Water Conservation and Management
PG&E is working to protect and conserve water in our facilities and operations by implementing a variety of water conservation activities and best practices for managing storm-water. The importance of these measures has become even more acute recently, in light of climate change and its implications for water availability in California, both today and in the future.
Moving Toward Alternative Power Plant Cooling Systems
Most conventional power plants rely on water for steam production and cooling. The use of water in so-called "once-through" cooling systems can adversely affect aquatic organisms. Industrywide, once-through or other "wet" cooling technologies use ground water, municipal water or water from rivers and oceans to condense steam to water in the electricity generation process.
PG&E operates two power plants that use once-through cooling: Diablo Canyon and Humboldt Bay. Diablo Canyon is a 2,240 MW nuclear power plant with a maximum discharge limit of 2.5 billion gallons per day. Humboldt Bay, a 105 MW two-unit fossil fuel plant, has a maximum discharge limit of 76 million gallons per day. The water discharge limits are set in the facilities' permits.
As we build new conventional power plants, PG&E is implementing a variety of alternative cooling technologies to avoid the use of water. This includes utilizing "dry" cooling at the company's new Gateway and Colusa Generating Stations. PG&E is also repowering its Humboldt Bay plant with a new generation facility that will eliminate the need for once-through cooling.
Water Conservation in PG&E and Customer Facilities
In 2007, PG&E partnered with East Bay Municipal Utility District (EBMUD) to pilot a new water conservation program. Working together, we systematically identified PG&E's high-use facilities, conducted audits and tested strategies to reduce water use in EBMUD's service territory—maximizing the district's rebates. Water-saving strategies included installing a combination of dual-flush and low-flow toilets, touchless faucets and a state-of-the-art irrigation system that monitors and controls water use for landscaping. PG&E also implemented a new system to better monitor water usage at our facilities.
Recognizing the important link between energy and water usage, the CPUC approved a new water-energy pilot program in late 2007 that will allow PG&E and local water agencies to jointly offer water-saving incentives to customers.
Starting in July 2008, PG&E will partner with EBMUD, Santa Clara Valley Water District (SCVWD) and the Sonoma County Water Agency and their retailers to offer incentives to large commercial customers. PG&E will also work with SCVWD to install high-efficiency toilets in low-income homes and at least one water or wastewater utility to explore emerging technologies in communication systems that will result in water and energy savings.
Controlling storm-water pollution associated with various work sites and operations activities is an important requirement for PG&E. Until recently, PG&E used only traditional methods such as black silt fencing or placing tubular rolls of straw on slopes and around site perimeters and storm drain inlets. To meet our compliance obligations in a more sustainable way, PG&E now uses an innovative reusable and recyclable fencing, which improves safety and retains twice the sediment at half the cost.
PG&E is also coupling our storm-water best management practices with efforts to battle the spread of sudden oak death and noxious weeds, which threaten native plants and the habitat they provide. A cross-departmental team developed a portable wash station for cleaning tires, vehicle undercarriages, equipment, tools and materials on or near access roads. The portable stations are designed as a closed loop system, which saves water. In 2007, we successfully used five of these wash stations for a project in Lakeville-Sonoma that traversed through several sensitive areas and wineries.