Water Conservation
and Management

Estimated gallons of water saved by customers who adopted energy efficient measures that also
save water

California is in the midst of one of the most severe droughts in the past 100 years, creating increased demand for water by a wide range of stakeholders across the state. PG&E is taking numerous steps to conserve water in our operations and protect the watersheds where we operate. We also continue to offer incentives to help customers conserve water.

Our Approach

We formed an internal task force to coordinate our drought response and provide governance and oversight across PG&E. We are going above and beyond our regular efforts to conserve water in our facilities. We are also increasing outreach to educate employees on reducing water use at work and at home, and helping customers conserve water through energy efficiency.

PG&E’s website features drought resources, including tips, tools and information to help customers save water, energy and money.

PG&E’s water conservation and management efforts span a range of areas:

  • Reducing water consumption at PG&E offices and service yards
  • Using air for cooling at our generation facilities (versus more water-intensive once-through cooling)
  • Developing plans to manage the potential future impacts of climate change on our hydroelectric system
  • Helping customers reduce their water use
  • Working with suppliers to reduce their water use

Water Use at Diablo Canyon

While PG&E has no power plants that use freshwater for cooling, Diablo Canyon Power Plant uses saltwater from the Pacific Ocean for once-through cooling. The 2,240 MW nuclear power plant has a maximum discharge of 2.5 billion gallons per day, set by the facility’s Clean Water Act permit. PG&E closely monitors the marine environment at the plant by conducting regular studies and sampling required under the plant’s Clean Water Act permit.

In May 2014, U.S. EPA issued federal regulations under Section 316(b) of the Clean Water Act to minimize adverse environmental impacts from facilities that use once-through cooling. The rule allows Diablo Canyon to continue to be regulated under California’s once-through cooling policy adopted in 2010, which is considered to be at least as stringent as the new federal regulations. Under state policy, nuclear facilities may receive a variance from the compliance requirements if they meet certain cost and technical feasibility criteria. The State Water Resources Control Board is expected to decide whether to grant PG&E a variance in 2015.

In lieu of consuming local freshwater, PG&E uses seawater reverse osmosis to generate the majority of freshwater for Diablo Canyon to support the internal operations of the facility.

Dry Cooled Conventional Sources

PG&E relies on air for cooling at its three natural gas power plants. Humboldt Bay Generating Station is cooled with air radiators using a closed loop liquid coolant and requires minimal water use. We use an air-cooled condenser at the Gateway Generating Station, which uses approximately 97 percent less water and discharges 98 percent less wastewater than a traditional once-through cooled plant. The similarly designed Colusa Generating Station also uses dry cooling and a zero liquid discharge system that recycles wastewater. PG&E uses some freshwater for the internal operations at the plants, but these are largely closed loop systems that minimize the amount of water consumed.

Hydroelectric Operations

(Photo by James Green)
Helms Pumped Storage operates between two reservoirs in the Sierra Mountains.

PG&E owns and operates the nation’s largest investor-owned hydroelectric system. Our hydroelectric power plants are largely non-consumptive, meaning that after water passes through turbines to produce electricity, it is returned to the river.

PG&E also uses water for energy storage to help balance daily variations in electric demand at the 1,212 MW Helms Pumped Storage Project. Located more than 1,000 feet inside a solid granite mountain, the non-consumptive facility alternately draws water from an upper reservoir to produce electricity when demand is high and pumps it back when demand is low for reuse during the next high-demand period.

Water Conservation in Our Facilities

PG&E’s offices and service centers rely on water for restrooms, kitchens, mechanical system cooling, vehicle washing and landscape irrigation. PG&E set a five-year goal to reduce water usage in offices and service yards by 20 percent by the end of 2014, with 2009 as the baseline year.

(Photo by the Center for Irrigation Technology)
PG&E’s program to encourage agricultural customers to improve pumping and irrigation systems has saved millions of gallons of water.

We fell short of our annual water reduction target in 2013 due to irrigation needs during statewide drought conditions. However, we achieved an 18.7 percent reduction toward our overall five-year goal of 20 percent by 2014. Given the importance of this area, we have stepped up our efforts to conserve water in our facilities and further engage our employees.

Helping Customers Reduce Water Use

PG&E’s energy efficiency programs also help customers reduce their water use. We analyzed a dozen of the more common water-saving technologies promoted through our energy efficiency incentives in 2013 and estimated the savings to be approximately 1.9 billion gallons of water per year, which is enough water to fill nearly 2,800 Olympic-sized swimming pools.

About 67 percent of these savings (1.3 billion gallons) were achieved by helping agricultural customers switch from high pressure irrigation systems to more efficient methods. The other 33 percent (0.6 billion gallons) were achieved through rebates that provide incentives for customers to purchase energy- and water-saving items such as clothes washers, commercial laundry equipment, faucet aerators and low-flow showerheads.

Water Conservation Showcase

Every year for more than a decade, PG&E has hosted a daylong conference to encourage and train developers, architects and other building professionals to become more energy efficient by conserving water.

2013 Milestones

During California’s drought, we are working closely with water agencies, regulatory agencies and other stakeholders to manage our hydroelectric resources in ways that maximize conservation. This includes conserving water in our reservoirs so hydropower will be available during peak demand periods of summer, and as much water as possible will be available to meet environmental, agricultural and drinking-water needs.

