The case for Centres of Excellence in sustainable building design

Low carbon construction
Low carbon construction
Construction is one of the largest industries in the UK, delivering just over 5%
of UK gross domestic product and employing some 2.3 million workers in 2009
[CITB, 2010a]. However, the industry lacks cohesion and the vision to deliver
large-scale change in the timescales necessary to achieve the UK’s climate
change commitments. The construction industry is highly fragmented and there
are many parties in the supply chain, none of whom holds overall responsibility
for delivering a building’s carbon performance.
In The Green Deal, government has set out very ambitious strategies for reducing
carbon emissions from buildings to contribute to the overall commitment of the
Climate Change Act. The method of funding the necessary works is still under
discussion, but is likely to rely heavily on private sector finance. However, the
private sector will not invest in technologies that do not provide a reasonable rate
of return no matter how great their contribution to achieving government policy.
It is vital, therefore, that this cornerstone of low carbon policy is supported by
an equally strong drive in the construction industry and amongst client bodies
towards delivering the necessary carbon abatement at the lowest cost to society.
Otherwise, with the influence of the feed-in tariffs, this policy may just divert
valuable funds into projects with short-term financial returns, but which, in the
main, do not deliver real carbon abatement.
The benefits of conservation
Using energy-efficient lamps does save energy compared
to conventional tungsten lamps, but due to the
inefficiencies in primary fuel conversion and distribution
the overal benefit is small. By comparison lighting a
building with daylight consumes no fossil fuel at all.
Every tonne of CO2 saved through energy efficiency measures represents energy
that does not have to be generated and distributed. Thus savings to the economy
accrue from energy efficiency, beyond the prime cost of the energy itself, as it
becomes unnecessary to build additional energy generation and distribution
infrastructure to serve growing demand and allows the existing infrastructure
capacity to continue to serve a reducing future demand.
Technology versus Technique
There are two ways of approaching carbon reduction from energy use in
buildings: to generate low or zero carbon electricity for supplying building needs,
or to reduce the energy demands of buildings in the first place through good
design, installation and operation.
In a typical contemporary commercial building about 75% of the total carbon
dioxide emissions are associated with the fixed building services, providing
lighting, ventilation and thermal comfort. These are the emissions regulated
under Part L of the Building Regulations. The remaining 25% of emissions relate
to the occupancy and business functions within the building and arise primarily
from the use of IT and office equipment and are unregulated.
Considering just the regulated emissions, mechanical ventilation and comfort
cooling represents about 35%, heating 25% and artificial lighting about another
25%. It is obvious therefore that avoiding or minimising the need for these artificial
forms of conditioning is paramount in developing energy-efficient designs.
Emission from all these areas of comfort design can be significantly reduced by
attention to the passive design of the building fabric to reduce reliance on active
systems. Further, designing the active system with knowledge of the passive
building response can deliver substantial gains in operational efficiency.
For example, electric light fittings are highly inefficient, converting about 90% of
the electrical energy input into heat and only 10% into visible light. Thus reliance
on electric lighting often leads to the additional need for comfort cooling,
The case for Centres of Excellence in sustainable building design 15