The biggest challenge for contractors and designers is to have the necessary skills and know-how on how to reduce carbon emissions to make their projects sustainable.
Jacobs - Sandeep Singh Nirmal, Senior Tunnel Engineer
All the stakeholders including clients, contractors, designers, and end-users have to come together to reduce the overall carbon emission in the construction industry. Design plays an important role as it can drive innovations and propose changes to construction processes at a very early stage of the project.
The first step is to determine whether the project really needs to be built or should the existing structure be refurbished/modernized to provide the same services. The second step is to decide the scale and size of the project. Technology has changed the way we work in offices, so do we still need big offices and big buildings?
Designers need to specify what materials should be used and how much embodied carbon they have. The idea is to use minimum materials and materials that are environment friendly. Sustainable construction can be achieved by substituting materials with low carbon alternatives (such as use of SFRC, GGBS), improving design criteria for a better understanding of design processes, explore if we can build better alternatives, including sustainable construction and transportation practices, and to include cost-sustainability assessment of the project right from planning stages.
Bring focus on sustainable energy sources
I think for India there would be two different industries which are going to drive the change: First is public transportation, as 30% of our population lives in urban areas and need sustainable transportation systems. We need more metros and less personal vehicles on road. With space constraints in densely populated areas, going underground is a sustainable transportation solution.
The second is sustainable energy sources. India has a huge potential for hydropower and we need more tunnels to support these hydropower plants to generate the electricity.
Large amounts of concrete and cement are required for tunnel construction and therefore construction has a huge carbon footprint. So, conscious efforts are needed to reduce the carbon footprint of cement. We can substitute cement with GGBS or other low carbon materials.
Further, tunnel construction related carbon should also be related to the service life of tunnels (which is usually longer as compared to other structures) and has low maintenance cost, which makes them sustainable. For example, a tunnel has a greater life expectancy because of its durability when compared to a bridge. When you factor in the time and the cost incurred in repairs, rebuilding, or retrofitting a bridge, the tunnel would be less carbon intensive. There are various tunnels across the world that are over hundred years old and are still operating in railways and highways.
Waste management a major decarbonization tool
We need to find ways to reuse or reduce the resources that we use during construction. We need to improve the processes throughout the value chain. For example, for shotcreting, there is large rebound of aggregates and cement. If we do not use the right technique, these rebounds can be as high as 50%, which is a huge waste of materials and resources.
We need to improve techniques such as spraying of concrete, binding properties of concrete etc. in order to ensure a good shotcrete mix with minimum wastage. Another example could be tunnel construction generating a lot of muck during excavation. So, we need to have a robust plan at the early stage of the project for its reuse or disposal in nearby local settlements or industries.
There should be a pre-planned strategy on how to recycle or reuse the unused concrete and steel. We need to find ways to best utilize the concrete we are putting in for primary lining or for temporary construction, (example, for station boxes in an underground railway or underpass) to use its part strength with permanent structures for long-term use.
Policies, guidelines, incentives, and documentation of carbon footprint
I strongly believe that there should be policies, guidelines, and contract clauses that specify carbon expected to be produced by a project and how can it be reduced during various stages of execution, using innovative technologies and processes. There should be incentives for contractors and designers to bring innovations into their projects.
It is very important to have a tool where we can calculate the carbon associated with the project. In UK, for example, material manufacturers have to submit a statement on how much carbon is embodied in their product. This information is collected for materials to be used in a project to carry out carbon calculations. With this information, we can easily calculate all the carbon associated with a project, understand the source of the carbon, identify the source of wastages, and propose what could be improved.
This will help the clients to monitor carbon associated with the project. This will also motivate contractors and designers to evaluate their construction / design practices and understand possible ways to improve the same. The International Tunnelling Association, with which I’m associated, is in the process of developing a comprehensive sustainability indexing tool for underground projects which can be used by anyone in the future once it is published. The tool is being created for diverse applications across the globe and should be applicable to developing and developed countries as well.
Involvement of government, industry, and clients
India has numerous existing agencies, committees and organisations working for improvement of environment and reduction of carbon in the atmosphere. Some clients have already started integrating sustainable practices into project execution. With rapidly rising global temperatures and climate change, we need to bring innovative carbon reducing ideas and guidelines, which should be an integral part of project execution right from the planning stage. We need further collaboration of governments, industry, and clients who are building the projects in order to bring the ideas and the guidelines into the contracts, so that the contractors and the project designers are bound to follow them.
One of the competitive agencies is the Bureau of Indian Standards (BIS) which can create compulsory and measurable guidelines for embodied carbon in a project. Each industry in the field of construction – dealing with buildings, roads, railways, bridges, or tunnelling, have different ways of reducing their carbon emission. So, any such guideline from BIS can be used as a reference and clients can further include these ideas into their contracts and modify them to suit their specific requirements as per the project.
It is also important to have a statutorily enforced time specific goal for the construction industry to reduce its carbon. The industry shall be made aware of how much carbon they need to reduce in 10 years or in a given timeframe and enforce these rules to clients, manufacturers, suppliers, designers and contractors. It is important for these enforcements to come from the government, as we are a developing country, and clients, contractors and designers need financial support and investments to adopt sustainable practices. India’s focus is to create infrastructure and build more in less time and budget, but, generally, sustainable alternatives cost more. So, the government should support the industry with funds and incentives for undertaking innovations, research and developments.
As far as execution of these guidelines is concerned, the biggest challenge for contractors and designers is to have the necessary skills and know-how on how to reduce carbon emissions. They need resources, skilled people, money, and time to bring sustainability into their projects. If we want to create a sustainable world, we need both horizontal and vertical collaborations and make continuous informed decisions at each stage of the project to deliver in a sustainable manner.
This includes taking difficult decisions to prioritise decarbonisation and sustainability over factors such as profits and project completion time. We need to take small steps forward with every project to reduce carbon associated with it and improve the processes as we go along. Such efforts will see accumulated positive results in coming future and set an example for other projects to follow.