A huge cantilevered roof, lined with solar panels and situated on top of a government building on Delhi’s Lodhi Road, is visually striking. This is Atal Akshaya Urja Bhawan, the new headquarters of the Union ministry of new and renewable energy (MNRE). Even though the roof is prominent, it is the thinking behind the building that makes a louder, and more progressive, statement about sustainability. Designed to be a “net energy positive” building, or one that generates more energy than it consumes, the 4.10 lakh sq.ft Atal Akshaya Urja Bhawan illustrates three important principles of sustainable architecture.
The first principle is that constructing a green building is all about strategic intent. “Green buildings are not an afterthought. They are by design,” says Shaon Sikta Sengupta, the Delhi-based director of Edifice Consultants, one of India’s best known architecture firms and the practice engaged by the MNRE to design and construct the headquarters. The brief from the ministry was clear from the start, to build a net zero building. An international design competition was held in November 2015 and a jury composed of architecture professionals and government officials was convened to judge entries. Edifice’s bid to construct a net positive (not just net zero) building, as well as its past experience with sustainable architecture in other parts of the country, including office buildings for Monte Carlo in Ahmedabad, Amara Raja Batteries in Tamil Nadu and Infosys in Indore, led it to be awarded the project. The project has nine floors, including the ground level, and three basements.
The building can seat 750 office workers, and cost ₹266 crore. The construction at the site began in June 2018, and was completed in April 2022. It is now fully occupied.
The second principle is that there is no one silver bullet in a green building. I believe designing a green building is a bit like trying to lose weight. Everything counts, reducing the consumption of energy, reducing the heat going into the building and trying to maximize the scope for energy generation—just like sustainable weight loss is not based on fad diets, but needs a comprehensive plan of working out, eating right and getting enough sleep.
At Atal Akshaya Urja Bhawan, energy consumption has been reduced through a number of strategies, including building orientation, daylighting strategy, choice of materials, use of passive cooling techniques and investment in energy-efficient equipment (see box). This energy conservation approach is then complemented by energy generation strategies such as the solar panel-lined roof and wall. Tremendous savings in energy are predicted. “The Energy Performance Index measures consumption in the form of a kilowatt hour (kWh) h/square metre/ per annum. We have a benchmark number based on audited data of buildings operating in various climate zones pan India, which is 70. Atal Akshaya Urja Bhawan is expected to oper- ate at around 45-50,” says Ankit Bhalla, manager of GRIHA Council, India’s homegrown green building rating system.
When pitching the project, Edifice calculated that the building would generate 1400 mega- watt-hour per year and consume 1200 mega- watt-hour per year. Its electricity bills indicate it is on track to deliver these savings.
Reduced energy consumption has not compromised human comfort.
“The good thing between conventional cooling and radiant cooling is that with radiant cooling you feel comfortable even at a higher temperature, because all the surfaces, such as the ceiling and the floor, are getting cold, and coolness is radiated all around, rather than a blast of cold air just being targeted at one spot,” says Sengupta. The building has a hybrid system, she adds, with “the heavy lifting being done through radiant cooling, and additional comfort through air-conditioning.”
This design strategy also relies on a progressive mindset by clients and architects, to find a solution that is suited for the particular site location, climactic conditions, stature of the client and its net zero briefs. For example, even though glass is associated with contemporary architecture and the client initially wanted a headquarters with a “modern outlook”, glass was used only “sparingly and intelligently” to avoid unnecessary heat gain, says Sengupta.
Glass was instead combined with Dholpur stone, to remain contextual to Delhi’s institutional architecture where public institutions are often constructed in sandstone.
Finally, the building illustrates that it is possible to construct a net energy-positive building in the middle of a city, on a compact plot of 2.76 acres, with a narrow sliver of land.
“The net zero concept typically comes up with large campuses, which have many acres of land where one can construct extensive solar farms, but how many such large campuses are there?” Sengupta asks. Cantilevered roofs, solar panel-lined walls and radiant cooling—one would expect nothing less from a ministry dedicated to new and renewable energy.
Once again, it highlights that green buildings are constrained only by imagination and invention and can be replicated across India. I would be surprised, though, if the average real estate developer made the same design leap for a corporate office, given our propensity for glass structures and limited willingness to look at sustainability with a strategic lens. Construct- ing a green building requires strategic intent as much as technical know-how.
Cantilevered roof with 60,000sq.ft of solar panels and a solar panel-lined southern façade
Blocking off west sun by creating a brick wall with recessed and shaded windows for diffused sunlight
Reducing heat ingress
Radiant cooling by embedding copper pipes in floors and false ceiling
Lower surface temperatures without compromising on comfort
Reducing air-conditioning footprint in certain parts of the building
Reduced energy consumption
Insulation against heat and cold
Energy efficient equipment and materials such as high efficiency glass, chillers, LED lighting
Reduced energy consumption
Recycling waste water
Aparna Piramal Raje meets heads of organisations every month to investigate the connections between their workspace design and working styles.