To meet the goals of the Carbon Free Water Program, Sonoma Water has implemented several energy production, energy purchasing, energy efficiency, and sustainability projects. Below is the list of projects completed and currently underway.
Geothermal Resource AnalysisSonoma Water contracted Earth Systems Sciences LLC to conduct a study to characterize and analyze potential impacts of geothermal resources on hydrogeological resources in a small region of Sonoma Valley. Hovering questions preceding this study included: Is there significant geothermal heat generated in this region? Where is the main point source of heat in the study area? Does the magnitude of geothermal heat in this area have capacity for renewable power generation or for renewable heating of buildings or other commercial assets? Would utilizing this resource jeopardize the groundwater resource in these areas? Previous studies have been performed in this area in the 1970's and 1980's. But using a new approach to conduct modeling of subsurface geothermal resources, 'maximum likelihood' scenarios were generated to better describe the resource. This approach analyzed several factors (water chemistries, hydrologic properties, etc.) and determined that the south western quadrant of the study area showed signs of a sizable geothermal resource. In the study area, the historical maximum temperature readings were up to 185 degrees Fahrenheit at surface depth levels of 0.36 mi. Conclusions from the report analysis identify likely greater heat capacity of up to 230 degrees Fahrenheit at a depth greater than 0.8 mi. However there are some downsides to utilizing this resource in which Sonoma Water needs to consider. The first being that extraction may only be achieved at low flow rates (no more than 95 gal/hr). In other circumstances, a higher flow rate could cause negative impacts on entities previously utilizing the resource. Regardless of the model results, if geothermal extraction applications are pursued, a sophisticated monitoring program should be put in place to assure the impacts are detected quickly and remediated. |
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Photovoltaic SystemsSonoma Water has four photovoltaic systems that total to about 2 MW. The administration building has a 0.5 MW system that has panels flush on the roof and panels on a carport-like structure in the parking lot. The Airport Larkfield Wastewater Treatment Plant has a 0.5 MW fixed system that is ground mounted around the edge of one of the storage ponds. The Sonoma Valley Wastewater Treatment Plant has a 1.0 MW tracking system that is ground mounted in a field adjacent to a storage pond. Sonoma Water continues to investigate additional opportunities for solar power generation. The most recent ground mounted solar installment is that of Geyserville Treatment Plant, which has a 50 kW system. For more information, visit the Photovoltaic Systems page. |
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Floating Solar Photovoltaic SystemFrom September 2016 through March 2017, a pilot floating solar photovoltaic (PV) system was deployed on our Oceanview recycled water pond just north of Santa Rosa. This 40 foot by 40 foot floating system supported 40 PV panels. There were eight 2-ton piles of rock support cables attached to the aluminum support structure mounted on 30 polyethylene floats. Monitoring the floating PV system movement, flexibility, temperature, cable tension, and other variables during the pilot test, the floating PV pilot system weathered the wettest winter in Sonoma County recorded history. A successful pilot phase was a necessary step for Sonoma Water staff in order to determine the reliability and safety of a floating solar system vs. standalone or roof/carport solar system. The risks and costs include being an early adopter of new technology. However the benefits of floating solar range from low environmental impacts due to use of already disturbed land, greater efficiency due to the water's colling effect on the panels, and creation of a new energy generation revenue stream. Internal cost benefit analyses with different, potential contractual energy purchasing arrangements are taking place in order to begin a floating solar installation on a Sonoma Water reservoir. |
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Warm Springs Hydroelectric DamDue to the unique enabling legislation establishing Sonoma Water during the late 1940s, Sonoma Water was given authority to produce both water and power. At the time, most energy needs were met by hydropower resources. However Sonoma Water didn't exercise this power aspect until after the Warm Springs Dam was completed in 1984. A hydroelectric turbine was installed a few years later and has been producing electricity since then. This turbine is capable of generating 2.6 MW of power. Since energy production is influenced by the flow of water through the dam, power production is usually at about 1.3 MW. Annual energy production ranges from 9,000 MWh to 15,000 MWh depending on wet vs. dry years which determine the water releases through the turbine. Sonoma Water collaborates with the Army Corps of Engineers in the operation of the hydroelectric dam. Sonoma Water contractually buys and sells the energy generated to/from the Power and Water Resources Pooling Authority (PWRPA). As a PWRPA member, Sonoma Water is also given access to other cost-effective non-fossil fuel resources throughout the state. |
