Question

2.
How energy is used at homes, communities or cities in relation to sustainability principles?​

Answer 1

I guess the answer to this question will vary a lot according to the country or community we're talking about.

Considering Brazil, where most of the energy used to maintaining the country is from eletric sources, there's not much to say about sustainability and its principles, since this method does bring side effects to te environment, unlike eolic energy, for example.

The use of this energy in Brazil is mainly liked to keep industries going as well as providing the so called basics to the Brazilian families, light, air conditioning, cooking, heating and so on, according to people's needs.