By Melissa Reynolds

Think of a museum and you think of what is old. Think of the California Academy of Sciences museum, though, and you think of what is green.

The California Academy of Sciences in San Francisco can boast the title of being the greenest museum in the world with the highest LEED certification - Platinum - given by the U.S. Green Building Council. With a total score of 54 points, it is the world's most sustainable museum building. To obtain a Platinum rating, a building must garner at least 52 points on sustainable site, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, and innovation and design process.

Ten years in the making, this 410,000 square foot building cost nearly $500 million to build. Founded in 1853 as the first scientific institution in the West, the California Academy of Sciences is the only institution in the world to house a planetarium, aquarium, natural history museum and research program under one roof. The new building, which replaces the old one damaged in the 1989 earthquake, is as sustainable as possible through energy efficiency, water usage, and recycled materials.

When it opened its doors in September, 2008, the museum could boast an interior that is insulated in nontoxic, second-hand blue jeans material with a 2.5 acre living roof, completely integrated into the surrounding landscape with native wildflowers and thousands of live species of flora and fauna, attracting local wildlife to live in it. The building itself holds 20 million specimens.

The museum was designed by Pritzker Prize-winning architect, Renzo Piano, with the goal of transparency, leaving the image of dark, dusty museums behind. It consists of walls made entirely of glass, allowing visitors to see from one end of the building to the other. The living roof helps to moderate the temperature of the building, keeping it about 10 degrees cooler than a tar roof would. Skylights can be opened to allow for air flow.

All of these features use between 30 to 35% less energy than what is required under standard building code, as well as generating some of the building's own energy, conserving water and creating new habitat for local wildlife. Some of the museum's other green features are:

• Radiant floor heating reduces energy needs by up to 10%.
• High performance glass used throughout the building reduces standard levels of heat absorption and decreases the cooling load.
• At least 90% of regularly occupied spaces have access to daylight and outside views, reducing energy use and heat gain from electric lighting.
• The skylights are strategically placed to allow natural sunlight to reach the living rainforest and coral reef.
• Sensor faucets in the bathrooms will charge themselves through an internal turbine that generates power to charge the battery pack.
• A solar canopy around the perimeter of the roof contains 60,000 photovoltaic cells that supply almost 213,000 KWh of clean energy per year and prevent the release of more than 405,000 pounds of greenhouse gas emissions annually.
• The living roof absorbs rainwater and therefore prevents up to 3.6 million gallons of runoff from carrying pollutants into the ecosystem each year.
• Over 90% of demolition waste from the old building was recycled.
• Approximately 1.7 million plants grow on the living roof.
• Local materials and products manufactured within 500 miles of the museum account for at least 20% of building materials, reducing transportation costs.

Along with all of these features, the museum is chock full of a variety of exhibits. Visit the African Hall or the California Coast or check out Climate Change in California. Stop by the Philippine Coral Reef or the four-storey Rainforests of the World or take a peek at the swamp tank. Even the museum's two restaurants offer organic, sustainable food.

The biggest green exhibit though? The museum itself, of course. It sits as an example of what the future can truly hold when it comes to green buildings. It is one of ten pilot green building projects of the San Francisco Department of Environment.

For much more on the museum's green features, exhibits and information on how to visit, see www.calacademy.org.