Shift to net-zero buildings is not only cheap now, but viable too; India slowly finding solutions as well | India News

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NEW DELHI: Cheap technology and sufficient skills already exist worldwide to achieve net-zero energy buildings – those that produce enough renewable energy to meet their annual energy demands – at costs in the range of traditional building projects, a study published recently in the Annual Review of Environment and Resources has found.
The study examined low and ultra-low energy buildings along with policies internationally and found that with the right strategy, materials and appliances used, change can often be achieved quickly, often in a matter of months.
For instance, Brussels transformed their buildings from among the lowest performing to the highest performing in all of Europe in just seven years, using a combination of voluntary measures to support and encourage industry leaders to innovate and demonstrate what was possible prior to requiring that level of performance through regulation.
The study also found that since the project spend related to energy efficiency was low, the cost of sustainable buildings could match or even be less than those constructed through traditional methods. For instance, the city of Vancouver anticipated a modest increase in construction costs as a result of increased building code performance requirements but instead experienced a cost decrease of 1% in the long run.
“The sustainable cooling of buildings is a major challenge,” said Radhika Khosla, study co-author and Senior Researcher at the Smith School of Enterprise and the Environment, University of Oxford. “In a warm climate, building energy use will go up even if cooling is as efficient as possible. Rising affluence, space and comfort needs are set to dramatically increase energy demand – with corresponding increases in greenhouse gas emissions. However, there are solutions: for example, shading and wind-channelling designs to block the sun and allow for natural ventilation in high-rises,” said Khosla.
While the study highlighted the ease with which several cities have begun transitioning to sustainable housing, it highlights several challenges too – namely the technological difficulties in making high-rise commercial buildings in hot and humid climates efficient enough at a low cost, while historic heritage buildings that need to be retrofitted pose an equal challenge. It stated that deep retrofits were also costly in the short term and although they may cost less over time, innovative financing is often required upfront.
The share of heating or cooling in the total building energy use varies from 18% to 73%, depending on the type of buildings (residential or commercial), the climate, and the region of the world (developing countries versus developed ones). The lowest share (18%) is for commercial buildings in north Africa and the middle east, while the highest (73%) was found in central Asia.
The total energy consumption in BRIC (Brazil, Russia, India, and China) countries has already surpassed that of developed countries, and the continuous increase of the building stock predicts the potential continuation in the increase of energy consumption in the countries.
Architect Ashok B Lall, who has worked on several green buildings, says achieving net-zero is possible in India through a fairly cost-efficient approach, however the European model which involves isolating the building completely from the outside by using several layers of insulation was ill-suited to India’s climate. Lall instead advises using the right combination of shading, protection from the sun in the form of roofs outside windows and ceiling fans to reduce dependence on air conditioners. “It has been established by very sound research that a combination of shading, protection from the sun and air movement over your skin (ceiling fans) enables you to feel comfortable at temperatures in the dry seasons up to 32 degrees centigrade and in a humid season up to 27 degrees centigrade. This, combined with natural ventilation whenever possible ensures you reduce your demand for air-conditioning and you can then supplement the remaining energy by using solar panels to move towards net-zero,” said Lall.
He also states the use of a ceiling fan with an air conditioner allows the body to feel cooler by 2-3 degrees, allowing the air conditioner to run at a higher temperature, thus reducing its energy demand. While buildings across NCR are slowly adapting this approach, Lall says more can be done, pointing towards Unnati – a green building built in Greater Noida recently for the company Gainwell, which has been built on a zero emission, zero waste and zero water discharge model with its energy demand significantly supported by solar energy. The LEED platinum building has shaded windows, reduced artificial lighting, controlled daylighting, a rooftop garden and insulated walls among others.
Delhi has ample opportunities to go green
In terms of shifting to net-zero, or making a building largely reliant on renewable energy, Delhi has a few models which have emerged over the last decade. The Indira Paryavaran Bhawan in central Delhi – housing the ministry of Environment, Forest and Climate Change (MoEFCC) is perhaps the best example, also being India’s first net-zero building. Utilising its rooftop to capture solar energy, the building also has been designed architecturally keeping the best practices in mind, while using adequate insulation and materials that will reduce energy consumption. Inside, the appliances chosen are also high on the energy-saving quotient.
In terms of large infrastructure, the Delhi airport too has been working towards a similar goal, receiving the ‘Excellent Energy Efficient Unit’ award this year for the third successive year running at the National Awards for Excellence in Energy Management by CII-Green Business Centre.
To make key energy savings and reduce emissions, the Delhi airport has adapted climate change strategies and has been making use of solar energy, alongside strategies like using natural sunlight better, utilisation of UV lamps in re-circulated air handling units and oxygen optimizers among other solutions.
Saswati Chetia, Senior Project Officer at Greentech Knowledge Solutions (P) and an expert on sustainable building designs, says while solar panels are not the only solution to achieve net-zero buildings, it still remains a resource that India is richly blessed with.
“Plus, with all the solar technologies available in the market and the Government of India’s policies, it becomes the most attractive and economical option of renewable energy. Buildings like the office of the Ministry of Environment and Forests in Delhi (Indira Paryavaran Bhawan) is the 1st net-zero building in India. Similarly, the HAREDA demo centre in Gurgaon is also a fine example of what can be done and what needs to be done to achieve net-zero,” said Chetia.
She believes while the concept to shift to net-zero remains the same – reducing the energy demand by having a good building design and efficient appliances, India cannot rely on western concepts due to different climates.
“Western countries with a usually colder climate will design their buildings to get in more sunlight to heat their building naturally and thus save on the heating requirement. We, in India, have to do the opposite. We will have to design buildings to avoid the sun’s heat most of the time (while still allowing enough daylight). So we have to ensure that we do not use a lot of glass in our buildings and wherever we do, we have to ensure that they are absolutely well shaded. Heat from the walls and roof should also be optimised. Roofs should definitely be insulated and have a reflective finish. Walls should also have moderate to good insulative properties- This means that external walls made only of concrete will be a no-no unless they have added insulation,” Chetia added.
In terms of switching to solar rooftop panels, Delhi is also realising the benefits it can offer in the long term. In 2018, a number of CGHS societies in Dwarka were provided solar panels under the ‘Solar City Initiative – Solarise Dwarka’ scheme by BSES, in collaboration with TERI and Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ India) under the Indo-German solar partnership project. Now, these societies are saving lakhs annually.
Initially, seven societies were chosen for the project and they reported cumulative savings of 6.5 lakh electricity units and Rs 32 lakh annually. Now, several other societies have also joined in.
Generally, a feasibility test is carried out to assess the solar rooftop potential of a society, based on which the capacity of the solar panels are suggested. Based on the energy being generated and provided back to the grid, each household can reap its benefit through solar rooftop net-metering connections.
Global learnings:
· A University of Sevilla study in 2018 says operating buildings based on adaptive thermal comfort can lead to 27.5percent energy savings.
· A study in Morocco found that optimized overhangs (chajjas) reduce the cooling demand by 4.1% for Casablanca’s mediterranean climate, and improved the thermal comfort.
· Another study in Singapore says “Relative to a typical room design condition of 24°C with a conventional air-conditioning system, a Dedicated Outdoor Air System with ceiling fans achieved a 25.8% reduction in annual energy consumption when the room temperature was raised by 3°C but compensated by increased air movement.”
(The story is being published as part of CMS-BEEP Media Fellowship Program)



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