Build Inc. is a commercial and residential developer based in San Francisco. Their aim has been to find extraordinary sites where the partnership’s collaborative creativity, imagination and expertise in the development and design process yields vibrant, exciting and beautiful projects: responsive to their neighborhoods, and in harmony with the surrounding urban fabric, environmentally responsible, and rewarding to their investors. (find more information at www.buildinc.biz)

Owners Loring Sagan and Lou Vasquez asked Borrego Solar to design and install a small pilot project on the company's office building in San Francisco. The project would allow Build Inc. to gain experience with the installation, operation, and maintenance of grid-tied photovoltaic systems. Furthermore the system would provide energy to the building and reduce the company’s dependence on power from PG&E. The company wanted a low cost, high performance solution that would yield a good return on investment.

Challenges

Build Inc. contacted Borrego Solar to discuss ways that renewable energy could be incorporated into some of their projects. Owner, Loring Sagan, had heard about rebates and tax credits available to California businesses investing in solar, and wanted to learn more. Solar power fit in well with the companies’ mission of environmentally responsible development.

Solution

Build Inc’s headquarters is a 3-story office building in Hayes Valley in San Francisco, CA. Working with a flat, built up roof with a composite top layer, Borrego Solar designed a system to yield optimum production in the limited space.

Sharp 185-watt solar modules were used due to their high efficiency. These modules were mounted at a 10 degree pitch. This pitch was chosen in order to optimize annual production and array power density. In addition a 10-degree pitch is sufficient to encourage water runoff, and therefore rain fall in the winter will be sufficient to clean the modules. This greatly reduced the maintenance costs associated with the system.

Borrego Solar designed and engineered a custom racking structure for this project. The racking system was attached to the building structural members in order to meet wind loading requirements. In addition the racking elevated the solar modules approximately 12" off the roof in order to promote backside air flow and increase array production.

Financial Benefits

Build Inc.’s grid-tied solar electric system will provide approximately 20% of the building’s energy requirements. Solar electric systems produce most of their electricity during peak times when power is most expensive. Therefore, by taking advantage of PG&E’s commercial time-of-use rate schedule Build Inc. is given a credit for energy produced at the peak rate. In total the company is saving approximately $2,000/year in utility bills.

Build Inc. received a rebate of $22,000 from the California Energy Commission for this project. In addition, the company was able to take advantage of numerous tax incentives. These include a 10% Federal tax credit, 7.5% California state tax credit, and accelerated Federal depreciation. By taking advantage of these government incentives Build Inc. was able to meet and exceed their return on investment requirements.