BioRegional response to zero carbon homes

BioRegional's response to UK government's announcements on zero carbon homes.

The Chancellor and the Secretary of State for Communities and Local Government have made announcements over the last two weeks outlining challenging new UK government policies and incentives for zero carbon homes and communities.

As the BedZED eco-village is the most well known and largest example of a zero carbon development in the UK, this naturally has led to a lot of interest over the last week in how things have worked out at BedZED.

The fact that the BedZED wood fired combined heat and power plant has not been operational for over a year naturally led to slightly unfair and sensational headlines like "Great Green Gimmick" (Daily Mail, 8 December 2006).

In response to this we have set out below the current situation at BedZED for those of you who would like to know more and in the attached box some more information about the UK government proposals.

UK Government Proposals for Zero Carbon and Sustainable Homes announced in December 2006.

Zero carbon new homes:.

- By 2016 all new homes in UK to be zero carbon, with a 25% improvement on energy use on current building regulations by 2010 and a 44% improvement by 2013.

- Exemption from stamp duty tax for zero carbon homes from April 2007.

DCLG's definition of zero carbon is shown below.

Code for Sustainable Homes - a voluntary code which will become mandatory as part of the building regulations in 2008.

Code level 6 is a zero carbon home.

Planning and Climate change.

The proposals were developed in consultation with WWF-UK and the Home Builders Federation amongst others.The UK government invites comments on the proposals.Comments can be e-mailed to buildgreen@communities.gsi.gov.uk by March 8th 2007.

Government definition of a zero carbon home (taken from DCLG press release 13 December 2006).

A zero carbon home is one with 'zero net emissions of Carbon Dioxide (CO2) from all energy use in the home'.

The definition encompasses all energy use in the home (including energy for cooking, TVs, computers and other appliances) rather than just those energy uses that are currently part of building regulations (space heating, hot water, ventilation and some lighting).

It means that over a year there are no net carbon emissions resulting from the operation of the dwelling.

This could be achieved either through steps taken at the individual dwelling level or through site wide strategies.

So it will not be necessary for each dwelling to have its own microgeneration capacity where development level solutions would be more appropriate.

BedZED eco-village - the prototype for zero carbon homes in the UK.

BedZED is the UK's largest eco-village and is a Peabody Trust development in partnership with BioRegional and designed by Bill Dunster Architects.

BedZED was designed to be a zero carbon development - for us this means to:.

1.

Reduce the demand for energy through.

- high levels of insulation and use of natural light and passive heating and ventilation.

- inclusion of low energy appliances and light fittings in all the homes.

2.

Supply the remaining energy required from renewable sources which do not contribute to the devastating effects of climate change.

Whether a development can be zero carbon on its own site or whether it will need to draw renewable energy from the grid will depend on the availability of local resources, for example high wind speeds, sunlight or surplus biomass.

All zero carbon developments will need to be connected in to the national grid in order to deal with fluctuations in energy generation and demand.

In the case of BedZED, BioRegional organised the supply of wood waste from local street tree pruning to power an on-site wood powered combined heat and power plant (CHP) to produce hot water and electricity.

Photovoltaic panels were also incorporated into the design of the homes to generate electricity from the sun.

This strategy makes BedZED net zero carbon on-site.

The government definition of zero carbon is shown in the box above and seems to suggest that all energy should be generated on site.

However, BioRegional's view is that generating all the energy on-site from renewable sources, whilst it is the ideal and attractive option, is not always possible or the best thing to do.

It might be better to generate some of the energy off-site or from larger renewable energy plants supplying the wider community.

In all cases it is necessary to establish an energy service supplier as developers themselves are really in a different business.

Therefore BioRegional suggest that the government needs to consider how to bring the utility companies into the zero carbon homes consultation.

One other factor which BioRegional believe the government should take into account would be a fairer price for energy produced by small scale renewable energy generators.

The renewable energy produced at BedZED or comparable projects- who have to be connected to the grid to even out demand fluctuations - is purchased for a substantially lower price than the energy pulled off the grid.

In Germany the price paid is the same whether you are buying or generating and in California a premium is paid for renewable energy.

A fairer price would improve the returns on investment for renewable energy producers and encourage a much wider take up.

The BedZED CHP plant was operational at times during 2002-2005 making BedZED carbon-neutral whilst it was running, but being a prototype there were some problems with the technology and the conditions under which it could operate.

The main difficulty was the tar content of the wood gas which built up in the engine used to generate the electricity, this was exacerbated by a planning condition which meant that the plant was required to shut down overnight, which caused further problems with tars forming as the equipment cooled down.

Engineers will tell you that most process equipment operates much more smoothly if you keep it running continuously.

Unfortunately the supplier went into administration before they were able to solve the technical problems.

The plant has not been running for over a year during which time BedZED has drawn electricity from the grid and produced hot water from efficient on-site gas condensing boilers.

Although BedZED is therefore not zero carbon at the time of writing, compared to a similar home built at the same time BedZED has reduced its carbon emissions by 56% through insulation, double and triple glazing and energy efficient appliances and light bulbs and the photovoltaic cells which supply 11% of the site's electricity.

BedZED residents save money on their fuel bills because they use half as much energy, which for a family home can amount to savings of GBP500 per year.

The intention is to make BedZED 100% zero carbon again in the near future.

The BedZED development team are speaking with another renewable energy company about installing a new system.

It is important that the new equipment is reliable and the team are taking their time to investigate the technologies and proposals very carefully before making a decision.

Building on lessons learned at BedZED, BioRegional are also working on next generation zero carbon communities.

For the past two years BioRegional have partnered with WWF on an initiative called One Planet Living, one aim of which is to work with local partners to build sustainable communities around the world.

The communities are guided by a set of ten principles - one being zero carbon.

www.oneplanetliving.org For the One Planet Living London project, which will be zero carbon, we are working with sustainable community development company BioRegional Quintain (1) to find a site in London's Thames Gateway to build a 2,000 home mixed use development there.

Research carried out by BioRegional on this project, known as Z-squared, is available on our website (View the report here).

BioRegional Quintain are already going ahead with sustainable communities in Brighton (with Crest Nicholson) and Middlesbrough, with building starting on site in 2007.

BioRegional will be responding to the government consultation on the zero carbon policy proposals and passing on our practical experiences outlined above.

It is not entirely simple to build new zero carbon developments but BioRegional have applied the approach in a variety of scenarios now and we can see how it will be both technically feasible and cost effective.

There is a zero carbon development in Malmo, Sweden (view details here) and a number of smaller zero carbon developments in the UK and around the world.

In the coming year BioRegional is turning its attention to practical demonstrations of zero carbon and One Planet Living in existing communities.

In the wake of the UK's Stern Review it is accepted that it makes economic sense to tackle climate change now.

BedZED has played a key role in achieving these world first zero carbon policy proposals from the UK government by showing in a real and practical way how zero carbon homes can be a part of the mainstream.

Sue Riddlestone, Director, BioRegional Development Group, 20th December 2006.

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