Mumbai: The building sector accounts for a quarter of global energy-related emissions and 30% of energy consumption. In India, the sector accounts for one-fifth of emissions and 33% of its energy consumption. To meet the goals of the Paris agreement, under which countries have committed to take actions to limit the global temperature rise to below 2°C by 2100, all buildings must have net-zero carbon emissions by 2050. However, the buildings and construction sector remains off-track to achieve decarbonisation by 2050.

By 2030, India’s building stock is predicted to rise four-fold. With rising temperatures, including night-time temperatures, and erratic rainfall, cooling needs are expected to surge, leading to an eightfold rise in energy consumption of buildings by 2050.

India is now the third-largest global emitter, emitting a net 2.9 gigatons of carbon-dioxide equivalent (GtCO2e) every year as of 2019, despite having low per capita emissions (1.8 tons). It has been responsible for more than 10% of the increase in global energy demand since 2000. Over 80% of India’s energy needs are met by three fuels--coal, oil and biomass.

More sustainable construction and efficient use can reduce the use of energy by 42%, greenhouse emissions by 35%, and the extraction of material by more than 50%. Energy-efficient buildings, which have a lower carbon footprint during construction and also lower energy needs during operation, are imperative for India to achieve its own net-zero goals by 2070. But higher costs of such construction, low awareness and poor planning hinder this progress, experts say.

Changing climate and the need for sustainable building design

This year, India had its warmest February and driest and warmest August since 1901, while the nights in July and August were the second warmest since 1901. Warm nights increase heat stress on the body, and can worsen heat-related morbidity and mortality, IndiaSpend reported in May 2023. This changing climate can impact indoor energy use, with increased cooling needs, and therefore, the buildings sector has high mitigation potential.

Climate-resilient buildings will not only reduce energy demand, but can help meet current energy demands, says Ameya Pimpalkhare, a sustainable energy engineer and a Growth Officer at Datachamps, a data analytics firm working on projects related to sustainable growth. A 2016 study by researchers from IIT Bombay and New Delhi-based think tank Observer Research Foundation (ORF), ‘Estimating rooftop potential of Greater Mumbai’, published in November 2016, of which Pimpalkhare is a co-author, shows that Greater Mumbai’s average power demand is 3 GW while the metropolis has a rooftop solar potential of 1.72 GW.

“If this rooftop potential is utilised, close to half of the electricity can be saved and this could be supplied in the nearby areas where 24x7 power supply isn’t available,” he says. “Through sustainable design, construction, and operations, we can make buildings that are climate-resilient, consume less water, use energy optimally, conserve natural resources, and generate less waste.”

“As of today, we are not designing for climate resilience. We are designing and constructing buildings for meeting immediate housing needs of the people,” says Sumedha Malaviya, building decarbonisation policy researcher at World Resources Institute (WRI) India, a New Delhi-based nonprofit.

Buildings constructed today emit two types of energies: embodied energy and operational energy. The embodied energy is associated with the design, materials sourcing, and building construction and demolition process. It also includes energy spent or carbon created during the manufacturing of building materials such as steel, cement, or red brick, as well as the transportation of this material to the construction site. Operational energy refers to the carbon emitted or energy released throughout the lifetime of the building--it comes from energy, cooling or heating, lighting, and so on.

The changing climate also impacts building structures (such as impacts of environmental catastrophes such as floods, landslides, storms, and excess snow load), building construction (decay of fastening and water supply systems), building material properties (diminished performance of frost-resistance, UV-resistance, and insulation due to material decay) etc. Picking the most suitable materials is thus important both to building safety and to reducing ‘embodied energy’.

Operational emissions in India account for 60% of the total emissions of buildings, compared to 76% globally. This is due to India’s lower appliance penetration and the prominent use of emissions-intensive building materials.

Architectural design plays a significant role in reducing embodied energy, says Jit Kumar Gupta, an architect and former chairperson of the Chandigarh chapter of the Indian Green Building Council (IGBC), a certification body promoting green building practices in India. Traditionally, climate was central to the construction practices of India. Now, glass is popular and people prefer it for natural light and aesthetics. But glass also traps heat--especially when installed on the west side--leading to excess power consumption to keep the building cooler, he explains. Architects should consider factors such as sun movement, orientation, wind direction etc. when designing buildings, so they are energy-efficient, he adds.

The case of Jodhpur’s buildings

Old blue-coloured houses at Brahmpuri, Jodhpur. Photo from August 2022.

Let’s take the example of the desert city Jodhpur, called the ‘blue-city’ owing to its light-blue painted houses. Thick walls and stone masonry are being replaced, as knowledge and values associated with ancient construction methods and structures gives way to modern methods. The blue colour in the construction, a mixture of copper sulphate and limestone, was being used to protect buildings from excessive heat, besides being perceived as soothing. The culture of painting houses with blue colour in Jodhpur has different origin theories, one of which is thermal comfort, says Abhiyant Tiwari, Lead, Health & Climate Resilience at the Natural Resources Defense Council (NRDC) India.

