In May 2009, five curious new wavy red-roofed bus shelters were constructed around San Francisco.  Their unorthodox design and interesting features have garnered recognition in many circles around the world, but very few have heard of the highly innovative and collaborative story behind this great green project.

According to Lundberg Design project manager Ryan Hughes, the biggest misconception about the project was that funding came entirely from the city of San Francisco. Instead, the city served as an enabler and beneficiary.  The SFMTA administers a long-term lease of the new bus shelter locations and advertising space, making the city a major beneficiary of the project, in terms of revenue and public infrastructure, but not the project’s financial investor.

Typically, bus shelters are financially viable because they are paired with large advertising boards, which outdoor advertising agencies negotiate rights for.  In late 2006, SFMTA issued an RFP for a 20-year lease of the bus shelters as the current contract was coming to a close.  The scope of the RFP included the design and construction of 1100-1500 new bus shelters, which called for integrated solar power or green features, and universal design/accessibility requirements.  In return the companies had exclusive rights to sell advertising with over fifty percent of the revenues to go back to the city. The RFP bidders (and ultimately, the contractor for these innovative new bus shelters) were all major outdoor advertising companies such as CBS/JC Decaux, ClearChannel Outdoor and CemUSA.

The three outdoor advertising companies each submitted between 10-15 new shelter designs, for a total of about 35 designs to be reviewed by various city agencies.  Clear Channel Outdoor chose to take a local route, hiring three San Francisco-based architecture firms to come up with designs. The boldest entry came from Olle Lundberg of Lundberg Design, who proposed a glowing wavy translucent roof as a signature feature. The shape was chosen to evoke both the multiple hills that make up San Francisco’s dramatic landscape, as well as the seismic waves triggered by occasional earthquakes. While unconventional, the strength of the strong design statement was undisputed and Clear Channel Outdoor was eventually rewarded the contract, exclusively using the Lundberg Design bus shelter.

Striking as the roof was, it served as more than just a dramatic design gesture.  There was a strong ecological justification behind the translucent red panels and the design and material selection process is a unique case study for innovation and material development. Lundberg Design searched high and low for a material appropriate to realize the curvy wave form. After considering glass and metal, they worked closely with 3form, a company known for their composite plastic materials, to adapt their Koda XT line, which includes 40% pre-consumer recycled plastic.  Koda is a highly durable polycarbonate material that can withstand the toughest exterior conditions: wind loads, moisture, thermal expansion in heat and contraction in cold. Working together, Lundberg Design and 3form modified the shape to take advantage of the strengths of the Koda material, adding additional thermo-formed curves to the originally flat end portion of the roof, to allow the ½” thick polycarbonate to span over four feet between the roof supports without sagging.

To raise the bar on ecological design performance, the designers wanted the roof to be a productive element itself.  The original design intention was for the roof to filter light but also harness light to create electricity.  Looking for the right photovoltaic product to integrate with 3form’s Koda line required a lot of collaboration.  Konarka Technology is a plastics company that makes a polymer based photovoltaic film, Power Plastic, which differs from typical photovoltaic cells that require silicon.  Konarka’s film consists of an organic dye printed on a clear plastic substrate to convert sunlight to electricity.  The inspirational design concept led to a pioneering project to encapsulate the Power Plastic modules into a colorful three dimensional and resilient structure. The challenge for Lundberg Design, 3form and Konarka was to develop a manufacturing process and assembly detail that would essentially assimilate the Konarka Power Plastic film to the curvy Koda XT roof structure without damaging the photovoltaics, and while maintaining a clean layout with even spacing of the photovoltaic film pieces.  After several rounds of testing lamination techniques and the development of custom molds, 3form devised the optimal assembly and process conditions to allow for successful lamination of the Konarka Power Plastic to the bold colors of the curvy Koda XT panels.

But what were the photovoltaics for?  The bus shelter roof was designed to produce enough electricity to do several things: 1) power an LED message board that gives NextBus updates, 2) power “Push-to-Talk” features which reads the NextBus information aloud for hearing impaired travelers, 3) operate a wi-fi router and 4)power  lights for advertising panels at night.  During the day, the roof generates more electricity than the NextBus sign,” Push-to-Talk” and wi-fi router requires and the shelters actually add energy to the grid.  Working with PG&E, the design team managed to connect the shelters directly to the grid and outfit a meter that runs in reverse.  At night, lighting the advertisements within the shelter consumes grid power, but the overall electricity usage is close to the amount generated by the panels.

In the seven months since five prototype bus shelters were installed, representatives from Konarka have tested the performance of the integrated solar panel, and found it to be performing slightly above expectation.  From the general assessment by Lundberg Design’s team, overall the shelters break even in terms of energy usage, generating enough power during to day to power all functions and sell energy back to the grid, and by night, spending about the same amount of energy that they put into the grid.

The San Francisco Bus Shelters are a great new model for green architecture, not just in terms of design, but in terms of technology and innovation, collaborative partnerships and a financial viability.   For many of us who believe in the value and practice of green principles in our design work, realizing green projects may require changes in our practice models. The standard architect-client relationship may not be enough, and creating innovative, high impact design projects may require engagement and collaboration with a broader spectrum of stakeholders. The success of the SFMTA Bus Shelters is a strong example not just of the design potential but of the partnership possibilities.

Elaine Uang works at Feldman Architecture.