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Sonoma County Renewable Portfolio Design

Analysis of existing demand and opportunities for efficiency and renewable energy insertion

Renewable Portfolio Design

The development and analysis of a renewable energy portfolio (suite of projects) is underway for Sonoma County. The initial development of this renewable portfolio is based upon information assembled for the Sonoma County Community Climate Action Plan Energy Element.

Data Collection

Demand Side Data

Acquiring energy use history for an entire California county creates an opportunity to look simultaneously at the “macro” regional energy demand curve and the energy price at the meter of each individual customer, based on the demand history at each meter. The research team obtained customer use data for 250,000 meters in the county through a formal request to PG&E by all of Sonoma County’s governments. These data give the research team the tools needed to do the following:

  • Create demand profiles by region to determine how to flatten out peak usage by deploying demand response technologies where we can get the biggest bang for the efficiency buck.
  • Locate renewable energy supply as close as possible to areas of high demand to minimize transmission distances, thereby lowering the energy and financial costs of transmission.
  • Identify opportunities for siting co-generation facilities in areas of high energy use to capture and reuse waste heat. There are often other renewable energy assets associated with these sites, such as large rooftops.


Above is a chart of electricity demand in the County for 2008. Time of day (hours) is plotted on the vertical axis vs. calendar day on the horizontal axis, and demand in kilowatt-hours (kWh) is plotted in colors (blue--150,000 to red--600,000). The red, orange, and yellow hot spots in the late afternoons reflect the overlap between commercial and residential use. In May through September, hot spots are caused by air conditioning, and in November and December they are caused by heating demands. Energy supply must be designed for the peak demand, which occurs relatively infrequently. Lowering these peaks with energy efficiency or demand control measures would significantly lower the cost of the renewable energy infrastructure required to meet the load.

Supply Side Data

The research team has also obtained other forms of local and state data from sources including the CEC, Sonoma County, SCWA, and city governments. For example:

  • Land use and zoning designations — To identify barriers and opportunities for developing renewables
  • Existing energy-related infrastructure — For example, utility rights of way, substation locations, existing geothermal wells, landfill locations, natural gas pipeline routes, reservoirs, existing generation facilities, etc.
  • Other geographic features or energy-related studies — For example, hydrological feature maps, studies regarding renewable energy or efficiency potential, wind generation potential, etc.

Initial Design Concepts

The research team is reviewing the many layers of data to identify locations within the County for strategic siting of renewable energy generation, demand reduction, and efficiency projects. For instance, the team is identifying co-locations of:

  • institutions that need a reliable supply of power (like hospitals, schools, and some industry)
  • large electricity consumers (like industrial parks and municipal pumping stations)
  • energy infrastructure (natural gas lines, electrical transmission lines, aqueducts)
  • public land parcels
  • large roof areas for solar arrays to serve local electricity demand
  • geothermal wells and resource areas
  • gas stations (for siting electric car chargers)
  • opportunities for beneficial use of waste heat to warm neighborhoods or generate electricity (co-generation)

Neighborhoods provide opportunities for "micro-grids" and efficiency islands when these features are combined in creative ways, as illustrated in the sample image below.

Example RE portfolio site