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Wind Turbine - Geyserville Sanitation ZoneIn 2013, a wind turbine was erected at the Geyserville Sanitation Zone wastewater treatment plant. The purpose of this partially grant funded project was to develop and test a model for a locally owned, cost-effective, renewable wind energy that would help Sonoma Water reach its greenhouse gas reduction goals. Unfortunately, this project didn't demonstrate the cost-effective aspect of expectations. An essential aspect of the Carbon Free Water program is cost-effectiveness. Nonetheless this provided a learning opportunity for the community and for Sonoma Water that wind energy in this area is not a viable renewable resource. Although our own wind generating capacity is small, Sonoma Water also contracts buys some wind power from Marin Clean Energy's Deep Green program. |
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Sonoma Clean PowerIn 2011, the Sonoma Water Board of Directors instructed Sonoma Water to investigate Community Choice Aggregation (CCA) while concurrently approving Sonoma Water’s Energy Policy. Community Choice Aggregation allows one or more cities and/or counties to form a service area that provides for the option to purchase power generation from local sources that has a different electricity mix than that of the original investor owned utility. Creating competition in the electricity generation market, by creating choice in energy providers, is good for the community and the environment by driving electricity rates to be most competitive while also having a choice in the types of energy you can purchase. Transmission, distribution, customer service and billing remain the same (delivered through the existing utility PG&E). Customers within this service area can opt out of participating in the CCA program and continue to receive their power generation services through the existing investor owned utility--although the starting generic rate for Sonoma Clean Power's Clean Start Program is both cheaper and less GHG intensive than that of PG&E's generic generation services. Learn more about Sonoma Clean Power. |
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Energy Efficiency ImprovementsIn the years following the purchase of the administration building, several projects have been implemented to reduce facility’s power requirements. Energy efficiency improvements included window film application, lighting retrofits, and LED installation. The window film saves energy by reducing the amount of heat transferred through the glass. It now requires less energy to regulate the internal climate of the facility. The film application has a lifetime of 15 years, and saves Sonoma Water approximately 30,000 kWh annually. Almost half of the lighting retrofits were paid for through the Association of Bay Area Governments. The savings were achieved by pairing higher quality tubes with more efficient ballasts and eliminating unnecessary lights (aka delamping) in areas of low usage. Each of the LED tubes used to replace fluorescent tubes have lifetime of 50,000 hours, which last twice as long as the best fluorescent tubes in the market today. |
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Hybrid, Plug-In Hybrid & Electric Vehicle FleetSonoma Water is currently electrifying our fleet with electric, plug-in hybrid, and hybrid vehicles. After achieving a carbon free energy supply, the Energy Strategic Plan was formed in order to create goals moving past our electricity supply. Since 2006, we've seen a reduction of GHGs by over 85% in our overall carbon footprint. This was entirely due to our electricity supply alone. Now, our largest source of GHGs is our transportation related fleet emissions. Sonoma Water purchased its first hybrid electric vehicle in 2006. As of 2017, Sonoma Water has 26 hybrid, plug-in hybrid and electric vehicles, which is 20% of the entire fleet of vehicles. Sonoma Water has joined a coalition of Bay Area local governments to pursue a grant through the Metropolitan Transportation Commission to fund fleet electric vehicles and charging infrastructure. Through the grant, Sonoma Water has received funding to supplement the purchase of five electric vehicles. In addition to charging stations already located at several Sonoma Water facilities, five charging stations are planned for installation by the end of the year through the grant. Learn more about our Electric Vehicle Fleet. |
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Recycling ProgramSonoma Water has an active recycling program at its administration building and its operations and maintenance center. Paper, plastics, glass, and aluminum cans are all recycled with the help of designated bins in the kitchens, copy rooms, conference rooms, and cubicles. Recycled paper is ordered for copiers and printers and recycled presentation materials are used whenever possible. Sonoma Water annually hosts an e-waste recycling event with the Computer Recycling Center. Large bins are provided on site for employees to contribute personal and office e-waste items. Sonoma Water also recycles ink cartridges from its printers. |
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Water Education & Conservation ProgramsSonoma Water has well-established water education and conservation programs. Over the last several years, the Mike Hauser Algebra Academy is hosted at Sonoma Water's administrative office. Here, Sonoma Water staff in the Energy Resources Group teach middle school students about the relationship between energy systems and environmental science. For more information about the Water Education program, click here. For more information about the Water Conservation Program, click here. |
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