Green watch: March 2009

Maurice Davies, Issue 109/3, p9, March 2009
The California Academy of Sciences (CAS) claims it is "officially the greenest museum in the world". Its new building is the only museum to achieve a "platinum" rating under LEED, the main US rating scheme for green buildings.

While many small museums are probably far greener, CAS has some impressive features for an internationally significant museum. It recycles nearly 80 per cent of its waste, is insulated with recycled jeans and features sustainability as a theme in its public programmes.

The defining design motif is a 2.5-acre living roof planted with 1.7 million native Californian plants. The roof absorbs rainfall, diverting millions of gallons of water from the sewers. Skylights allow natural light into the galleries, which are also naturally ventilated.

In warm weather, louvres and skylights automatically open and close to allow cool air to enter the building near the ground and warm air to escape higher up. In cooler weather, ventilation is provided only high up, to minimise draughts, and heating is provided from tubes set in the massive floor slab.

The result is that the new CAS building is expected to use about a third less energy than a typical building of comparable size.

But the new building has a larger floor area than the one it replaces and annual energy consumption is expected to be only about 15 per cent less than in the old building - and 60,000 expensive, high-efficiency photovoltaic cells will generate a mere 5 per cent of energy requirements.

CAS's building is world leading, but it demonstrates the difficulties museums face if they hope to significantly reduce energy consumption and grow in size.

Maurice Davies is the deputy director of the Museums Association