Critics of the concrete industry often ignore the significant energy and CO2 reductions that it has made and is committed to making still further, explains Andrew Minson, executive director of The Concrete Centre.
Critics of the concrete industry often point to the energy intensive production of cement and resultant carbon emissions, but fail to take account of the fact that the inherent thermal efficiency of concrete provides more potential to reduce the long-term operational energy use of buildings than any other construction material.
The majority of embodied CO2 within concrete comes from the cement element. Cement manufacturers have addressed this issue with an environmental programme that has seen the amount of CO2 emitted for every tonne of concrete produced fall from 103kg in 1990 to 88kg today. By 2012 the target is to further reduce this to 85kg.
The cement sector has committed to voluntary climate change agreements (CCA) with the Government and has exceeded its energy reduction targets. The sector has improved its CCA performance by 33.7% between 1990 and 2008.
This improvement is mainly due to the use of alternative fuels, particularly those containing biomass. In fact, cement manufacturers are now among the leading exponents of alternative fuel use, with material diverted from the waste stream for use as fuel accounting for 17.4% of the total energy used in concrete manufacture. By 2012, the industry is committed to increasing this figure to 21% so that, as a whole, the concrete industry CO2 emissions from production will be 17% lower per tonne than they were in 1990.
There has been considerable investment in new plants that can use alternative fuels. Following successful trials and emission testing, these are now coming on stream. This investment is now paying dividends in terms of reduced energy use and CO2 emissions.
With the day-to-day running of our buildings being responsible for nearly 50% of total UK CO2 emissions, it is essential that the energy efficiency of the built environment goes beyond the embodied CO2 emissions of construction materials and addresses the long-term operational emissions of buildings.
The inherent thermal mass of concrete can provide considerable energy savings over the lifetime of a building in terms of reduced heating and cooling requirements. Thermal mass relates to the ability of construction materials to absorb heat. On hot days this helps to cool the internal temperature and prevent overheating problems without recourse to energy intensive fans or air conditioning. Night time natural ventilation removes the stored heat. During the winter, the absorbed heat is kept within the building to help maintain a constant warm ambient temperature that reduces the need for heating. Utilising thermal mass as part of an overall passive sustainability design strategy can significantly reduce heating and air conditioning requirements.
The most useful levels of thermal mass are found in medium and heavyweight construction using concrete and masonry. Lightweight materials such as timber and steel cannot match these levels.
The reality is that not only is the concrete industry making considerable strides in reducing its embodied CO2 emissions, but in addition concrete has a beneficial role to play in reducing operational CO2 emissions through its incorporation in passive sustainability design and construction strategies. Its inherent thermal efficiency offers real long-term operational energy savings by reducing heating and cooling requirements.
In order to provide the concrete facts, the concrete industry has just published its second annual Concrete Sustainability Performance Report. The report signifies a further milestone towards the fulfilment of the vision that, by 2012, the UK concrete industry will be recognised as being the leader in sustainable construction.
The new report builds upon the first report published in 2009, which provided industry data across 14 performance indicators against which the concrete sector has committed to be benchmarked against and to improve upon. The latest performance report provides 2008 performance data and publishes 12 targets, plus more in development, to be achieved by 2012.
These are real targets that the concrete industry is committed to achieving and, where possible, to exceeding, and it should be applauded for its efforts to contribute to sustainable development. The targets are indicative of the industry’s objective to be recognised as the leader in sustainable construction.
The publication of the second performance report follows the concrete industry’s agreement in 2008 to sign up to a Concrete Industry Sustainable Construction Strategy. The pan-industry agreement called for a commitment for the development of industry performance indicators and for achievement of set targets.
In addition, the concrete industry is the first industry to link its sustainable construction strategy to the responsible sourcing standard developed by the Building Research Establishment, BES 6001 – Framework Standard for the Responsible Sourcing of Construction Products. This demonstrates the sustainability credentials of the UK concrete industry and allows designers and specifiers to easily source accredited material and gain maximum credits in sustainability assessment tools such as the Code for Sustainable Homes and BREEAM.
The publication of performance data and targets reflects the concrete industry’s commitment to transparency and continual improvement. These are not vague promises but commitments to real action that will build upon the good work already achieved and on the inherent sustainable performance benefits of concrete.
To download a copy of The Concrete Industry Sustainability Performance Report visit: www.sustainableconcrete.org.uk