A substance that literally forms the foundations of urban living, concrete is indispensable to the way we live. Unfortunately, it is yet another example of a greenhouse gas emitting, unsustainable practice. In the era of climate change where our actions are subject to constant scrutiny, we cannot ignore the impacts of the cement industry. Enter green cement, the attempt by industry to enhance sustainability and reduce emissions.
Of global CO2 emissions, 5% come from the cement industry. The main ingredient in concrete, limestone, is a mining intensive resource that emits high emissions during manufacture. Greenhouse gas emissions come from the fuel utilised to heat limestone, and from the subsequent chemical reactions. At an extraordinarily cheap 15 cents per kg, we are not paying the true environmental or social cost of cement. (image: olovedog)
The future of green cement
Eco-cement is a ‘watered down’ version of conventional concrete, whereby waste materials are added to the mix. For some years now companies have been ‘blending’ cement with waste products from coal-fired power plants and iron manufacturing. Reducing the amount of limestone cuts energy costs and emissions. The result is a cheaper, lower carbon cement. Besides waste ‘blended’ cement, there are several other initiatives pushing the industry forward.
Companies such as LaFarge have produced an ‘aether’ cement that reduces emissions from 30% to 50%. Simply by changing the proportions of existing raw materials, the energy manufacturing needs have been cut dramatically.
Work is also being done to create a new cement which replaces energy intensive limestone with an alumino-silicate base. By switching raw materials, emissions from manufacturing can be curbed by 60%. Geopolymer cement is already commercially available.
Novocem is taking it even further. The company claim to be developing a carbon negative cement. This exciting new technology is able to absorb up to 100kg of CO2 per tonne. This cement is still very much in the experimental phase, but Novocem hopes to be producing 25,000 tonnes a year by 2015.
How can we support green cement?
The most obvious way we can support green cement is to increase consumer demand. Consumer reluctance is the key issue standing in the way of success. Companies are wary to invest in a product that has not yet stood the test of time. No-one wants to be the first to try out new technology. If enough companies and individuals phase low carbon cement into their building materials, it should strengthen confidence in the long term.
Don’t wait for the technology – act now
As the technology develops, here are some steps you can take in the now:
Insipid yet integral to our lifestyles, it is time to stop ignoring the impacts of concrete manufacture. The cement industry will play a big role in emissions reductions in the years to come. With the improvements in technology, there are many ways to support the development of green cement. Perhaps Amory Lovins of the Rocky Mountain Institute sums it up best by saying that green technology “will happen, and happen rapidly– because it’s profitable.”
Acacia Smith is a New Zealander now based in London. She holds a bachelor degree and postgraduate diploma from Victoria University of Wellington. She has worked for the Council for International Development (CID) and more recently in Bolivia for CIWY, a network of private parks for the rehabilitation and conservation of Amazonian fauna. Acacia is passionate about sustainability and the role businesses can play in promoting a better, more sustainable future.