Argues that the hybrid systems consisting of a combination of electric motor-driven chillers and thermally activated (engine driven or absorption) chillers provide greater flexibility, allowing the building owner to control operating costs by selecting from multiple energy sources (natural gas, electricity and/or steam). Discusses a field demonstration of a chiller package consisting of natural gas, engine, electric motor and compressor which is scheduled for late 1999 at a metal plating factory in Los Angeles. Notes two further product variations based on these three components proposed for further development: 1) dual use of the motor as an induction generator or simultaneous cooling and electricity generation and 2) use of the motor as either an induction or a synchronous generator, thus allowing electricity generation during peak demand periods or for emergency periods.