Say you're in a place either 15 degrees north or south of the equator where average temperatures are over 25C (77F), a large majority of days are either cloudy or rainy and there isn't any wind. You need 50Wh a day for your needs and the battery you have happens to have a capacity of 50Wh as well so you need to generate every single day. You can buy things but not a battery with a larger capacity or fuels such as petrol. How do you generate electricity? (can either use retail products or late stage experimental technology) I'm currently thinking of going for some sort of wide spectrum solar cells which are receptive to IR and UV as well a larger portion of the visible spectrum but I have no idea if this technology currently exists in the real world. Also, how much less electricity will a normal solar cell generate on a cloudy day? This isn't homework, it's a voluntary problem solving project for us to do that doesn't effect our final grades but does have nice rewards.