>> Homes built in England to increase to 200,000 each year by 2016
>> Local government to play 'crucial role'
Chancellor Gordon Brown's announcement in his pre-Budget statement that all new homes would be 'zero carbon' by 2016 was not just a strike at being green by the Labour Party, but also a pledge that, assuming he becomes the next prime minister, Mr Brown could be held personally responsible for delivering.
It seemed strange, then, that in the days after the report, the government did not seem able to provide any real detail on what the chancellor had meant. What exactly is a zero-carbon home? And how many have been built?
On the last question, the Department for Communities & Local Government was cagey. A spokeswoman would reveal only that there were 'very few', which appeared to be a catch-all term to cover more than three - the number of specific case studies she had to hand - but less than 10.
The move from a baseline in single figures to all new homes being zero-carbon within a decade is an ambitious, if admirable, aim. But it is not the only target for 2016.
The chancellor's zero-carbon vision comes on top of another significant goal: to increase the number of homes built in England each year to 200,000. Again, this represents a significant leap - in 2004-2005 around 168,000 homes were built.
Is it possible to meet both targets, or is there a risk that one will undermine the other? And what should councils - which have strategic housing responsibilities, planning departments and a moral duty to champion
environmentalism - do to help ensure both targets are delivered?
With the publication of consultations on a new planning policy statement on climate change and Building a greener future: towards zero-carbon development, it has at least become clearer what a zero-carbon home is and how the government would like to see the target met by 2016.
The DCLG is proposing two interim targets, culminating in across-the-board zero-carbon development by 2016. 'Zero-carbon means that, over a year, the net carbon emissions from energy use in the home would be zero,' the consultation says (see box).
Communities and local government secretary Ruth Kelly stressed councils have a vital part to play. 'Local government's crucial role will be to find solutions that work for local communities,' she said.
Alongside the consultation documents, Ms Kelly also announced an independent review of house building delivery to be led by John Callcutt, chief executive of regeneration agency English Partnerships and former chief executive of house builder Crest Nicholson.
Mr Callcutt admits meeting both the zero carbon and housing supply targets by 2016 will be a challenge, but says: 'That's frankly why I'm here [doing the review].'
He adds: 'One expects local authorities to be an integral part in driving forward housing supply.'
John Slaughter, director of external affairs at the Home Builders Federation, says councils must play an enabling role. 'I think it is a question of local authorities being willing to talk to developers at an early stage about how they see the issues relating to climate change so that they can be planned into developments rather than coming as a surprise,' he says.
But even where developments are planned to be environmentally friendly, they do not always live up to expectations. The Beddington Zero Energy Development (BedZED) in Sutton, south London is probably the best-known low-energy development. But despite its name, at the moment it can only claim to be low, rather than zero, carbon. Its construction also ran significantly over budget.
Adrian Hewitt, principal environment officer at Merton LBC, who has worked on research for the Centre for Sustainable Energy, says a BedZED-type scheme would be too expensive to work in most places.
'The problem with the BedZED model is the additional build cost is so high that it makes it very difficult to get a scheme like that up and running.'
Instead, councils should focus on developing and providing new energy technologies such as district heat and power, he says. 'One of the ways of going zero-carbon would be if your combined heat and power plants are running off some renewable energy.'
But Mr Hewitt admits that there is a 'potential clash' between the zero-carbon and housing supply targets.
If both are to be met, there is undeniably an argument for closer working within councils, which tend to volunteer staff from their housing strategy teams to talk about the supply target, and officers from environment departments to talk about zero-carbon.
Jim Bennett, senior research fellow and acting head of social policy at the Institute for Public Policy Research, says increasing supply, reducing costs and lifting environmental and design standards must go hand in hand.
'Inevitably there are trade-offs that potentially could come between those different imperatives. The issue with the zero-carbon target is that it's going to require a significant modernisation of the whole approach of the industry as well as the regulatory framework for housing.'
Mr Bennett says that, arguably, the model for producing housing will have to change: 'Housing delivery needs to be a much more joined up and coherent process. There's a need for planning to be talking to environment people.'
Sarah Webb, director of policy and practice at the Chartered Institute of Housing, agrees. She also calls for work to be undertaken to clarify the true costs of the zero-carbon target - costs described as 'uncertain' by the government in its consultation.
But there is plenty councils can do to help meet the targets, Ms Webb says.
'If you really wanted to make a positive stand as a local authority you would say 'we will give faster planning permission for private developers that start taking this agenda seriously'.'
Councils could also play an important part in providing information for consumers, 'a bit like public-health campaigns', helping them to drive zero-carbon development by knowing what questions to ask house builders or estate agents about new homes' eco-credentials.
But Ms Webb is concerned about one housing target putting the other at risk - describing it as inconceivable' the zero-carbon target will not impact on the delivery of the new homes target.
Whatever the risks, both housing and environment policy developers are agreed that urgent action is needed.
Simon Roberts, chief executive of the Centre for Sustainable Energy, says councils can be at the forefront of trying out what works by, for example, providing land for test beds for zero-carbon developments. They also have a vital training and skills development role.
Local government has a major part to play in helping to ensure that by 2016 there are 200,000 homes built each year and all of them are zero-carbon. It will undoubtedly be challenging but, as Mr Roberts puts it: 'There's really no alternative.'
Ambitious targets will bring big opportunities, says Christoph Sinn
The government's plan to move towards all new homes being zero-carbon by 2016 is ambitious. In fact, the UK will be the first country to commit itself to a strict timetable to achieve this.
The technology to build zero-carbon homes is readily available and has been tried and tested in a number of developments, both in the UK and abroad.
Housing built to the German Passivhaus standard reduces domestic energy requirements by 90%, with the remainder generated from on-site renewable energy sources. Around 6,000 homes throughout Europe have been built to this standard.
The BowZED development in east London is a UK example of a zero-carbon development, generating as much energy from renewable sources in a year as it consumes (see picture).
But will it be possible to build to zero-carbon standards and meet the government's house-building targets, which are set at 200,000 net additions per year over the next decade?
It is simply too early to say. In order to make a proper assessment, we need answers to the following questions.
>> Is the current technology fit for purpose?
>> Will councils have enough freedoms to make the planning system work in favour of zero-carbon developments?
>> Are we clear about the costs involved on a large scale, and who will pay given the efficiency targets facing the sector?
>> Do we have the skills needed to build zero-carbon homes on such a scale?
The Environmental Change Institute at Oxford University carried out research on the feasibility of achieving carbon reductions of 60% in our homes. It concluded that a huge training programme is needed to address the skills shortage to build and maintain a low carbon stock. But this gap represents an exciting opportunity in terms of employment and training in the coming decade.
We should not be put off by the task ahead, but welcome the opportunities this will bring. The government should be applauded for taking this bold step, which will lay the foundations for a lasting legacy for generations to come.
Christoph Sinn Policy and professional practice officer, Chartered Institute of Housing
Taking aim at energy
Proposals for zero-carbon homes target
>> By 2010 new homes should be 25% more energy-efficient than they are now.
>> By 2013 they should be 44% more energy-efficient than now.
>> By 2016 they should be zero-carbon.
>> 'Zero-carbon' means that over a year the net carbon emissions from energy use in the home would be zero.
Housing supply target
>> A new target to provide 200,000 additional new homes each year by 2016. In its December 2005 response to the Kate Barker review of housing supply, the government said: 'Current projections suggest that if government is to meet its aim to improve affordability, new housing supply in England will need to increase
over the next decade to 200,000 net additions per year.'