Emission calculation of infrastructure construction brings low carbon to planning and budgeting

The purpose of the report commissioned by the KETO project of the Centre of Excellence for Sustainable Development was to determine the baseline to which future climate work can be compared. In addition, it makes it possible to assess the effectiveness of more climate-friendly measures, that is, which emissions should be reduced the most. In this way, the measures and costs of emission reductions can be prioritised in order to keep the projects within the budget.

“However, the current report is only a starting point from which to develop emission calculation,” says Iina Kallio, a project planner at the City of Espoo specialising in the circular economy and sustainable development of infrastructure construction.

Emission calculation of infrastructure construction is a continuous process that will develop to be more accurate over time. At the moment, not all data is available for different emission sources, but in the future, as the supply of emission data develops, the calculation will also become easier.

At the turn of last year, the Finnish Transport Infrastructure Agency published a collection of emission data, the maintenance and development of which is the responsibility of the Finnish Environment Institute (Syke). The objective emission data of public operators provides useful information for calculating the city’s emissions and for the competitive criteria of contract procurement.

“If, for example, the emission limit for the transport of natural stones is used as a minimum criterion in the contract invitation to tender, the information must be impartial, so that competitive tendering can be carried out fairly according to the Act on Public Procurement,” Kallio points out.

According to the emission report, the materials used in infrastructure construction and their treatment caused 92 per cent of the aforementioned total emissions of 33,000 t CO2e. The rest of the emissions came from maintenance work. More significant than the amount of emissions, however, is where the emissions come from. When the largest sources of emissions are known, they can also be more effectively addressed.

“Approximately 82 per cent of the emissions from infrastructure construction are caused by the manufacture of building materials, especially concrete and steel. The rest is divided fairly equally between transport and work performance,” says Saila Vicente, designer at Ramboll Finland Oy, who was responsible for the report.

“However, low-emission materials are already available. For example, low-carbon concrete is already available and the price difference to the corresponding traditional product has shrunk. Large-scale production of zero-emission steel is also about to start,” Vicente says.

Climate-friendly materials may also be cheaper than those traditionally used. For example, low-carbon materials that cost less than virgin materials can be produced from the side streams of industry or through recycling. As an example, Iina Kallio mentions the recovered materials used as binders in soil stabilisation, which offer not only significant emission savings but also a cost advantage.

However, when using more climate-friendly materials, one should not only think of the price. The technical functionality of the materials must also be in order and approved by experts. Testing new materials with pilots, for example, is therefore necessary in order to obtain practical information on their geotechnical functionality, such as the load-bearing capacity and frost susceptibility of the land. Cooperation between cities enhances the utilisation of the information obtained in the experiments.

“Ensuring quality and sustainability increases the courage to use recycled materials and more climate-friendly practices in infrastructure construction,” Kallio says.

According to Ramboll’s report, potential calculated measures could cut emissions by up to 30 per cent. This includes low-emission materials, the optimisation of transports and the use of domestic natural stones instead of imported stones.

“Large quantities of rocks and soil are transported from and to construction sites. In addition, soil work produces emissions,” Vicente says.

Transport and work performance account for approximately 16 per cent of the total emissions from infrastructure construction. Therefore, attention must also be paid to them. In site operations and transport, for example, efforts are made to switch to green electricity and renewable fuels, which reduces not only emissions but also noise and dust.

Emissions calculation and emission budgeting are likely to become an integral part of the overall calculation of contracts in the future.

“We are not quite yet at the point where the share of emissions is calculated every time in project budgets, but in the future, it will become an established practice and part of everyday life,” Vicente says.

“The report provides a basis for identifying emission sources and seeking low-carbon solutions. In the future, the aforementioned databases, for example, will help with the calculation,” she adds.

A climate budget is also being prepared in Espoo, which could be used to earmark money for reducing emissions.

“At the moment, low emissions must practically not cost much extra,” says Iina Kallio.

“We have tried to balance emission saving measures so that some of them create costs and others save them. Large savings – in terms of both euros and emissions – are achieved, for example, by using demolition concrete in filling in earthwork. In that case, there is no need to get virgin rock material,” she adds.

Espoo uses the cost accounting service of the Infrastructure Cost Management System (Ihku) alliance, whose accounting system is currently being developed so that, in addition to costs, the system will also determine the emissions of the components.

“In the future, with the help of Ihku, it will be possible to assess the emissions of different materials and works already at the planning stage of the infrastructure contract. Then we can choose a lower-emission method or enable it alongside the usual solution when preparing the contract invitation to tender,” Kallio says.

In achieving the calculated carbon neutrality target, carbon sinks and stocks are also taken into account. This provides an opportunity in infrastructure construction to balance total emissions, as forests, green areas and parks belonging to the sector are actively included in the emission calculation. The importance of nurturing biodiversity is increasing all the time, and it is an essential part of climate work.

Emission calculation in infrastructure construction has a clear goal in Espoo.

“Carbon neutrality by 2030. Achieving that goal involves many different milestones and measures: increasing the understanding of emissions, the circular economy, resource wisdom and increasing the carbon handprint – the whole big picture,” Kallio says.

“In most cases, all sectors win when individual factors of climate positivity are promoted,” she concludes.

The emission report for infrastructure construction was implemented as part of the Implementation Pathway for Environments that Accelerate Sustainable Growth project (KETO), which is implemented with the European Union’s REACT-EU ERDF funding. The financing is part of the European Union’s response to the COVID-19 pandemic.

The KETO project develops cooperation between businesses, educational institutions and research organisations and creates concrete development environments to promote the green transition and digitalisation.