Disclaimer: I've only had my EV for about a month and usually charge at work or home so haven't got that much experience with public charger etiquette.
I wouldn't think 4 hours a week is "hogging it" but I would think the etiquette somewhat depends what 4 hours you are there. If your 4 hours coincidence with the peak usage of the charger (maybe when people are checking in for example) that is different to 4 hours when nobody is there anyway.
I agree that a mix of energy sources is a good idea. Maybe a mix of wind, solar, hydro...
Batteries isn't an energy source, it's energy storage. We can generate electricity in many ways.