Location: San Rafael, California System Size: 588 kW Energy Output: 1,035,519 kWh per year Savings: $156,000 annually Results: CO2 emissions reduced by 1,442,281 pounds/year (equivalent to 1.7 million car miles/year) Success Story PDF Case Study PDF

	"Smart engineering offset 92% of our power bill, while respecting the wetlands environment adjacent to our facility. EI Solutions engineered a foundation that maximized our land use, and minimized the visual impact of the installation." - Mark Williams, Water District Manager

Las Gallinas Valley Sanitary District (LGVSD), located on the shores of San Pablo Bay just north of San Francisco, provides sewer services to over 32,000 residents of Marin County. On average, the District treats 3.56 million gallons of wastewater per day. The facility relies on power-hungry station pumps to send reclaimed water between the District's ponds and irrigation systems. LGVSD was interested in reducing its energy bills through the use of solar power.

The building site for the district's proposed solar array rested entirely on bay mud, an unstable and dynamic soil type common to shoreline regions in the Bay Area.

Because of the unstable soil conditions at the site, the EI Solutions engineering team needed to overcome several significant challenges when developing the solar power system. The team solved the problem by designing a custom grade-beam foundation that would minimize the potential problems of uneven settling of the soil beneath the array structure.

After developing an energy load profile for the District's Reclamation Pump Station, the team was able to determine the optimal system size to offset energy usage under local weather conditions. Finally, EI Solutions ran a number of utility rate scenarios to determine the best approach for maximizing the cost savings for LGVSD.

Thanks to the optimization efforts of EI Solutions, the system is expected to pay for itself in about 11 to 12 years, and will then provide approximately 20 additional years of "free" electrical power to the District. In the first year of operation alone, energy savings have been projected to exceed $156,000. "The fact that the system will eventually pay for itself made it an easy decision to go solar," says Megan Clark, board member of Las Gallinas Valley Sanitary District. "Plus we're reducing our impact on the atmosphere by receiving a full 92% of our power from clean solar energy."