An energy-efficient system that runs on city gas, generating the power and heat where they are used such as homes and businesses, and using the waste heat from the system to heat or cool the air, or to heat water. Electricity is generated by kinetic energy from gas engines and gas turbines, and by fuel cells, which are powered by a chemical reaction between hydrogen and oxygen. Two types of energy, electricity and heat, are generated from these systems fueled by a single energy source.