Stok was engaged as the Energy Engineer by the County of San Diego to provide energy guidance for the Alpine Library - the first Zero Net Energy (ZNE) library certified under the Living Building Challenge.

At a Glance

County of San Diego
San Diego, CA
Government, Government & Education
13,500 SF
Ferguson Pape Baldwin Architects (Architect)Atelier Oncina (Architect)C.W. Driver Companies (General Contractor)
Living Building Challenge Zero EnergyLEED (Gold)
  • Whole-Building Energy Modeling
  • Zero Net Energy (ZNE) Feasibility Analysis

The Challenge

To collaborate closely with project team members and focus on client engagement to set the project up for ZNE success to meet client goals.

  • Prepare concept-modeling studies to identify the feasibility of the project to attain ZNE performance
  • Use these results to give the County the confidence to include ZNE in its Request for Proposal (RFP)
  • Assist the D-BE team to understand what its energy targets and strategies would need to be prior to design, as well as provide appropriate roof space for the PV and solar water heating systems
“There’s a difference between whole-building modeling and merely modeling for code-compliance. The whole-building energy modeling that Stok produced for the library shows how all the building’s components work together. And that’s how you reach ZNE in the smartest way.”

The Solution


Achieving the Living Building Challenge’s Zero Energy Certification, the new 13,500 SF Alpine Library, which opened in May 2016, is the first ZNE building built by a local government entity and the first library certified under the LBC program. Through thoughtful design, the library’s projected energy consumption was cut nearly in half, while construction costs stayed within the project’s $10 million budget. Our team’s guidance–with D-BE engagement and the client’s participation–led to a highly successful ZNE outcome for a beautiful community project.


In the final ZNE design, the project utilizes a solar panel system spanning its long south roof, angled to take advantage of the sun’s rays and expected to produce approximately 108,500 kWh per year. The library’s windows also take the sun’s position into consideration, as many of them are located on the north-facing side, which allows more natural light with less heat gain and glare. Our Measurement & Verification specialists managed the ZNE performance to ensure that the building systems were fully-commissioned and that the energy use data was accurate. After one full year of gathering data, we were able to verify that the building used less energy than it produced.


The library has received broad recognition for its sustainability performance, including the Sustainable Buildings LEED BD+C Honor Award, Sustainable Building Strategies’ ZNE Honor Award 2018, and Engineering News Record California’s Best Green Project 2016.


Photo Credit: International Living Future Institute

Project Leadership

Sandy Houck