Green giant

Success stories don't come much bigger than this. Clifford Chance's new headquarters is 30 storeys high, with a floor area of 100,000 m² and an expected population of 10,000 people. But it's not its size that makes it special – it is its green credentials.

This shiny glass and steel office is the largest building in Europe to receive an "excellent" rating for environmental performance from research organisation BRE. It is also the first building at Canary Wharf to be awarded this accolade – and it is in the forefront of its developer's drive to champion energy conservation in construction. The measures pioneered on this project will soon be used on every new building on the estate.

"Tenants are coming to us with a stronger environmental policy than they used to," says Robert Deatker, project executive for building services at Canary Wharf Group. "I'm sure this is because they have to report their carbon dioxide emissions in their annual report."

Canary Wharf Group uses BRE's BREEAM system to rate its buildings. BREEAM – BRE Environmental Assessment Method – measures energy use, water consumption, building materials, land use, ecology transport, health and well-being, pollution and building management. It rates buildings' performance as pass, good, very good or excellent.

The estate's earlier buildings only managed "pass" or "good" ratings because many of them relied on basic measures to cut energy consumption. The second phase of buildings, such as the HSBC tower, improved energy performance by recovering waste heat from the air-conditioning exhaust air, but, says Deatker, "There's nothing clever about that."

The law firm's office – 10 Upper Bank Street – was to be handed over as a "turnkey" development, ready for the tenant to move into. Because Canary Wharf could choose items such as light fittings, Deatker decided to aim for the "excellent" rating.

The main improvement Deatker has introduced is a more efficient and extensive heat recovery system. Called condenser water heat recovery, it takes waste heat from computer suites and other areas where large amounts of heat are generated. In many of the other buildings this heat is wasted – this is graphically illustrated by the plume of water vapour rising into the sky above One Canada Square on cold days. The condenser water heat recovery system uses that heat to temper and humidify the air for other areas of the building.

The energy savings are impressive because the Clifford Chance building needs so much air for ventilation – 123 m³/s. Deatker says warming this air with recovered heat equates to 4.2 million MW/hr of saved energy a year. "The performance is so good we were able to omit a substation," he says.

Other energy-saving innovations at 10 Upper Bank Street include high-performance glazing that limits solar gain in the summer, reducing the amount of energy needed to cool the building.

My favourite is 33 Canada Square, the first Citigroup building by Foster. It was very different and challenged us immensely. It gave me many a sleepless night

Robert Deatker, project executive for building services, Canary Wharf Group

There are also sophisticated electronic controls for all building services, including a fully programmable lighting system that helps minimise energy consumption.

A new wind blowing
Deatker's next ambition will be to achieve the "excellent" badge for all Canary Wharf Group's future buildings. It is a task made more difficult by the nature of the tenants' businesses. Many are financial institutions or law firms that demand highly serviced offices. Some of them host data centres and dealer rooms packed with rows of computer screens. Nonetheless, Deatker is optimistic – and he has other green ideas up his sleeve.

At Clifford Chance, he has introduced measures that mean the building consumes very little energy; his next move is to ensure that the energy consumed is from an environment-friendly source. He will explore this issue in the next major phase of work: "For the North Quay and Riverside South developments (see pages 72-74), we will have to address renewable energy sources."

He is not convinced that photovoltaic panels and wind turbines are the solution. "What we don't want is tokenism by sticking a couple of PV panels on the front of a building," he says.

Another idea was to use the water in the docks themselves to cool buildings – but this has been ruled out because it would raise the dock water temperature, which could kill fish living in them and may lead to the creation of algal blooms, which can be toxic.

Deatker's idea is a little more radical – he thinks Canary Wharf and its tenants could collaborate to sponsor offshore wind farms. "Canary Wharf wants to be able to offer a long-term sustainable energy solution to its tenants," he says, and he is already talking to utility companies about the viability of his idea. He is also carrying out an engineering analysis to see what the future energy strategy should be for Canary Wharf, given tenants' requirements.