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As India stands at the cusp of a building boom, retrofitting existing buildings to make them more energy efficient would go a long way to curb carbon emissions

Certain sections of Rashtrapati Bhawan has been made more energy efficient through upgrades.

It is estimated that two-thirds of the commercial and high-rise residential buildings that India will require in 2030 are yet to be built. With the emerging economy being at the beginning of this construction boom and addressing challenges of power outages, energy access and carbon emissions, improving energy efficiency in these buildings is one of the easiest methods to check carbon emissions.

While various states have come up with green building codes and there is a lot of focus on new buildings to go green through better energy efficiency, water conservation and sourcing energy from renewables, existing buildings often get left out of the discourse on green buildings.

This was one of the themes taken up in the recent ninth Griha Summit that saw a congregation of national and international architects, policymakers, developers, think tanks, ministers and government officials for knowledge sharing in the field of construction and building industry.

Retrofitting old buildings

Though it is a lot easier to build an environment friendly building, the question of retrofitting cannot be ignored because existing buildings consume 40% of the total energy globally. In India, they are responsible for using 30% of the country’s total power output, with their use of electrical appliances, lighting, refrigeration and water heating and air conditioning units.

“We are building 10,000 square metres of space every minute globally. It is like adding a city like Paris in every four days.  In India, 1,000 square metres are being built every minute and existing buildings consume energy at a significant rate. It can be improved through hardware intervention, software intervention and humanware intervention,” said Santosh Kumar Thakur, General Manager, Energy Efficiency Services Limited (EESL).

By humanware intervention, Thakur means the consumption habits and patterns of the occupants. Experts said that without the right behaviour, training and sensitisation, even a new building with a star energy rating could perform poorly.

According to an analysis by consultancy firm McKinsey & Company, India can save USD 42 billion every year just by reducing energy wastage in buildings. But there are various challenges when it comes to retrofitting existing buildings, which usually have old equipment and infrastructure and inadequate operation resources that are insufficient for futuristic needs.


First and foremost, the retrofitting plan requires a lot of customisation, which increases the cost, as changing the existing structure is often not feasible. “We even have to design room-wise. What is compatible for one room is not compatible for another. Plus, there are employees already working in the building so there are constraints on work hours. At many places we are told to carry out work in the night when the office is shut, which is not always possible,” said Akash Jain, director of Alien Energy Private Limited, who has been working on sustainable business models including buildings.

Other major challenges include non-availability of data, especially the power consumed by individual components in an old building, rather than just the total power bill.

“Forty per cent of the power consumption in a building is due to the HVAC (heating, ventilation and air conditioning) unit and 45% of that is due to chillers. The air conditioning has three components — the chiller, pumps and cooling tower — and all equipment will have different performance curves.  A pump at an 80% efficiency level or a load level would give a different efficiency, a cooling tower at the same time can give a different efficiency, a chiller maybe requires to operate 50%. So, how do these three components talk to each other? That’s the critical thing and that’s where the technologies are evolved. There are algorithm-based software that can make inputs of all the curves of the components and then they give you the best efficiency that a system can give and that’s where we clearly see tech evolving,” said Arun Bhatia, Managing Director, UTC Climate, Control and Security, a global provider of building technologies.

This becomes challenging in a building where power consumption data are not available at each point. But many of these challenges can be overcome, and it does provide a huge opportunity. Experts say that even if the investment is high, there are several low hanging fruits that can be utilised and the return on investments period is less than three years. It can help make huge power and energy savings.

Low-hanging fruit

One of the low-hanging fruits is to install super-efficient appliances like superfans, super-ACs etc., and targeting especially the heating and cooling systems since they consume 40% of the energy. Just focusing on the peak load can make a lot of difference. A building is normally designed for peak load but structures like hotels and hospitals have a lot of variable load, as there is constant change in influx of visitors. So, such a building becomes highly inefficient. Making a building compatible with variable loads can help reap huge energy savings. Even replacing normal bulbs by LEDs can make a big difference, something that EESL has been doing in a big way.

“The main problem is the budget. Often the existing buildings don’t have sufficient budget to retrofit the whole building. So it normally happens in parts, like a floor or a section. But what we are offering now is ESCO (Energy Services Company) model which has a high uptake and we have managed to bring down the cost of LEDs as well,” said Thakur.

Under the ESCO model, an energy company invests money to retrofit the whole building and in return the building owner pays back according to the energy savings that happen subsequently. So, it becomes a win-win situation where the owner is not required to make a big investment and the whole building becomes energy efficient in one go.

Due to the ESCO model, EESL – that had just 20 projects till last year – has now signed up 4,000 existing buildings that are slated to become energy efficient by 2020. Alien Energy Private Limited has completed 500 projects under the ESCO model with good returns.

For example, Taj Palace hotel in Chanakyapuri, New Delhi, – already a star rated building – has managed to save 100,000 more units of power, valued at INR 9 million every year, just by retrofitting chillers. Through a simple street lighting project under ESCO model with the Haryana government, Alien Energy is generating revenue of over INR 7 million for itself and over INR 2 million for the state government every year just through power savings. Even government buildings like Rashtrapati Bhawan have become more energy efficient through upgrades.

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