How India’s Progress Towards Green Buildings Can Be Hastened

By 2030, more than half of India’s population will be living in cities. This will create a huge demand for housing and infrastructure in urban areas.

India’s rapid urbanisation is driving unprecedented demand for construction, making sustainable building materials essential for reducing carbon emissions.

India’s Energy Security Scenarios (IESS) 2047 report projects an addition of nearly 40 billion square meters to residential and commercial building spaces in the next two decades. This means that 70 percent of the building infrastructure needed for 2047 is yet to be constructed.

The building sector is one of the major contributors to global carbon emissions. Some estimates point to nearly half of such emissions, called embodied carbon emissions, originating from material extraction, construction, maintenance and disposal. The other half comes from the operational energy used over the building’s lifespan.

This ratio of embodied emissions can be higher in the case of conventional non-air-conditioned buildings because operational energy consumption is lower in India compared to developed nations as most buildings are not airconditioned.

There has been considerable focus on improving the operational efficiencies of buildings since this is seen as a low-hanging fruit.

Energy Conservation Building codes first introduced in 2007 provided minimum energy performance standards for commercial buildings. For residential buildings, Eco Niwas Samhita codes were introduced by the Bureau of Energy Efficiency in 2018.

Choice of materials

In building design, the choice of materials plays a major role in operational energy usage and the embodied energy of the building material.

For example, compared to a conventional building, the contribution of energy savings in the 5-star green-rated project of the Centre for Environmental Science & Engineering building at the Indian Institute of Technology, Kanpur showed that the contribution of the building envelope (including the roof, walls, doors, windows, and foundation) in improving operational efficiency can be up to 15 percent of the total energy consumed.

Embodied energy, meaning the energy consumed by all of the processes associated with the production of a building, which is locked in at the time of construction, can often equal the total operational energy of a building (assuming a lifespan of 30-to-50 years). The embodied energy of cement and reinforcement steel in a conventional Indian two-storied house can be around 69 percent of the total embodied energy of the building.

In India, almost 70 percent of steel and cement produced is used in the building sector. This makes the building sector the prime target for addressing the Nationally Determined Contributions committed by India to reduce carbon emissions internationally.

Both the cement and steel industries have done well in reducing their specific energy consumption through the government’s Perform and Trade (PAT) scheme.

The PAT scheme has now transitioned into the Carbon Credit Trading Scheme (CCTS), given the target of meeting net zero target 2070 by the government.

To meet these targets, the cement industry is pursuing initiatives to improve the sector’s environmental performance. These include improvement in cement design, use of less material, switching manufacturing processes, decarbonising heating and carbon capture and storage.

Cement substitutes such as limestone calcined clay cement, geopolymer concrete and composite cement developed by the industry have emission reduction potentials of 30 percent, 56 percent and 80 percent, respectively.

Many Indian steel industries have also increased the production of green steel or steel produced using sustainable methods that reduce carbon emissions.

After steel and cement, it is the wall infill materials that have a significant impact on carbon content. Some widely used options are burnt clay bricks, fly ash bricks, concrete blocks, hollow concrete blocks and Autoclaved Aerated Concrete (AAC) blocks, among others.

Choosing an infill material which has a higher recycled material content helps reduce the embodied carbon. Materials with better thermophysical properties such as thermal conductance makes building more efficient in operational energy.

Design interventions

Another approach to decarbonisation is through structural design interventions. Voided concrete slab technology and bubble deck technology can reduce the demand for reinforced cement concrete (RCC) by 25-30 percent.

Confined masonry (where masonry walls bear the building’s load, reinforced with horizontal and vertical reinforced concrete elements such as tie beams and tie columns for added strength and stability) can reduce the weight and volume of RCC demand by 38 percent.

Architectural design can also allow for modularity and promote the use of lightweight construction. This reduces the weight, volume and time required for construction.

While the industry is aligned with the goals being set by the government, the uptake of these construction materials is linked to market acceptability.

One of the bottlenecks for mainstreaming sustainable building materials is the non-availability of reliable data on the environmental aspects of building materials and the lack of testing facilities.

Research organisations have worked with government agencies and industry to bring credible data on building materials and their environmental performance to the public domain.

However, there is a long way to go in strengthening the availability of data on sustainable building materials.

Widespread use of alternative materials with a higher sustainability quotient could have a significant impact on mitigating emissions even before the building becomes operational — providing accelerated benefits for climate mitigation at national level.

Government procurement policies in the public sector can play a significant role in mainstreaming sustainable materials by setting standards, aligning building byelaws with alternative sustainable building materials applications, streamlining supply chains, disseminating information and building capacity amongst professionals and construction workers.

(Published under Creative Commons by 360info™. Read the original article here)