People are using reflective paints on new buildings, to reduce heat, says Pratap Gaur, a 42-year-old street vendor. Pratap said using coolers is a common practice now as an adaptation technique due to excessive heat in Jodhpur. This is leading to higher energy demands, which used to be low with traditional construction in Jodhpur.

Materials play an important role in cool roof applications, Tiwari explains, adding that high solar reflective cool roof paint helps in reflecting the solar energy and radiating the absorbed heat from the surface of the roof. “So, rather than heat getting transferred into the house below, it gets emitted back from the rooftop, and helps in creating thermal comfort indoors.”

“Due to the architecture of the houses here, the air remains cool, and we often sit outside during hot days,” says Namrata Kumawat, a 38-year-old home-maker, while showing her blue painted two-storey house near Tapi Bawdi in Jodhpur.

Gupta, the architect, says, “Courtyards played a significant role in maintaining a comfortable indoor environment. Balconies were strategically placed to act as a buffer, absorbing and dispersing excess heat before it reached the interior of the house. To enable proper ventilation while preserving privacy, they incorporated beautifully crafted jaalis (intricate lattice screens), allowing clear views both inside and outside.”

Renovated construction as a part of Jodhpur’s Toorji’s Stepwell regeneration project with stone tiles. Photo from August 2022

Building with older construction components, like Jharokas or enclosed balconies. Photo from August 2022.

These intricate architectural elements facilitated the circulation of fresh air and allowed ample natural light to filter through, enhancing the living experience. Moreover, Jharokhas, or overhanging enclosed balconies, played a crucial role in directing the airflow inside the building. As air entered through these Jharokhas, its velocity increased, promoting better ventilation and cooling.

“For making cities sustainable, in addition to designing green buildings, city planners should also give due consideration to the orientation while preparing the layout of any area for making sustainability an integral and essential element of planning, so as to enable architects to design green buildings,” says Gupta.

The choice of construction materials was also well thought-out. Special stones like red sandstone could absorb heat efficiently and gradually transfer it to the building, ensuring a more stable and comfortable indoor temperature.

“Courtyards (of varying sizes depending on climatic region), high thermal mass for wall insulation, and optimum window sizes were commonly observed features of dwellings,” says Pooja Gangwar of WRI India, an architect supporting building sector decarbonisation and sustainable cooling. “However, with the cultural influence of colonial bungalows, outdoor lawns became a preference over indoor courtyards. The rise in population, land politics, and space constraints resulted in many outdoor spaces being consumed in building more structures and changes in architectural designs.”

Contrast of new (left) and old construction (right) at Brahmapuri, Jodhpur. Photo from August 2022.

New construction of cement, with stone tile façade, Jalori Gate, Jodhpur. Photo from August 2022

Newly constructed houses with cement and coolers, near Baiji ka Talab, Jodhpur. Photo from August 2022.

The introduction of new building materials has also created an issue, especially cement concrete. India’s cement production is expected to rise from an estimated 500 million tonnes in 2020 to 800 million tonnes by 2030. While concrete is often considered a versatile solution and is resilient to natural hazards because of its strength, it needs a lot of water and absorbs a lot of heat.

Gaps in existing building codes and regulations

India is one of the countries with the lowest access to cooling, and India’s demand for ‘space cooling’ is expected to rise rapidly.

In August 2021, the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) warned that the Indian subcontinent would suffer more frequent and intense heat waves over the coming decade. Heat waves across India were likely to last 25 times longer by 2036-65 if carbon emissions remain high, as in the IPCC’s worst case emission scenario.

Approximately 8% of households have air-conditioners (ACs), and this is expected to rise to 40% by 2037-38. According to the International Energy Agency (IEA), refrigeration and air conditioning (RAC) causes 10% of global CO2 emissions.

The National Disaster Management Authority (NDMA) and the India Meteorological Department (IMD) are working with states to create heat action plans (HAPs) as part of preparedness, information-sharing, and response coordination to reduce the health impacts of extreme heat on vulnerable populations. According to the NDMA, in the last five years, 17 heat-wave prone states and more than 120 districts/cities from 14 states have prepared their HAPs.

The Centre for Policy Research, a New-Delhi based think-tank, analysed 37 HAPs at various levels, of which only two had conducted vulnerability assessments. Jodhpur’s plan, released in April 2023, mapped vulnerability and derived a risk score for each of its wards. It also proposes cool roofs and blue walls as long-term strategies in grappling with heat.

The India Cooling Action Plan (ICAP), released in 2019, has seven broad recommendations including an accelerated reduction of cooling load through fast-tracked implementation of building energy codes, adoption of thermal comfort standards and targeted programmes to enable thermal comfort for affordable housing. In March 2022, the government presented the progress under the plan in the Lok Sabha. Towards promoting passive cooling in buildings, the Bureau of Energy Efficiency has brought out the Energy Conservation Building Code (ECBC) for all large commercial (non-residential) buildings and Eco-Niwas Samhita (ECBC-R) for residential buildings. Building codes are vital to addressing building sector emissions.

