While Tunnel Boring Machines (TBMs) mean faster work for Pune Metro, they also mean big revenue for Maharashtra State Electricity Distribution Corporation Ltd. As per officials, TBMs, two of which are presently employed by Metro in Shivajinagar, need 11,000 KV each daily.
In the first month of operations, when just one machine was fully operational, it consumed about 2.8 lakh units of power generating a bill of Rs 45 lakh for the power utility.
As the second TBM has also become fully operational from January and two more are expected to join tunnelling work from Swargate-end, the power bill can easily cross about Rs 1.5 crore per month.
The work is expected to take about two years and thus in Pune Metro, MSEDCL has found a big client, although temporary. But Pune Metro officials said the deal is much cheaper if compared with operations where TBMs are operated on power generated by diesel generators owing to lack of power supply facilities. “If the work is to be done in a short time and there is no need to set up grid supply as was the case in Lucknow and recent works in Delhi, there is no option but to generate power using diesel for TBM operations. In such cases, it turns out to be very expensive. It may cost about 30 per cent more,” an official said.
The TBMs in Pune, called Mula and Mutha after the two rivers that criss-cross the city, dig their way through and clear 8-10 metres everyday. Each TBM is 6.65 metre wide and 120 metre long. It has a cutter-head in front, which has ‘teeth’ which rotates at six revolutions per minute (RPM).