Converting CESC House into Green Building

About CESC House
CESC House is a head-quarter of CESC Ltd which provides electricity to the city of Kolkata. This 80 year old Heritage Building was built in year 1933.

There are Ground + 5 floors of office area. The total gross floor area is 72506 sft for office space area-mixed use application.

On an average, 540 nos full time employees occupies the building along with 300 nos supporting staff and 260 nos visitors.

The Air conditioning requirements for the entire building is catered from a centralized chiller plant system comprising 2 x 170 TR screw water-cooled chillers.

Energy Consumption Measures:

CESC House has seen its electricity consumption growing at a rate of 2% p.a. from 29 lacs kwh in 2006 to 33 lacs kwh in 2012

As a responsible corporate citizen, CESC is committed to promote energy savings to its 2.8 million consumers and all its peers.

Energy Saving in this building keeping its aesthetics and legacy intact is a key challenge.
Hence, to demonstrate the benefits of energy efficiency to the city of Kolkata, it is important that CESC House remains an energy efficient building.

CESC House Green Building Introduction
An 80 year old Heritage Building, CESC House has seen its electricity consumption growing at a rate of 2% p.a. from 29 lacs kwh in 2006 to 33 lacs kwh in 2012. Hence, the task to convert CESC House into green building was initiated.

A Going Green committee formed by CESC who initiated the task of converting CESC House into a green building by engaging Johnson Controls (India) in 2011. Later, Godrej & Boyce was roped in as green consultant for the project. After implementing the Facility Improvement Measures (FIMs) in various phases in FY`13, an application was filed with USGBC for certification in 2014

With this, several energy efficiency measures have been taken. Entire HVAC system of the building has been updated with more efficient system as per global ASHRAE standards. 1200 energy efficient lights and 52 occupancy sensors have been installed. A state of art Building Automation System, Chiller Plant Manager, Water Management System and Low flow water taps have been put into place.

All these measures attempt to take the building towards the world class green practices. Positive results of these practices are immense. Along with saving of energy and water, 966 tonne of CO2 from going into the atmosphere is also saved every year. This energy saving is despite the 2% p.a. growth in consumption witnessed in last 6 years.

The journey of an 80 year old Heritage building to the Green Corporate Office has been long and challenging!

The key challenges were:

  • Retrofit of a heritage building keeping its aesthetics and legacy intact while introducing the changes for green building. Major renovations of the façade were not possible and changes for an eco-friendly orientation had to be done wholly through non-structural renovations.
  • Arranging the 80 year old drawings and data to understand the existing site was time consuming
  • Doing the cost benefit analysis and getting the capital investment for the project
  • Considerable planning was involved in getting the green measures implemented in an existing and operational facility. The retrofits had to be done without downtime on existing premises and its operations. All the measures were done after office hours, nights or on holidays. The biggest achievement for the project was that there was not even a single complaint from occupants about discomfort while in office. Green building team considered the comfort of teams working on Sundays/late evenings
  • Upgrading an existing building as per Green Standards takes longer time frames compared to new construction.
  • Coordination with the cross functional team of CESC on continuous basis to execute the milestones within timeline wasn’t easy.
  • Stepping up the resource constraints, space was limited to accommodate today’s sophisticated technological systems needed to obtain the energy savings criteria under the LEED rating system
  • To get the support of employees, a huge time has been spent on making them understand its importance and inculcate the practices.

This initiative has been recognized nationally in June 2014. CESC House has bagged first runner-up position in the CII-NDTV- Mission Energy Challenge under commercial building category. All the winners were awarded by the esteemed jury and the event was telecast in NDTV. This award recognized the commitment of RP-Sanjiv Goenka Group and CESC towards energy conservation.

