Pepco Energy Services signed the Ridley School District in Pennsylvania to a 15-year performance contract that guarantees nine schools will save one-third off their energy use - about $6.5 million over the life of the contract. PES will install new chillers, boilers and window, control systems, water conservation and lighting upgrades along with training. Construction begins this month and will be finished by the end of the year. PES has developed, implemented and financed $500 million in similar deals for 200 clients since 1995.