Exelon Power, a unit of Exelon Corporation, recently completed upgrades to its Southeast Chicago Energy Project to provide increased stability to the regional power system in the event of a regional power failure.

The company upgraded the blackstart capabilities of its eight-unit, 350 MW plant to assist in restarting Exelon's larger nuclear units and other regional fossil plants in the event of a blackout similar to the one that affected the Northeast in August 2003.

A blackstart unit is defined as a generating unit that is able to start without an outside electricity supply or demonstrated ability of a base unit to remain operating, at reduced levels, when automatically disconnected from the energy grid. A blackstart plant is a power plant that includes one or more blackstart units.

The Southeast Chicago plant previously had Category Two blackstart capability, meaning the plant is self-sufficient to maintain essential functions when disconnected from the power grid, but requires power from the grid to restart, making it the second unit on line after a system outage.

"This blackstart upgrade allows us to ensure we have the required energy to be a reliable source of power should a major system blackout occur," said Mark Schiavoni, vice president of Exelon Power Operations.

"This is a state-of-the-art plant, equipped with some of the best technology available," said Schiavoni. "Upgrading the blackstart capabilities provides additional security to the ComEd system."

In order to upgrade the plant, a number of projects had to be completed. The plant required 6,000 kW of self-sufficient capacity to start the first fuel gas compressor and the first combustion turbine starting motor. To provide the required capacity, Exelon installed three, 2-MW diesel generators on site.

While blackstart units are not used often, they are an integral part of a system's contingency plans in the event of a system blackout. In the event of a blackout on the ComEd distribution system, Southeast Chicago Energy Project is able to begin generation and re-establish power onto the grid for larger plants that require offsite generation to begin operation.