Copy of the Certificate >>

Facility Improvement Measures taken and benefits achieved
The enormous task has been taken to improve more than 30 years old and highly inefficient equipment of the building

  1. Energy Efficient HVAC System

    • Installation of a 2X 170 TR high efficiency chillers
    • Dismantle the existing 1X185 TR and 2X86TR chillers being used under de rated condition
    • Efficiency of the chillers have improved by 50%
      Cooling Tower

    • Installation of 1X500 TR Energy Efficient Cooling Tower.
    • Dismantle the existing 1X300 TR Cooling tower being used under de rated condition
      Electrical Panel

    • The HVAC system is now connected to upgraded LTAC panel.HVAC Water Pumps


  2. HVAC Water Pumps
    • Primary Pumps
      • Replaced 3 existing primary pumps with 3 energy efficient pumps & motors designed to meet the flow and head requirement
      • The new pumps will increase the pumps efficiency by 40%

Steps carried out to reduce energy consumption Quantitative benefits
 1 500 CFL lamps in common areas of entire CESC House was replaced with highly energy efficient LED lighting Annual electricity savings: 79,935 units
Carbon Footprint Reduction: 120 Tonnes of CO2
Equivalent No. of Trees planted: 4,490
2 To optimally use the HVAC system, it has been rescheduled to start 1/2 hour late and stop 1/2 hour early from its usual time Annual electricity savings of one hour. Practice of efficient operational method
3 60 nos of occupany and lux sensors have been installed which switches off a cabin light within 20 minutes, of the occupant leaving his/her cabin Non measurable energy saving as it is dependent on usage. During day light condition sensor saves electricity by deactivating the light.
4 Solar Reflective paint in roof SRI Paints are excellent roofing material that reflects the sunlight and prevents the roof from getting heated. It can achieve attractive power saving of upto 40% during peak summers in air-conditioned and humidification areas like Kolkata.
5 Use of glass windows to utilize natural day light CESC House had all the wooden windows. Now a sound and heat proof glass windows has been installed to utilize natural day light. Also, trees were in those windows to create green ambience in the building
6 Exhaust fans in toilets and pantry will be replaced with energy efficient ones The exhaust fans used in the building were inefficient is now replaced with energy saving fans
7 Low flow water faucets in all toilets. Water Saving
Indirect Energy Saving via reducing less water to be pumped
8 Change the HVAC set points to two degrees higher than current level Direct Energy Saving
9 Installation of Water Management System for Cooling tower Annual electricity savings: 58,776 units
Carbon Footprint Reduction: 88 Tonnes of CO2
Equivalent No. of Trees planted: 3292
10 Solar energy use for water heating in pantry Annual electricity savings: 1500 units
Carbon Footprint Reduction: 2 Tonnes of CO2
Equivalent No. of Trees planted: 84
11 Chiller Plant Manager: Reduction in lead time for rectifying errors in HVAC system leading to saving energy Annual electricity savings: 51,903 units
Carbon Footprint Reduction: 78 Tonnes of CO2
Equivalent No. of Trees planted: 2907
12 Purchase of Star Rated Split ACs Energy saving
A culture of Green Purchasing will be developed all across the organization
13 Internal communication for environment protection Create awareness among employees and their family, consumers, peers and next generation
14 Energy saving policy Policy to create awareness so that all future decisions are inclined to save energy
  1. Direct Energy Savings

The facility improvement measures under Green Building started from FY12. Since then the energy consumption of CESC has fallen at levels last seen in 2005

In addition to this the initiative is saving 2 Lacs+ litres p.a. and improved the air quality in CESC House. It is heartening to note that in Feb 2015, Kolkata Municipal Corporation has notified that certified green buildings would get an additional 10% FAR. With a built up area of over 83,000 sqft, CESC House would be eligible for an additional FAR of 8,000+ sqft appx

The implementation of improvement measures to convert CESC House a Green Building has been possible due to outstanding contribution of 5 cross functional divisions of CESC headed by Mr Pradip Basu, Mr BL Chandak and Mr Rajarshi Banerjee

Division Member
Project Coordinator Mrs Priyanka Bhagat
Technical Susobhan Bhattacharya and his team
Materials Partha Bhattacharya and his team
Administration Abhijit Sarkar and his team
Estate Kushal Kundu, Pranab Raha Roy and his team