MUMBAI: In an operations control room in Tata Consultancy Services Kochi campus, 12 employees keep an eye on the IT firm’s 100 buildings across the country. The employees aren’t security.The control room monitors real-time electricity usage and uses sensors, big data and analytics to tweak chiller and lighting systems of the firm to cut wastage on a daily basis."You can have systems that tell you how much energy you have used. But there is no point knowing that you should have switched off your AC yesterday," Rajesh Gopinathan , CFO of TCS , told ET. "This system makes accurate predictions that can be acted upon in real-time."TCS — which employs about 2,50,000 people and expects to add 60,000 more this year — spends roughly Rs 500 crore on electricity per annum.To crimp this bill, TCS decided focus on wastage of electricity. Gopinathan, also the chief driver of the project, set up a team that included executives from the corporate technology office, engineering R&D and digital business to create a company-wide system to monitor and control electricity wastage.To begin with, TCS designed a sensor that would not just keep tabs on electricity consumption of its massive chiller units (that keep campuses cool) but also was capable of executing commands like powering down these units.Then, the company wrote a software code that would pull data from sensors that were placed at its 100 odd campuses. An analytics interface was created to unify and crunch data from air-conditioners, lights, computing systems.The results are showing. In the 11 months since the system was put in place, TCS managed to keep its electricity spend flat — despite its seating capacity going up 15%."It is easy to do things on a new campus but some of our buildings are 40 yearsold and the equipment is old. This is the true part of sustainability -- to cut waste," Gopinathan said.Indian IT firms have been increasingly focussed on burnishing their sustainability credentials. Infosys has built a solar power plant at its centre in Hyderabad and is running it completely off the electricity grid.However, other than TCS, no company has implemented such an integrated, centrally-controlled system to save electricity across all its Indian centres.The Mumbai-headquartered company now wants to take this project a step further. It has also built a trading system to allow it to buy just as much power as it needs at favourable costs, when the electricity market in India reaches that level."This system tells us accurately how much energy we need in a week. I can contract with power producers at times, when I get the lowest prices.The market isn’t there yet, but when it reaches that level, we will be ready," Gopinathan said, adding that Tata Consultancy Services would use the system to win clients in the energy management space."We currently have clients, but that is more remote monitoring. It is passive. With this system, we can now do active monitoring. The space is fragmented but given the way technology is changing, I would say the potential is unbounded," he said.He pegged the energy management services market at about $40 billion a year. Earlier this week, Wipro announced it had won an energy management contract from Jubilant Foods.