1021 O Street State Office Building

West Sacramento, Calif.

Excellence in Sustainability

Submitted By: Hensel Phelps

Region: ENR California

Owner: California Dept. of General Services

Lead Design Firm: HOK

General Contractor: Hensel Phelps

Civil Engineer: Morton and Pitalo

Structural Engineer: Crosby Group

MEP Engineer: FM Booth Mechanical

Electrical Subcontractor: Rosendin Electric

Associate Architect: Dreyfuss + Blackford


Energy conservation is a hallmark of this California State Office Building in Sacramento, one of the state’s first net-zero energy, net-zero carbon, all-electric government office facilities. The project team says the offices are a “benchmark” for state Dept. of General Services buildings, “setting a new standard for sustainability and flexibility for the state.” The 472,000-sq-ft, 10-story building is powered by 100% renewable energy through community solar agreements that result in 103% energy savings from the baseline. That approach provides utility cost savings to the state and gave the local Sacramento utility the customer commitment it needed to justify further solar farm developments and investments. A centralized building management system enables real-time analysis of building performance and fine-tuning of mechanical systems, including a low-friction air delivery system and water-to-water heat pump. The building has 100% LED lighting and individual task lights and electric vehicle-charging stations. It received LEED Platinum and CalGreen Tier 2 certifications. The outer facade overlays a precast/preglazed glass-fiber-reinforced concrete enclosure that enhances the building’s insulation and improves thermal performance, the project team says. The facade also responds to differing environmental conditions on each face.

1021 O Street State Office Building

Photo by Alan Karchmer

The project is noteworthy for other reasons. According to the contest entry, it was California’s first use of progressive design-build and saved the state 18 months, compared with traditional design-build. The fast-track project was to temporarily house the State Legislature, and the team had a firm end date to meet the Legislature’s schedule. The project was completed in June 2022, on schedule and below its budget. Missing the target date would have cost the state up to $130 million in delays. In 2022, the team also had to deal with wildfires and a downtown outbreak of civil unrest that included the deaths of six persons, according to published reports.

1021 O Street State Office Building

Facade enhances insulation, improves thermal performance and responds to differing environmental conditions on each face.
Photo by Alan Karchmer