It was good news when the former Labour administration announced ambitions for all new housing to be zero carbon by 2016, and even better when the coalition affirmed its commitment to the pledge. But the ambition suffered a bit of a blow in March, when government announced its definition of zero-carbon would fall short of that outlined under Level 6 of the Energy Saving Trust’s Code for Sustainable Homes (CfSH) by not considering emissions relating to household appliances. The remaining emissions will be dealt with via the ‘Allowable Solutions’ part of the policy.

Volume housing developers would argue that achieving CfSH Level 6 is costly and that reducing the requirements will enable them to produce affordable homes and help the market out of recession.

However, Bill Dunster of sustainable property architects, ZEDfactory, disagrees: “We think that a Level 6 specification actually increases the sales value of properties, as these homes have virtually no energy bills and high consumer appeal.”

Dunster is working alongside developer BohoGreen and fellow architects Alan Phillips Associates on the PortZED development in Shoreham – a six-building, 67-unit, mixed-use development which will be designed to CfSH Level 6.

ZEDfactory is well known for its work on Surrey’s BedZED development, which in 2002 became the UK’s first and largest zero-energy development. Since BedZED, energy-generating components have been integrated into the building fabric, reducing a development’s resource requirements; PortZED’s PV and solar thermal panels, which will form part of the structure’s cladding, are an example of this. BedZED also revealed that super energy-efficient building fabric with high acoustic performance, which is important for building passive heat recovery systems, could be procured at a low construction price.

In terms of sustainability, the new development, PortZED has a lot going for it: its structure will be comprised of reclaimed steel and low-cement reclaimed aggregate blocks to minimise resource use. Energy usage will be reduced with high levels of insulation, and cool, radiant surfaces will enable passive cooling. Moreover, it will be powered entirely by microgeneration. The building’s south-facing seafront location lends itself well to this: photovoltaic and solar-thermal panels cover the southern facades and each building contains its own CHP generator, while an array of verticle-axis wind turbines is suspended between each block.

“Each building has been aerodynamically profiled to capture the predominantly south-westerly wind and accelerate it through the turbines”, explains Dunster. The wind turbines themselves have been specifically tailored for local conditions to boost their efficiency. Most off-the-shelf turbines are designed to operate most efficiently during maximum wind speeds, around 12 metres per second. “The average wind speed at the PortZED location is only around 5.4 metres per second, so we needed to design our turbines to produce maximum energy at this speed”, continues Dunster.

And the innovation doesn’t stop with simple infrastructure; behavioural change has been built into the plans as well. A series of tri-colour LED lights will be mounted on the wind turbines and glass balustrades and will glow red, yellow or green, depending on the individual building’s energy use. “The idea is to create competition between individual buildings to reduce their energy requirements”, explains Colin Brace, managing director at BohoGreen.

Residents will also be encouraged to form support groups to help each other minimise energy and resource use; waste will be tackled at-source through initiatives such as deliveries of package-free local organic food. A carpool powered by electricity and biofuel (made from recycled vegetable matter) will address residents’ transport issues, while a visitor centre with funding from the Technology Strategy Board (TSB) will provide information on recycling and energy-efficiency to residents and visitors alike.

“Our aim is to design a sustainable development, which will set an architectural standard for others to follow, in terms of sustainability and utilising the site’s natural features to assist in its energy generation”, concludes Brace.

The PortZED development is currently in final negotiations with planners and will go to committee in May 2011, with construction expected to commence in early 2012.