Towards a Green Parliament

Later this summer, MPs will move into one of Europe's most environmentally friendly buildings. But is it worth £1m a head?

The last time a new edifice was constructed for Parliament, 150 years ago, the key aspect was beauty. When Charles Barry and Augustus Pugin spent nearly 25 years rebuilding the Palace of Westminster after the fire of 1834, they concentrated on producing a gorgeously-ornamented piece of Victorian Gothic, ablaze with brightly-coloured panelled ceilings, tiled floors, stained glass and murals.

But when architect Sir Michael Hopkins got together during the 1990s with engineers Ove Arup to design Westminster's long-awaited overspill offices, Portcullis House across the road, they had a more complex agenda.

Not that the new £230m building, due for completion in July, is not beautiful. The solid-looking block, echoing in its exterior shape Norman Shaw's Old Scotland Yard building of 1890 on its other side, has a stunning interior courtyard whose clear glass roof is supported by slender interlacing wooden beams. The offices for the 210 MPs, who will start occupying it in September, are spacious and airy, all pale oak and precast concrete polished to the smoothness of marble.

But in a new century preoccupied with problems the Victorians never knew, such as global warming and depletion of the ozone layer, the design priority for Portcullis House has not been charm of appearance, but to leave as little impact on the planet as possible.

It looks like succeeding. The fact that the MPs' offices are costing more than £1m each has been well publicised, but less attention has been paid to the fact that this is probably the most environmentally-benign block in Britain, if not Europe.

The secret is the integration of its engineering with its architecture: the building has been designed from the outset to save energy in every way, and make maximum use of sunlight, fresh air and even the water in the aquifer deep under London. This is a building without radiators or air-conditioning units.

The facade, though sealed with triple-glazed windows which are bombproof as well as soundproof, is a "living wall" which collects the sun's heat via dark blinds and transmits it to air circulating under the floor for heating. (Daylight in the rooms is preserved by "lightshelves", angled reflectors at the window tops.)

Summer cooling is provided by water from two boreholes sunk 150 metres through the chalk below the building, which cools down the circulating air. This avoids any refrigeration system involving ozone-depleting CFCs or their successor chemicals, some of which are still environmentally damaging. (The water is further used for the building's lavatories)

All the way through, energy is recovered and re-used, culminating in remaining heat being extracted in the roof turrets - the things that look like chimneys - as the heating air, which only circulates once, is expelled to the outside. Even the fabric of the building itself is used to store heat.

The result, Over Arup says, is a building that will use only between a quarter and third as much energy as a similar block of conventional design, with the energy saved equivalent to about 2,600 tonnes of carbon dioxide anually.

MPs may thus sit in the splendour of Portcullis House and think they are doing some good and helping to make the world a better place, for once, in this case, with justification.