An Earthship is an off-the-grid home built from tires rammed with earth for thermal mass (the earth is a constant 57 degrees) heated and powered by the sun.  The roof collects rainwater which is re-used to water indoor  greenhouses  that grow food and flowers.  I have been living in mine for a dozen years and have tomatoes growing in my bedroom!  I can't imagine living any other way now.  No need for utility bills when the earth gives us what we need for free!