An integrated system provides electricity and heat from solar, waste heat, biomass and fossil fuel energy. The system operates with a volatile organic working fluid that circulates in a variable speed heat engine type cycle, that is heated either to its boiling point, to a saturated state or above its boiling point, or to a superheated gas state, expanded through an expander, with working fluid injected therein such that the fluid exiting the expander is cooled in a condenser in thermal communication with a facility's domestic hot water, space heating or process heating systems, and circulated by a pump. Heat exchange loops define hot water production capability for use in a facility while a generator is coupled to the expander to produce electricity and is connected to the utility grid at fixed frequency and voltage in either a paralleling or island mode.