ECBC-R sets standards for building roofs, walls and fenestration (openings such as windows, doors, vents) to limit heat gains (for cooling-dominated climates) and to limit heat loss (for heating-dominated climates), and for ensuring adequate natural ventilation and daylighting potential. However, the code is currently in the ‘voluntary’ stage of adoption.

As of 2019, 11 states and only a few cities in India, like Ludhiana, Gwalior, Udaipur, Visakhapatnam, Hyderabad etc. had included ECBC in their building bylaws. An ECBC Cell has been incorporated in 31 states.

“There are no state cooling action plans on the lines of the ICAP. It is up to the states to adopt, notify, and implement building energy codes for the new construction. For the existing buildings, the ICAP recommends adoption of energy-efficient appliances or cooling equipment like fans, air conditioners, etc.,” says Malaviya of WRI India.

Apart from ECBC-R, India has developed its energy rating systems which covers various aspects of the building including design elements that impact energy use, sustainability, human comfort etc. These include GRIHA (Green Rating for Integrated Habitat Assessment) set-up by the Ministry of New & Renewable energy in 2007, and the most recently developed Green & Eco-friendly movement (GEM) sustainability rating by ASSOCHAM. The Green Business Certification Inc., a private organisation, also provides certification in India under the global Leadership in Energy and Environmental Design (LEED) green building rating system.

“These codes consider only the operational emissions of a building, the remaining 40% is embodied emissions, which is unaccounted for in the existing versions of the building codes,” says Gupta, the architect.

Most of the building stock of 2050 is yet to be built in India, according to a report by the Rocky Mountain Institute, and as we said, embodied emissions account for 40% of India’s building emissions compared to 24% globally. Hence, regulating these embodied emissions would be crucial for decarbonising the building sector and contributing to India’s net-zero target. The improvement of the sustainability of construction through more efficient construction and use of buildings would decrease the use of energy by 42%, greenhouse emissions by 35%, and the extraction of material by more than 50%.

Rather than having multiple rating systems, to rationalise the process of green rating of buildings, there is a need to have a single national rating standard, which should be made an integral part of building bye-laws integrated with development plans at the city level, says Gupta. This has also been reiterated in ICAP by adopting ECBC through city level action plans.

High costs limit widespread adoption

There is a noticeable shift among present-day consumers to lead a sustainable lifestyle, but cost economics of energy-efficient buildings needs to be addressed, says Shailesh Kumar Agrawal, Executive Director, Building materials & Technologies Promotion council (BMTPC), in a special newsletter of BMTPC. BMTPC is a council set-up by the Ministry of Housing and Urban Affairs (MoHUA) for helping in bridging the gap between research and development and large scale application of new building material technologies.

According to IGBC, the cost of green buildings in India is reducing due to better access to new technologies and materials. In 2003, for a platinum-rated building of CII-Godrej GBC, Hyderabad with a built-up area of 20,000 sq.ft., there was additional cost of 18% to the conventional building and pay back of seven years. However, in 2010, for a platinum-rated building of Suzlon Earth, Pune with built-up area of 800,000 sq.ft., the additional cost has been reduced to 2% and will be paid back in two years, Gupta told us.

One has to hire an extra team of green consultants for green rating which entails fees for the rating agency, fees for consultants and incremental costs toward including green features which might be mandated by the rating agency.

Additional cost is also incurred to get green certifications. For projects with less than 2,500 sq m built-up area, GRIHA has introduced SVAGRIHA Precertification, a design-cum-rating tool to assess the building, which costs Rs 30,000. However, this cost will vary based on the built-up area, new construction or existing building, type of use of building etc. For low-income households, to reduce the operational costs and GHG emissions, there is a certification of “GRIHA for Affordable Housing" at a cost of Rs 2.5 lakh for 10,000 sq.m., with additional area charged at Rs 3.74 per square metre.

Further, there is a lack of a large skilled work-force to conduct life-cycle assessment studies, and to work with low-carbon materials and techniques. Hence, investments towards capacity building for energy-efficient building materials and construction techniques is essential.

The slow pace of R&D and lack of investment from the government particularly in the fields of architecture and planning also restricts the introduction of new innovative materials. “There is a disconnect between educational institutes and the industry,” says Pimpalkhare of ORF. “While some institutes conduct groundbreaking research, there is a failure to bridge the gap and translate these findings into practical applications. Research parks can serve as a facilitator between institutes and industries where industry problems could be resolved with innovative solutions through collaboration.”

To encourage bigger players to switch to energy-efficient buildings, incentives for energy-efficient practices--such as property tax rebates or tax reductions--and penalties for non-compliance could be introduced, says Pimpalkhare.

To understand the establishment of a national rating system for buildings, a net-zero road map for energy-efficient buildings, and ICAP implementation at the state level, IndiaSpend wrote to Naresh Pal Gangwar, joint secretary and Manoj Joshi, secretary, at MoHUA, and to Leena Nandan, secretary in the environment ministry, in August and September 2023. We will update the story when we receive a response.

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