Google has submitted informal plans to the Mountain View, Calif. Planning Department for a space-age structure that could be the greenest office building of all time.

The complex is five stories tall with undulating surfaces, and stretches like a pretzel around three courtyards.

Google's submission to the city shows that major effort went into picking a concept after studying dozens of alternatives, with plans stating that the structure would "create a benchmark for sustainability and help define new standards for construction."

There are no formal plans to construct this building, but in the plans, Google wants to go beyond LEED platinum??"the highest standard for a green building.

"This is a living building that has no carbon footprint," said Yvonne Farrell, a LEED-certified architect on Mountain View's Environmental Sustainability Task Force who studied the plans.

The design is based on a "courtyard circulation concept" which winds the hallways of the building around courtyards connecting to open spaces, including a park promenade between the building and the hotel-zoned site to the south.

The preliminary plan is the work of several architecture firms led by New York-based ShoP architects, which Google selected after a national search. The architects have created a physical model of the preliminary design, with people, cars and trees to show scale.

Some of the ideas behind the building, as described in the submitted plans, can sound fantastical. The plans claim, for example, that the building will "evolve" rather than degrade over time: "Typical building performance begins to degrade immediately upon completion of construction. In the Max Green model, monitoring and feedback allow the building to evolve as knowledge and information improve."

"That concept is how you are going to get the greenest building ever," Farrell said. "If you are around Googlers you know they are always striving. They do something, they get the feedback, they change it and they keep evolving. That's a very Googley concept. It's also a natural concept."

The site design, done by landscape architect Walter Hood, aspires to create a buffer between the Bay and the city's "industrial forest." So far, plans include an orchard just south of the building. The green slope beneath the building not only hides a 20-foot-tall parking garage, where cars are stacked tightly on top of each other, but rainwater runs off the slopes into vegetated "bio-swales." From there it feeds green roofs, gardens and planters as part of a "run-off conveyance system that slows, cleanses and celebrates runoff prior to discharge."

The plans mention a design with consideration of the sun's path for natural light and integrated next-generation solar panels, as well as consideration of prevailing winds for a natural ventilation system.

The package of information given to the planning department indicates that Google has ambitions beyond just building new offices. A map shows a mixed-use "urban center" and "transit node" surrounding the intersection of Shoreline Boulevard and Charleston Road (mixed-use developments usually involve housing on top of retail).