Are fuel cells the future of heating?

The UK has been lagging behind the US, Japan and Germany in applying fuel cell technology to buildings. But with increasing legislation to cut carbon emissions, this is changing.

Two projects in London, SOM’s Arrowhead development on the Isle of Dogs for Ballymore, and three buildings for Aldgate Place in Whitechapel, by Wilkinson Eyre for Tishman Speyer, are set to derive up to 10% of their energy needs from fuel cells.

David Stillman of DSA Engineering, the services engineer behind both these office projects, reckons these will be followed by many more in the not-so-distant future. “Ten to 15 years from now, every single new building will be powered by fuel cells,” he says. “It’s the magic bullet — until we get fusion power going.”

This anticipated adoption of fuel cell technology to power buildings is partly due to the requirement under the London Plan for all new commercial buildings to cut carbon emissions by 20%, on top of fulfiling Part L requirements. Now developers have to take sustainability seriously to gain planning permission, making fuel cell technology’s ability to convert chemical energy to electrical energy all the more attractive, despite the greater capital expense.

Expensive solution

“Some technologies are more carbon-efficient than others,” says Stillman. “Fuel cells are two-and-a-half times more carbon-efficient than a conventional CHP plant. It’s the best solution. It’s also the most expensive solution.”

Contrarily, both the Arrowhead and Aldgate Place projects had to get special permission from the Greater London Authority to allow fuel cells to count towards carbon reduction — because fuel cells aren’t recognised as renewables in the London Plan.

For the 26-storey Arrowhead scheme, the design team had originally been keen to use the building’s dockside location at South Quay for ground water cooling, but this became less attractive because of Environment Agency restrictions on the temperature of discharged water, and only short licences were available to use the water in this way. Fuel cells were less problematic.

Stillman has recommended a UTC Power 500kW Pure Cell fuel cell box for both buildings. At Arrowhead, this will provide 10% of the 50,000sq m building’s energy consumption, producing 250kW of electricity and 250kW of heat. As well as contributing 24 hours a day — it runs continuously — to the supply of electricity, and to space and water heating, the fuel cells help cool the building through an absorption chiller.

The fuel cells are housed in a 5m x 4m box some 3m high which will be located in the basement of the Arrowhead building. The cells run on hydrogen but will be powered initially using mains gas — which is 75% hydrogen — since no easily available hydrogen supply yet exists. They extract the hydrogen from the gas and convert it into electrical energy (see box). Water vapour, the waste product, can be extracted out of the building.

Maintenance is minimal, but every 10 years the box needs a new stack of fuel cells, and would need to be replaced in its entirety after 25 years. Its installation in the basement also has advantages for the developer in that it does not take up rentable space, places no physical constraints on future tenants, and has low operating costs.

At Arrowhead, the fuel cell will be part of a broader sustainability strategy, which includes a twin-skinned facade. SOM director Kent Jackson is hoping that the building, which has been built to basement level, will go ahead although the current economic climate is slowing it down.

“The client is very committed to making a good name for itself in terms of sustainability,” he says. “But for the building to go forward, a tenant is needed.”

Fuel cells are two-and-a-half times more carbon-efficient than a conventional CHP plant

 

Stillman, who has two toy cars powered by fuel cells in his office, is gung-ho about the application of fuel cell technology in buildings. “It’s not even the future, it’s now,” he says.

If he is right, then fuel cells in buildings will be no flash in the pan, leading in time to a hydrogen infrastructure network that will improve efficiency by enabling fuel cells to work directly off mains hydrogen.

Sustainability at Arrowhead

• Facade The proposed 26-storey Arrowhead development features a highly glazed twin-skinned facade that will help provide comfortable internal conditions year-round through a low-energy design.

In extreme temperatures, some heat build-up will occur within the facade. Heat is removed to prevent excessive temperatures adversely affecting the cooling systems. This is done by venting the facade cavity at every level with thin strips of high- and low-level vents.

• Fuel cell The scheme also features fuel cell technology for heating and ventilation.

• Photovoltaics Ten square metres of photovoltaics will be fixed to the roof. This will contribute to 0.1% of energy together with PIR (infrared) detection, which temporarily switches on lights in stairwells and other back-of-house areas where they are normally turned off.

Sustainability at Aldgate Place

• Solar shading The glazing will incorporate solar shading in the form of brises soleil, and all three buildings will feature fuel cell technology for heating and ventilation.

• Fuel cells Two fuel cells will provide a total of 400kW of electricity and 500kW of water heating. The hot water will be used either for heating in winter or for generating absorption cooling in summer.

Oliver Tyler, director at Wilkinson Eyre, says: “The key advantage at Aldgate, where we might have a phased development, is that fuel cells come in modules and are linearly expandable.

Fuel cells act like a CHP plant in that they produce both heat and electricity.”