Successful operation of distributed generation systems requires controls that can integrate building load, electric generator and grid information in near real time to produce optimal set points for the generator and the HVAC system(s) in the building(s) served by a given generation system. This paper discusses recent developments for distributed generation control in commercial buildings in the context of the U.S. utility industry. Several examples using different building types in different geographical regions of the U.S. are used to show how optimal and near-optimal control provide an economic benefit above simple threshold control. The examples are selected to illustrate the technical approach to system control using typical system characteristics and costs; every system in every location will have its own unique set of control criteria. The objective of this article is to describe the approach, not to solve specific problems.