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Hydroelectric system

Discover how hydroelectricity provides safe and reliable power

Our hydroelectric system provides safe, reliable and clean energy. Its history dates back to the California Gold Rush. The system is also one of the largest investor-owned hydroelectric system in the nation.


Find out more facts about our hydroelectric system


Hydroelectricity is generated by the force of falling water. Usually, a series of dams and reservoirs collect this water. The water is then directed through large pipes. The pipes are called penstocks. Turbines use this water to spin generators to form electricity.


Our system is regulated by the Federal Energy Regulatory Commission (FERC) and by the California Public Utilities Commission (CPUC). The two commissions create environmental and operational requirements.


Following are additional facts about our system:


  • The system is built along 16 river basins. The basins stretch nearly 500 miles in our service area.
  • The system uses water from more than 100 reservoirs. Most of the reservoirs are located in the higher elevation of California's Sierra Nevada mountain range.
  • The system has 67 powerhouses.
  • The system produces roughly 3,900 megawatts (MW) of power.
  • The system can provide power for nearly four million homes.
  • We hold 26 FERC licenses. The FERC issues licenses for periods of 30 to 50 years.


Relax at public campgrounds and picnic areas around the hydroelectric reservoirs


Our hydroelectric system creates recreational areas for you and others to enjoy. Habitats for fish and wildlife are also established. Our Recreational Areas page enables you to view and reserve space at many of our reservoirs.

Learn more our recreational areas

Additional resources

Overview of current transmission projects

As part of our commitment to provide our customers with safe and reliable energy, PG&E is reinforcing the electric transmission system throughout the area we serve.


Read more about pipeline inspection, replacement, and safety initiatives

Gas Tools

PG&E is committed to the safety of the communities it serves and is working every day to enhance gas pipeline safety.