They want to avoid critical outside dependencies. For example relying on the electrical grid is avoided because that would be overly dependent on a single outsi

They want to avoid critical outside dependencies. For example relying on the electrical grid is avoided because that would be overly dependent on a single outside supplier. But using electrical devices powered by batteries or generators or solar panels is fine in many of those communities because there are multiple suppliers of all of those (and in the case of generators for the fuel to power them).