California Academy of Sciences.)It took almost 10 years and $500 million to plan and complete, but the California Academy of Sciences’ new ultra-green museum in San Francisco’s Golden Gate Park is ready to open. The public will be able to get its first glimpse of the building — dubbed a “masterpiece in sustainable architecture” — starting at 9:30 a.m.  Saturday, Sept. 27.

So what’s so green about the new facility? Almost everything, from basement to rooftop. The building is designed to earn the top level — platinum — of LEED certification for green construction. A “living roof” will boost insulation and prevent 2 million gallons of stormwater runoff each year. A canopy of solar cells will generate 213,000 kilowatts of electricity each year, enough to meet 10 percent of the museum’s needs. And radiant-floor heating and denim insulation will keep temperatures comfortable while minimizing energy consumption.

Even the stuff that didn’t go into the new museum was as sustainable as possible. For example, 90 percent of all the demolition materials left over were recycled, and 32,000 tons of sand dug up to clear way for the foundation were used for dune restoration efforts in other areas in San Francisco.

During the grand opening weekend, the museum will offer biodegradable cups and free water stations to eliminate the need for plastic water bottles. And special booths set up to mark the occasion will be poewred with biodiesel. Recycling and composting bins will also be available, with volunteers on hand to help visitors dispose of items properly.

Even the food for the opening-weekend party was chosen to be eco-friendly, with fair-trade coffee, organic and vegetarian foods and biodegradable packaging.

And here’s another plus: if you arrive on foot or by bike or public transportation, you’ll get $3 off the price of a general admission ticket. Don’t worry about finding a place to stow your bicycle, either: the San Francisco Bike Coalition is making sure there’ll be enough parking for 2,500 bikes.

The Cal Academy’s Website features all sorts of photos, videos and other information about the planning and construction process of the museum. Be sure to check it out, whether you can actually visit or not: it’s pretty impressive.