I bought one last summer so I could continue riding pending my left hip replacement. I bought a Tern HSD S8i cargo bike. About $4100 out the door. I have a crate on the back rack for cargo. It has a Gates carbon belt drive and a Shimano IGH, so it requires much less maintenance than my chainline bicycles. It has a step-through frame, so it is great for older riders and/or riders with creaky hips or knees.
If I am riding around town in the hilly Cascade foothills with groceries or beer in the crate, I am getting around 35 miles range. If I am riding on a flat bike trail, I am getting close to 60 miles range. I am a strong bicyclist so I am often riding with no or minimal electric assist, since bicycling is one of my primary means of exercise. I do use the assist on the hills. The downside, as with most electric bikes, is they are heavy. Mine comes in at 64 pounds and you feel that when you are pedaling without the electric assist. A big difference from my titanium road bike that comes in at 21 pounds. I hope to start riding my other bicycles again after surgery.
It came with a Bosch rapid charger, and takes about four hours to charge from empty. I imagine you could plug it into one of the battery generator packs that you in turn charged up from wind or solar. I have been pondering one of those generator packs.