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Blenheim-Gilboa
Pumped Storage Power Project

Blenhiem-Gilboa power plant photoThe Catskill Mountains are home to a special type of hydroelectric facility that serves as a giant energy-storage device—the Blenheim-Gilboa Pumped Storage Power Project. Nestled beneath 2,000-foot-tall Brown Mountain, this project generates more than one million kilowatts of electricity in peak demand periods by drawing water from Schoharie Creek and recycling it between two huge reservoirs.

Blenheim-Gilboa serves two vital functions. It saves money for New York consumers by providing low-cost electricity when they need it most. And it stores water for emergency power production. If necessary, this project can be up and running within two minutes. It can "pinch hit" if another plant or line suddenly goes out of service.

Here's how it works:

Each of the reservoirs—one atop Brown Mountain, the other at its foot—holds five billion gallons of water. When we're generating power, the water cascades down a concrete shaft that's five times taller than Niagara Falls. When we're storing water—usually at night or over the weekend—we reverse the process and pump the water back up the shaft for storage.

Aerial photo of Blenheim-Gilboa project facilitiesThe system allows us, literally, to "go with the flow"—to take advantage of the daily highs and lows in statewide electricity demand. In other words, we can generate power when we need it—generally in the late afternoon or early evening—and store the water that fuels the power when we don't need it. The electricity Blenheim-Gilboa uses to return water to its upper reservoir is inexpensive surplus power made available during low-demand periods. The cost of this power is cheaper than the electricity our project replaces the following day during peak-demand periods.

At Blenheim-Gilboa, we generate electricity at the powerhouse, a concrete structure that sits at the base of Brown Mountain on the banks of the lower reservoir. More than three-quarters of the facility is underground. When the lower reservoir is full, only five feet of the plant is visible above the water.

A $135-million four-year program to modernize and extend the life of the Blenheim-Gilboa project was completed in May 2010. As part of the four-year program, known as LEM (Life Extension and Modernization), one of project’s four turbine-generator units was taken out of service each fall for approximately eight months. Most of the unit’s mechanical and electrical components were replaced, with repairs made to virtually all other parts. With completion of the project, the four units have a generating capacity of 290 megawatts each, providing an overall project generating capacity of 1,160 megawatts.

The unspoiled beauty surrounding Blenheim-Gilboa is a pleasure for the many visitors—local residents and out-of-town tourists—who flock here for educational and recreational pursuits. Besides producing power, we operate a Visitors Center and help maintain adjacent attractions that generate good times as well.