. It's actually a good thing, but you'll be charged rent to occupy secured vendor space. Might need to recharge management/security force devices for free. Expect it.
During a known short term event, I'm taking care of neighbors & friends out of good will. For free. Things are going to get better in the near term, but it could take decades to reestablish good relations with folks you once took advantage of... or to whom you denied aid.