Other initiatives included:

  • Continued reducing water use in PG&E’s offices and service centers. We took various water-saving measures, including installing water efficient urinals, toilets, faucets and showerheads; using irrigation smart meters and real time sub meters; and planting drought-tolerant landscaping.
  • Continued to operate air-cooled plants. Colusa, Gateway and Humboldt Generating Stations continued to employ state-of-the-art dry-cooling technologies in their operations to conserve freshwater.
  • Assisted agricultural customers. We helped agricultural customers manage their need for increased pumping given the drought. We partnered with the California Farm Bureau Federation, the Agricultural Energy Consumers Association and the South San Joaquin Irrigation District on a request to the CPUC to delay the ordered termination of two agriculture rates until 2015. The CPUC approved the request, which effectively allows farmers and ranchers more flexibility in their pumping operations. We are also creating enhanced energy efficiency incentives for agricultural customers.
  • Enhanced water management practices for hydrostatic testing. Through our Pipeline Safety Enhancement Plan, PG&E has conducted hydrostatic testing on hundreds of miles of gas pipeline. In 2013, the program used over 6 million gallons of water. Through enhanced water management practices, PG&E reused or recycled nearly 90 percent of that water for other hydrostatic tests or agricultural irrigation.

Hydrographer Shares the Science of Snow

PG&E is one of several organizations that collect snow survey data in California. In fact, PG&E established one of the first permanent snow courses, or measuring stations, in California in 1910. The adventurous staff that perform these snow surveys are called hydrographers. They work in teams and often fly in by helicopter, drive in by Sno-Cat or snowshoe in, and make measurements over a wide expanse of the watershed.

(Photo courtesy of Mark Crosse, The Fresno Bee)

Measuring Progress

The following table presents PG&E’s water use statistics.

Water Use Statistics
  2011 2012 2013
Water Withdrawal (Saltwater and Freshwater) (thousand gallons)
Once-Through Cooling (Saltwater)
Diablo Canyon Power Plant1 863,753,000 833,390,000 845,609,000
Domestic and Process Water (Freshwater)
Diablo Canyon Power Plant 145,546 149,705 152,724
Freshwater2 13,410 21,100 21,400
Seawater Reverse Osmosis Product Water 132,136 128,605 131,324
Humboldt Bay Generating Station1 231 131 193
Gateway Generating Station1 20,339 20,012 14,893
Colusa Generating Station1 2,810 4,086 32,3213
Facilities (Freshwater)
Offices and Service Yards4 121,400 122,473 127,208
Permitted Water Systems5 55,324 64,044 66,912
Hydrostatic Testing (Freshwater)
Total Withdrawal 9,335 6,166
Reuse for Irrigation and Dust Control 1,798 4,034
Reuse for Other Tests 866 1,443
Wastewater Discharged (Saltwater and Freshwater) (thousand gallons)
Once-Through Cooling (Saltwater)6
Diablo Canyon Power Plant 863,753,000 833,390,000 845,609,000
Domestic and Process Water (Freshwater)
Diablo Canyon Power Plant
Permitted Discharge 134,345 135,401 141,469
Humboldt Bay Generating Station
Sanitary Sewer 86 59 73
Gateway Generating Station
Sanitary Sewer 10,155 9,262 8,603
Colusa Generating Station7
0 0 0
Hydrostatic Testing (Freshwater)
Total Discharge8 7,537 2,132
  • 1 Net operating capacity on December 31, 2013: Diablo Canyon: 2,240 MW; Humboldt Bay Generating Station: 163 MW; Gateway Generating Station: 580 MW; Colusa Generating Station: 657 MW.
  • 2 Freshwater sources are well water for back-up and emergency purposes.
  • 3 Increase due to a combination of operational conditions and improved tracking of water usage.
  • 4 This figure represents the water supplied to offices and service yards managed by the Utility’s Corporate Real Estate Strategy and Services department for the 12-month period from October to September. The 2012 usage has been adjusted from the prior report due to reconciliation of billing data. The data includes 125 sites in 2011, 135 sites in 2012 and 134 sites in 2013.
  • 5 PG&E monitors water usage at permitted, public water systems owned and operated by PG&E. These systems are metered in accordance with state regulations.
  • 6 These are estimated figures as PG&E only measures water withdrawal associated with once-through cooling.
  • 7 Colusa Generating Station uses a zero liquid discharge system. A septic system is used to manage sanitary waste.
  • 8 Of these totals, a portion of water was reused for other hydrostatic testing prior to being discharged.

In 2013, PG&E voluntarily responded to the CDP’s annual information request on water. This request was made on behalf of 530 investors around the world, representing $57 trillion in assets.

Looking Ahead

California’s reservoirs and snowpack remain critically low in 2014. Among other measures, a Governor’s Executive Order called on individuals and businesses to take specific actions to avoid wasting water, including limiting lawn watering and car washing. Emergency regulations for mandatory water conservation have since added to voluntary and mandatory water conservation actions by local water agencies.

We will continue to take action to conserve water in our reservoirs, address vegetation impacts on our gas and electric distribution systems, aggressively mitigate potential fire hazards and work with customers to help them reduce water use through our energy efficiency programs. We will also stay focused on reducing water usage in our facilities to achieve our goal of reducing water use by 20 percent from 2009 levels. We are also working with drought impacted communities offering bill payment assistance and volunteering at local food banks.

PG&E Employees Pledge to Take Action Against Drought

PG&E led a Water Wise Pledge Campaign to promote employee water use reduction—both at work and at home. We achieved our goal of having at least 10 percent of our workforce, or 2,200 employees, take the pledge to conserve water.

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