The Pit 1 Powerhouse turned 100 today.

PG&E celebrates 100th anniversary of Pit 1 Powerhouse

One hundred years ago today, Friday, Sept. 30, a switch was flipped at Pacific Gas and Electric Company’s Pit 1 Powerhouse in eastern Shasta County, sending 220,000-volts of electricity to a substation 202 miles away in Vacaville. At the time, it was the longest and highest-voltage transmission power line in the world.

The powerhouse, power line and substation would help drive California’s economy by enabling clean and cost-effective power to travel great distances, and usher in more hydroelectric powerhouses and a network of long-distance transmission lines.

“Hydropower’s qualities as being carbon-free, reliable and affordable are as important now as ever,” said Jan Nimick, PG&E’s vice president of power generation. “We continue to leverage hydropower to meet peak customer demand periods for electricity like those we experienced in recent heat waves. Hydropower works when the sun isn’t shining and the wind isn’t blowing. It can be quickly dispatched to meet power needs for the grid and helps us fill in the gaps from renewable sources of power like wind and solar.”

Just as it did 100 years ago, PG&E held dual celebrations today at its Pit 1 Powerhouse in Fall River Mills and its Vaca-Dixon Substation. PG&E invited local PG&E employees, retirees, community dignitaries and school officials, and will presented a $50,000 grant to the Shasta County Office of Education to be designated to schools in Burney and Fall River Mills for STEM education. PG&E providing a $50,000 grant to Solano County Office of Education to support STEM education.

“We celebrate PG&E’s strong past and even stronger future,” said Joe Wilson, regional vice president for PG&E’s Sacramento & Sierra Region. “One hundred years ago, PG&E employees and the community gathered to watch the Pit 1 Powerhouse and Vaca-Dixon Substation come online and begin their long history of providing reliable energy to Northern California.”

PG&E also showcased latest technologies to promote a safer, more reliable and sustainable power grid at both locations.

History of the Pit 1 Powerhouse
Construction of PG&E’s Pit 1 Powerhouse along the Pit River began in 1919 amid various challenges. Not only was the project located in remote and rugged wilderness, but PG&E had many employees serving during World War I and the world was still in the thick of an influenza pandemic.

It took an average of 857 men employed each day for 26 consecutive months to build the powerhouse and a 2-mile tunnel and pipe system connecting Fall River to the powerhouse.

Large teams of mules were often used to haul equipment and materials, and shortly after construction began, a railroad was built to deliver the materials.

As the area was isolated, hundreds of workers stayed in camps and cabins with food prepared mostly from scratch by a team of bakers, butchers and cooks who served approximately 991,700 meals in those 26 months.

Pit 1’s location was chosen because the watershed drained by the Pit River and its subsidiary streams measured 4,900-square miles and the elevation difference from Fall River allowed for a 455-foot drop, generating high water pressure in the penstock (steeply angled pipe) to spin turbines at the powerhouse and generate 70 megawatts of electricity. At the time, it was the largest hydroelectric powerhouse in the United States and the second largest in the world.

PG&E’s hydroelectric powerhouses remain a main source of electricity to the region, with surplus power exported to the statewide electrical grid.

Sept. 30 also marks the 100th anniversary of PG&E’s Vaca-Dixon Substation, which also continues to operate. The Vaca-Dixon Substation also supports the network of transmission power lines and acts as one of the gateways for power serving the San Francisco Bay.

About PG&E
Pacific Gas and Electric Company, a subsidiary of PG&E Corporation (NYSE:PCG), is a combined natural gas and electric utility serving more than 16 million people across 70,000 square miles in Northern and Central California. For more information, visit and