Meeting targets to reduce carbon emissions by 2050

Carbon emissions from operating our buildings account for nearly half of the 550 MtCO₂ emitted annually in the UK, and must be tackled if we are to meet the target of an 80% reduction in emissions by 2050.  The mass roll-out of refurbishment measures is crucial in addressing emissions from existing stock, whilst the energy efficiency demands of new buildings are steadily increasing.  By 2016 for domestic properties and 2019 for others, all new buildings will be required to be ‘zero-carbon’ in operation.

Built to 2010 regulations, emissions from the construction of a typical masonry dwelling account for around 20% of associated carbon emissions over its life; by 2013 this will be more like 50%, and by 2016, all emissions associated with a dwelling will be embodied within the manufacture and transport to site of construction materials. It is crucial that we start assessing and taking action to minimise these emissions now.  At present, there is little legislation to promote the assessment of life-cycle emissions, although some guidance exists on methodology, most notably in the form of BS EN ISO14040/14044 and PAS2050.

Choosing Sustainable Materials

Assessment of the carbon embodied within a building project must occur both in the design and construction phases.  This is to allow feedback to practitioners on the accuracy of their predictions.  In design, a tool exists that can consider both simple and more complex designs, assessing an array of scenarios and making recommendations on how best to minimise embodied carbon.  Suggestions may include increased use of timber, waste product in cement production, or the sourcing of locally manufactured prefabricated components. It is clear that the use of renewable, recycled and local materials improves the environmental credentials of a development, but it is useful to quantify this benefit.  Life expectancies of different materials should also be accounted for.

Ideally, responsibility for data collection on-site would be allocated to an individual. However, all those involved in construction should be made aware of the process.  Keeping a record of materials delivered is standard site practice, but documentation should be widened to include information of the type of delivery vehicle and distance travelled.

There are well known tools for predicting emissions from operation of a building, including SAP and SBEM in the UK.  These may broadly estimate emissions from initial building services and design but they do not allow for changes in design and specification over a building’s life; it must be acknowledged, however, that this can be an extremely difficult thing to do.

Choice of materials and processes at the design stage will also impact on emissions at decommission.  Many materials can be reused or recycled, and practices such as use of lime-mortar, reduced use of paints and ‘design for deconstruction’ increases their potential. Constructing buildings with longer life expectancies and easily replaceable (yet durable) components reduces life-cycle impact.

Considering the Environment

Considering the environmental implications of materials and design over the life-cycle of a building can reduce emissions in all three phases of its life (i.e. construction, operation and decommission).  With zero-carbon targets fast approaching, such assessment is becoming vital. Developers who realise this will see benefits such as improved environmental credentials of bids for work, clear dedication to the sustainability of their projects, and crucially in the current climate, the ability to ‘outgreen’ their competitors.

Anthony Probert MSc AIEMA

Anthony Probert is Phlorum’s Sustainability Consultant and an expert in the sustainable design of buildings.  As well as a Code for Sustainable Homes assessor, Anthony undertakes SAP assessments, energy statements, renewable energy feasibility studies and life-cycle carbon assessments

Phlorum won a competition to display their Life-Cycle Carbon Footprinting model in the Innovation Future Zone at Ecobuild last month.

The project was deemed one of 20 innovations most likely to have a large impact on the environmental future of the construction industry, chosen from those who applied for the position to CIRIA. Anthony stood by the model for three long days explaining the rationale behind the method, and the potential of the model in reducing embodied carbon emissions. Such emissions will account for 100% of total emissions associated with a dwelling come 2016, when all new-build homes are expected to be zero-carbon. Through testing of scenarios, it was found that a dwelling built with environmentally friendly yet common materials (such as sustainably sourced timber) could attain a ‘zero-carbon footprint’ after 50 years with the aid of renewable technologies such as a biomass boiler and photovoltaic panels.

The event was a success, with many representatives of organisations displaying their interest in the final product, which is expected to be launched at the end of 2010. The video shows Anthony discussing the functionality of the model with an interested party.

Phlorum embodied carbon tool at Ecobuild 2010

Phlorum will be exhibiting their life-cycle carbon footprint model at Ecobuild. The model has been created as part of a Knowledge Transfer Partnership (KTP) with the University of Brighton, and the project is halfway through its two-year duration. Phlorum won the opportunity to exhibit through a competition run by the Modern Built Environment Knowledge Transfer Network (a subsiduary of CIRIA), which looked to find the most innovative and creative projects aiming to have an effect on sustainability of the construction industry in the UK.

The life-cycle carbon footprint calculator estimates the whole-life carbon emissions associated with new-build residential developments. This includes the carbon embodied within a dwelling, in its materials, methods and techniques of construction, associated with the use of the building, in the operation of its building services, lights and appliances, and emissions resulting from deconstruction or demolition of the building. The model is intended to be used as a design tool to reduce such emissions, promoting alternative materials and methods of construction, especially those with low embodied energy or embodied carbon. Use of the model could halve the amount of carbon embodied within the dwelling, and help with making the dwelling  ‘zero-carbon’ over its lifetime.

To see the model for yourself, come and chat with us at the innovation zone at Ecobuild, from Tuesday 2nd March 2010 to Thursday 4th.