Zero Net Energy Library Project

The City of San Diego, in partnership with the Center for Sustainable Energy, California Energy Commission, Mazzetti Inc., M+NLB Construction Services, San Diego Green Building Council, and San Diego Gas & Electric completed a multiyear project to test, verify, and publicize the integration of energy efficiency, onsite renewable power and other demand-side resources to convert three public libraries to near zero-net energy buildings.

Energy-conservation measures implemented included light-emitting diode (LED) lighting, lighting controls, plug load management devices, heating, ventilation, and air conditioning controls, and whole-building automation platforms that measure demand trends to optimize equipment operations. 

The project also engaged and educated library staff, volunteers, and community members through interactive, in-library kiosks on zero-net energy and integrated demand side management strategies, sustainable energy, and associated environmental benefits, extending energy savings beyond the three project sites. 

To measure success, the project team conducted pre- and post-construction surveys of library staff and volunteers. The team also conducted nine months of post-retrofit measurement and verification with a three-month projection to estimate annual post-retrofit energy consumption due to COVID-19 shutdown of the libraries. 

The project results indicated that the energy-efficiency measures reduced electric consumption at the libraries from 13 to 30 percent. Photovoltaics were installed at each of the libraries independent of the grant. As a result, two of the libraries were able to achieve near zero-net energy due to combining the photovoltaics and energy-efficiency measures. The project demonstrated a blueprint to achieve near zero-net energy for other City of San Diego municipal buildings along with the benefits and challenges of retrofitting existing buildings.