Sonoma Solar Water Heaters Hold the Key to California's Energy Independence

ByMark Anderson

Sonoma County should effectively subsidize the installation of solar water heaters to promote energy efficiency and reduce the region’s carbon footprint.

The County of Sonoma’s effort to implement a community choice aggregation program that would limit the amount of fossil fuels released onto the power grid can be bolstered by a plan that encourages the utilization of sustainable, renewable energy projects. The first step in Sonoma’s community choice aggregation effort should be to limit energy use and increase efficiency — an objective that can be solved in part via solar water heating.  A program of installing solar water heaters will be a pragmatic response to the rhetorical demands of Sonoma County’s call for energy independence.

The thermosphony solar water heater is the most cost-effective way of harnessing energy from the sun and is a proven method to reduce the user’s carbon footprint while decreasing the amount of water consumed. First developed in the early 1900s, the system’s popularity peaked in the early 1980s following the Carter era oil crisis. The system lost its appeal as oil prices fell in the late 1980s and early 1990s; but recently solar water heaters have made a comeback. The use of solar water is very popular in China, Germany, and Australia; Israel and Spain have even mandated that all new buildings install the system.


California residents are already able to receive rebates for up to 30 percent of the upfront cost of solar water heaters; a power purchasing agreement could close the gap needed to fund the system.  For local governments throughout California, lack of funding is a bitter reality. One plan is to formulate a public-private partnership in which a local bank or investor would participate in the process.  Private sources sponsor many power-purchasing agreements throughout the country with a governmental body sponsoring the risk. For example, through Honeywell’s ESCO project, hundreds of publicly owned buildings throughout the country have undergone energy efficiency retrofits that have cost taxpayers nothing and saved schools and military bases millions of dollars in energy costs.

The widespread installation of solar water heaters will contribute to major decreases in emissions levels for Sonoma County.  Installation of solar water heaters on a national scale could reduce carbon dioxide emissions up to 3 percent from current levels. Such an impact will fit positively in Sonoma County’s agenda to dramatically improve its carbon footprint.

Such an impact will fit positively in Sonoma County’s agenda to dramatically improve its carbon footprint.

Next Steps

Affordable solar water heaters can be made available to citizens of Sonoma County. The greatest obstacle in the way of effective implementation of renewable energy systems is the risk that is imposed by users. Sonoma County’s government can sponsor the risk for homeowners to convert to energy efficient water heaters, enabling funding opportunities from private independent sources and give users access clean and efficient energy. Essentially, the County should create the framework for a public-private partnership that fosters energy efficiency retrofits. This partnership should be in the form of a power purchasing agreement. Such a contract would exist between the user and financer where the financer pays for the initial costs of a solar water heater and the user pays off the financer with interest over time. Given that many solar water heater users find that their system pays for itself between three and five years, cost efficiencies, combined with a low-interest loan created by the power purchasing agreement, should take about the same amount of time to pay off.  Public subsidies available on top of a relatively short buy-back period will ensure that the purchasing power agreement can be paid off quickly.