About the Business

Nuclear Operations



Total annual economic impact of PG&E’s Diablo Canyon Power Plant in San Luis Obispo and Northern Santa Barbara Counties

For more than 25 years, Diablo Canyon Power Plant (Diablo Canyon) has played a vital role in meeting California’s energy needs, serving as a key source of safe, reliable and virtually carbon-free energy. The plant generates about 20 percent of the electricity PG&E provides to its customers. In addition, as a major employer and purchaser of goods and services, Diablo Canyon and the employees who work there are an integral part of the San Luis Obispo community and the Central Coast economy.

Commitment to Seismic Safety

PG&E remains focused on ensuring that Diablo Canyon continues, and improves upon, its strong record of safe operations. In the wake of the 2011 Fukushima nuclear accident in Japan, this includes a focus on assuring that the facility can continue to operate safely based on the assessment of new information about the local natural hazards, including earthquakes and tsunamis.

PG&E employs a seismic department staffed with experts. Shortly after commercial operations began (and as part of the licenses to operate Diablo Canyon), PG&E implemented and committed to maintain a Long Term Seismic Program. Under this program, a team of geoscientists continually study local geologic features and regional and global seismic events and apply new information to ensure that Diablo Canyon is seismically safe.

An important component of the program is PG&E’s work with the U.S. Geological Survey (USGS) to update the understanding of earthquake hazards along the Central Coast and throughout PG&E’s service area. In 2008, for example, this program identified a previously undiscovered fault known as the Shoreline fault zone.

PG&E evaluated whether that fault zone presented a safety risk to the plant and submitted its findings to the Nuclear Regulatory Commission (NRC). The evaluation confirmed the plant has an adequate safety margin to withstand ground motions associated with the Shoreline fault zone. Also, in response to concerns expressed by customers and neighbors in the community about the seismic safety characteristics of Diablo Canyon following the Fukushima nuclear accident, in 2011 PG&E made a formal request to the NRC to delay the final issuance of the plant’s license renewal until PG&E completes additional seismic studies utilizing advanced technologies.

In 2012 we completed the data acquisition of several advanced two- and three-dimensional onshore and three-dimensional low-energy offshore studies to further our knowledge of the region's complex geology. Data from the studies will be used to support PG&E’s ongoing work to assess and validate the seismic design of the plant. PG&E will also share the information collected with local, state and federal government agencies, so they can incorporate it into emergency preparedness plans and enhance public safety for the entire Central Coast of California. Independent experts who make up the Senior Seismic Hazard Analysis Committee process will also review and evaluate the data as part of a new, federally mandated update of the seismic risk for the power plant.

Continued Investment and Used Fuel Storage

Since operation began in 1985, PG&E has invested more than $1 billion on upgrades to Diablo Canyon. In 2012, this included a planned outage to refuel Unit 1 and perform scheduled testing and maintenance to maintain performance and reliability.

At the former nuclear unit at Humboldt Bay Power Plant, PG&E is in the process of decommissioning the facility. PG&E has completed large component removal as part of the first phase to remove radioactive components, piping and some structures. Subsequently, PG&E will remove all other equipment and decontaminate structures to permit building demolition and site restoration. A review from the NRC will follow site restoration.

At both Diablo Canyon and Humboldt Bay, PG&E uses on-site dry cask storage systems, approved and licensed by the NRC, to safely store used fuel. Diablo Canyon also safely and securely stores spent fuel in wet storage facilities. These on-site storage systems are used at nuclear power plants across the country and protect the used fuel against a range of threats, including severe weather, earthquakes and terrorism.

These two federally monitored on-site interim storage methods are safe and effective, and follow industry best standards. The ability to store spent fuel safely on-site, however, should not be a long-term alternative to the federal government assuming its responsibility to accept the fuel for permanent storage. To that end, PG&E will continue to advocate that the federal government meet its commitment and take charge of managing the nation’s spent fuel.

Additionally, PG&E actively manages the water used in the electricity generating process in accordance with the water discharge limit set by the facility’s Clean Water Act permit.

Supporting the Local Community

Diablo Canyon is a vital local economic engine and brings significant benefits to San Luis Obispo and Northern Santa Barbara Counties. PG&E is the largest private employer in the region and Diablo Canyon generates nearly $1 billion a year of economic activity by the funds it directly spends and the subsequent economic activity in the community from those investments. The plant is the largest property tax payer in San Luis Obispo County, which helps fund schools, public work projects, public safety, health and other vital services.

Additionally, our employees volunteer thousands of hours through educational, environmental and other community projects that benefit the region. They also contribute financially to nonprofit organizations through PG&E’s annual Employee Giving Campaign.

PG&E also has made local charitable contributions of nearly $1.1 million to more than 90 local nonprofits including school programs, senior centers and other vital community projects in the area.

Visitors can learn about the plant and a range of energy-related topics at our Energy Education Center and the Diablo Canyon website. Also, guided tours of Diablo Canyon provide an opportunity to speak directly with employees and learn how Diablo Canyon provides safe, clean, affordable and reliable electric service.