It is essential to focus on the acceleration of new developments and technologies that reduce carbon emissions in order to realise climate neutral infrastructure. This is one of the most important findings of the research ‘On the road to climate neutral infrastructure in the Netherlands’ conducted and published by SKAO and the Technical University of Delft (TU Delft). So which sustainable innovations actually contribute to climate neutral infrastructure in the Netherlands?
The research report ‘On the road to climate neutral infrastructure in the Netherlands’ was published in 2018. At this moment, the report is only available in Dutch. The research project is supported by the Dutch ministry of Economics (MVI-Energieproject, Topsector Energie). The research resulted to transition scenarios of the most widely used materials in the Dutch infrastructure sector, namely concrete, asphalt, steel and fuel. These material chains describe different scenarios that enable a climate neutral infrastructure sector.
In this article, SKAO examines the sustainable innovations and developments of each material chain that contribute to the realisation of climate neutral infrastructure in the Netherlands. The opportunities for circularity and CO2 reduction are highlighted in each paragraph containing information about the material chains. Moreover, the article discusses how to accelerate the transition to climate neutral infrastructure.
The research on climate neutral infrastructure showed that the production of cement causes the greatest amount of carbon emissions during the production process of concrete. 70 percent of CO2 emissions that are released during concrete production is caused by cement, according to the researchers of TU Delft and SKAO. For this reason, the researchers see opportunities for sustainable innovations that cut back carbon emissions of concrete caused by the production of cement.
New technologies that reduce carbon emissions of cement production consist of new types of cement that make use of different minerals. An example of this is geopolymer cement. This material replaces cement in concrete by using mineral residues, alkalies and patented additives. Due to the minerals used in the geopolymer cement mixture, it can reduce up to 80 percent of carbon emissions during the production of concrete. In the Netherlands, geopolymer cement is already used in the construction of a carbon negative high road between the cities of The Hague and Poeldijk. However, the researchers question whether the use of alternative cement types will actually be scaled up, because the resources and minerals to produce these alternative and sustainable cement types are not widely available. Nevertheless, the minerals of the alternative cement types have proven to successfully reduce carbon emissions during concrete production, which makes it a viable option.
Next to replacing cement in concrete, the research shows opportunities in terms of circular concrete. Circular practices can be made possible by reusing cement at the end-of-life phase of concrete. An example that enables reclaiming and reusing cement is the ‘Smart Liberator’, a machine that reclaims cement from used concrete. The reclaimed cement can then be reused as a foundation for roads, but also to produce new concrete.
Asphalt is predominantly used in the infrastructure sector. The biggest amount of carbon emissions is released during the production of asphalt and leads to 42 percent CO2 of the total amount of emissions caused by asphalt, from production to usage. The remaining materials used for asphalt production, namely the binding material bitumen, causes 10 percent of the CO2 emissions resulting from asphalt production and usage.
The production of asphalt leads to a large amount of CO2 emissions due to the heating process to mix the ingredients of asphalt: minerals (sand, grind and rubble), limestone or ash and the binding material bitumen. In a traditional asphalt production process, the ingredients of asphalt are heated up to a temperature of about 180 degrees Celsius. In the short term, the researchers therefore see opportunities to produce asphalt at lower temperatures to reduce the carbon emissions released during the asphalt production process. In the Netherlands, the construction firm BAM Wegen works alongside Rijkswaterstaat, the operational organisation of the Dutch ministry of Infrastructure and Water management, to produce low temperature asphalt called LEAB PA. This asphalt is produced at a temperature of 110 degrees Celsius, which leads to energy savings and therefore CO2 reduction. Next to that, production of asphalt at a lower temperature has a positive effect on the durability of the asphalt road, according to the collaborating organisations.
The researchers conclude that asphalt provides plenty of circular opportunities, such as the recycling of used asphalt that can lead to great amounts of CO2 reduction in the asphalt chain. The researchers expect that 95 percent of asphalt can be recycled depending on the availability of secondary asphalt. The Dutch construction firm Strukton Civiel has proved that it is possible to produce asphalt that consists of 97 percent of reused materials. The so-called Greenfalt is made from reused asphalt and recycled ballast materials from railways. The reused materials are processed in all layers of the asphalt road, from the foundation till the top layer. According to Strukton Civiel, the quality of Greenfalt is comparable to the quality of traditional asphalt. Next to preserving virgin materials, the use of Greenfalt leads to CO2 reduction through less transport of the virgin materials. Due to its composition, the materials needed to produce Greenfalt do not end up in landfill, which leads to more carbon savings.
Fossil fuel and energy usage leads to a great deal of carbon emissions in the infrastructure sector. The research ‘On the road to climate neutral infrastructure in the Netherlands’ points out different categories in which energy and fuels are being used. The categories are transport on water, transport on land and the use of building materials. The researchers refer to the ambitions of the Dutch ministry of Infrastructure and Water management to highlight the opportunities for a transition to sustainable fuels.
The Dutch ministry of Infrastructure and Water management strives towards a CO2 reduction of 60 percent for transport on land in 2050. This CO2 reduction objective includes all road transport and freight transport in the infrastructure sector. In order to achieve this objective, it is essential to invest in sustainable innovations in terms of fuel and energy. The ministry seeks opportunities in electric vehicles, because these vehicles are most efficient for transporting goods on land. Moreover, electric vehicles can reduce carbon emitted by road transport to 0 percent.
For the purpose of freight transport, electrical vehicles are still in the developmental phase. In the Netherlands, the road constructor KWS has developed the very first electric truck. The organisation wants to use the electric truck in its projects to transport bulked goods and materials, such as sand and stone. There are also plenty of opportunities for the infrastructure sector to reduce carbon emissions by making use of electric machinery during construction processes. In this article SKAO describes the different opportunities for electrification in the construction sector.
Other opportunities that lead to carbon reduction in the infrastructure sector include alternative fuels such as biodiesel, biogas and LNG (Liquified Natural Gas), CNG (Compressed Natural Gas) and hybrids. An example of biodiesel that is now widely used is HVO (Hydrotreated Vegetable Oil). This biofuel consists of plant based oils, such as used frying oil, and leads to a carbon emission reduction of 17 percent per year.
The largest amount of carbon emissions resulting from steel is caused during the production phase. The production of steel takes up to 70 percent of the total amount of CO2 emissions caused by steel, from production to usage. Little is known about the end-of-life phase of steel, researchers claim. It is however known that almost all steel in the construction sector is being reused as a component of a new construction, for example as a beam or pillar. In other instances, old steel is reused by melting the composition to create new steel.
Innovation and circularity
In order for the steel industry to cut back as much carbon emissions as possible, it needs to invest in new production methods. A practical example is shown by Tata Steel, that is currently working on new sustainable technology to reduce 50 percent of carbon emissions during the steel production phase.
Are you working on innovations that lead to CO2 reduction and/or circularity to contribute to a climate neutral infrastructure sector? We are curious to find out! Please contact us via [email protected] to tell us all about it.