Cutting the carbon legacy

Altered environmental attitudes in the construction industry must be among the biggest changes seen in business. Today’s approach of the multinational Swedish construction company Skanska seems a million miles from that of the energy-guzzling, polluting operators of the late 20th century.

Skanska is proud that an increasing number of projects develop carbon policies that are focused on minimising its greenhouse gas emissions and creating financial savings at the same time.

The company breaks its carbon policy into two categories. First, it considers ‘embodied carbon’, the total emissions produced in the course of a project’s construction. Then it turns to ‘operational carbon’, if the opportunity of influencing the design and operation exist.

Skanska defines operational carbon as “the emissions associated with the heating, cooling and electrical consumption of a building during its operational life-span”. In other words, Skanska takes responsibility for the emissions it emits while working on a project and for the potential emissions from the finished product after it is handed over.  

The choice of materials plays a major part in minimising a project’s environmental impact. For instance, where it is possible without compromising quality, Skanska focuses on the recycled content of materials – such as recycled steel and cement, and concrete made from flyash, a by-product of coal-fired generating plants.  

One project in Sweden substituted concrete drainage pipes with those made from polyethylene, creating carbon savings of around 40% – or 100 tCO2e (tonnes of CO2 equivalent) – and reducing project costs by $115,000. When it took on a project in Telemark, Norway, it used, for the first time, prefabricated concrete hollow core floor panels, containing cement with 30% flyash, reducing embodied carbon by 30%.

Materials use played a similarly effective role in Skanska’s road-widening scheme on 60km of London’s huge M25 orbital motorway. The company used sheet piles made exclusively from recycled steel and 2.4 million tons of recycled aggregate, and processed demolition waste from the excavation and other construction sites. These steps saved around 103,000 tons of CO2e, meaning an emissions cut of 27%. Cost savings related to the recycled aggregate alone was estimated at $23m. Skanska quotes this work as illustrating good environmentalism in demolition, as well as in actual construction.

On a second UK project, an infrastructure upgrade for a number of Anglian Water sites, Skanska helped develop an intranet-based carbon modelling tool, creating embodied carbon economies of up to 27%, or almost 2,000 tCO2e, while potentially halving operational carbon each year – 600 tCO2e – representing a $70,000 saving.

The delivery of materials is another area on which Skanska looks to make environmental savings. Consolidating deliveries and cutting transport pollution and vehicle use are effective methods of bringing down both emissions and costs, and also promote safety on site.

Skanska also looks at other forms of transport. For example, prefabricated parts for the Clarion Hotel Sign, the biggest hotel in Stockholm, were transported from Slovakia by train. This method of moving supplies avoided 235 tCO2e and was 10% cheaper than road haulage. In Skanska’s Finnish projects, consolidated just-in-time deliveries were believed to have halved carbon emissions.

An important part of the embodied carbon calculation is the efficiency of the on-site temporary buildings. So, here, the accent in the cabins is on economic energy and lighting use, for instance, as well as insulation and double glazing.   

An equal amount of attention is paid to operational carbon policy. After a project is transferred to the client, Skanska typically has no further control, so it has to be handed over in an environmentally acceptable state. The design team’s most efficient energy and ventilation systems are installed, using alternative energy sources where possible, as well as insulation as effective as it can be.

Such care and precision in a construction company requires that suppliers, too, are environmentally responsible. Skanska’s procurement units are increasingly examining their suppliers to ensure the goods have been produced according to low-carbon methods – close co-operation between the company and its supply chain is the order of the day.  

A element of every project is the promotion of the company’s own staff for assessment and consultancy, in preference to outside advisers. Johanna Wikander, Skanska’s green support manager, observes: “The advantages of having competency in-house is that we can develop our business in a proactive way instead of just reacting to customer demand and buying competency externally. With competency in-house, Skanska can develop solutions together with the client.”

The company’s vigilance over its own performance is shown by an interesting shift in emphasis. Until recently, embodied carbon typically accounted for a fifth of the emissions savings, and operational carbon 80%. But as the company builds more energy efficient projects and adds renewables to the mix, this ratio is shifting. Embodied carbon is rising rapidly as a proportion of overall emissions and Skanska is, consequently, particularly targeting it.

The carbon footprint is measured with a range of “very straightforward” tools, says Wikander. “You combine quantities of materials with an emissions factor, for instance, and the result is your emissions are related to that use. Generic data is used where necessary, but the use of more project and supplier specific data is encouraged where possible.”

Skanska conducted 36 carbon footprint studies in 2011. Wikander says: “The main thing we learnt was that interest in carbon footprinting is increasing, so we expect the figure to be much higher in 2012.”

Despite the interest reported by Wikander, obtaining information on suppliers’ materials is a big problem, because people within the industry are slow to communicate. She says: “Some of our big suppliers know about these things, but it is down to internal communication. The research and development team for a cement supplier, for example, is well-placed, but it doesn’t communicate with other parties. It is a challenge to get the information out from sustainability and R&D teams to the projects.”

Another hurdle is a general lethargy about green principles – or even apathy. The enthusiasm for environmentally responsible business practice and sustainability is growing, but it is still the preserve of a minority. Nevertheless, Skanska itself has found “clients are increasingly demanding carbon footprinting services”, particularly, reports Wikander, is in the UK and Norway.

Skanska is trying to persuade clients and other construction companies that there should be national emissions benchmarks for the industry, drawn up by a third party. However, Skanska does appear to have set its own demanding standards. “We are the front runners,” says Wikander. She adds, however: “Footprinting is not about exact numbers. It is more about a way of identifying your hot spots, which are the bad areas that need to be remedied, offering opportunities to improve.”  

Meanwhile, as a way of spreading the word, the company has set up a strategy called Journey to Deep GreenTM, with zero environmental impact as the end target.