I have friends who live in shanty towns in Zambia. I can guarantee you that they will be unable to shell out for a solar panel — even if it lasts for 10 years.

I have friends who live in shanty towns in Zambia. I can guarantee you that they will be unable to shell out for a solar panel — even if it lasts for 10 years. I don't know about zinc, but copper is plentiful (in fact, they both live in the Copperbelt Province) and they don't have to pay for all 10 years of copper and zinc in one instalment.