Aggregating Distributed Generators

Electrotek Concepts, Inc., Long Island, NY


In New York State, backup generators that are installed in many commercial, industrial and institutional facilities compose between 6-10% of the annual peak demand. Typically, backup generators are not interconnected to the utility grid, but are isolated from the grid and operate only when the commercial supply is blacked out. Restructuring of the utility industry has opened up the possibility of capturing new benefits from distributed generation. These backup generators represent an under utilized resource that could serve functionally as distributed generation providing both spinning reserve and peaking power. If controls were added to make them dispatchable, backup generators could have substantial positive impacts, both for the owners of the backup generators and for the utility network in which they are located. Since they can be brought on line very quickly, the aggregated available capacity can serve as spinning reserve (available at full load within 10 minutes) without requiring that the backup generators to actually be in operation.


Demonstrate that existing backup generators can be cost-effectively aggregated and dispatched to provide spinning reserve capacity and peaking energy.


This project would aggregate these distributed generators by adding controls to make them immediately dispatchable from a single control point when required for reduction in peak demand on the grid. Recruit backup generator owners totaling 30 MW of backup capacity; procure and install the equipment needed to interconnect each participating generator and the system aggregator control room; enable communication from the control room to the New York power exchange; and analyze the results, including quantification of the economic and environment benefits.


This project offers improved system reliability, lower electricity costs, better utilization of the installed transmission and distribution systems, better system efficiency, as well as reduced distribution system investment, reduced transmission congestion, and lower cost ancillary services. There are also environmental benefits (CO2 reduced by 280,000 tons/year) resulting from displacement of conventional spinning reserve capacity which is traditionally provided by operating large fossil plants below their rated capacity. The capacity of the aggregated backup generators can be sold as spinning reserve even though they may not actually be in operation (and therefore neither consuming fuel/nor producing harmful emissions) since they can be dispatched and on line within 10 minutes.

Schedule and Status

Work on Phase 1, Tasks 1 through 4 began November 2000 and will be completed in December 2001. NYSERDA has also been awarded a contract by DOE/NREL to perform additional work which will build on the scope of the original contract between NYSERDA and Electrotek Concepts. This will include additional tasks such as the plans of the New York Independent System Operator (NYISO) to add "interruptible loads" to its daily auction; this means the need to have participating Backup Generator (BG) units on-line within one minute (to replace the utility supply). This will necessitate development and demonstration of a faster controller.

Last Updated: 07/01/2014