Power from waste project not powered up

Chennai:The bio-methanation plant near the Koyambedu Wholesale Market Complex.The pilot project to produce electricity from the Koyambedu market’s green waste is not functioning at optimal levels, Chennai Metropolitan Development Authority (CMDA) officials have said. The agency that clears garbage from the three wholesale complexes has complained that traders do not use the appropriate spots for dumping garbage, often leaving the waste on the floor.Leafy waste such as banana leaves, packaging material which forms a bulk of the disposed material, and muddy green waste cannot be used for power generation, officials said. A vegetable retail chain is also sending some of its waste to the plant currently, but that forms only a small percentage.

The seasonal change in availability of vegetables and fruits also drastically reduces the amount of waste that is usable. The plant, that was to be run 20 hours a day at full capacity, sometimes runs for five to six hours.The CMDA was already saving substantially on the transport of waste to the Kodungaiyur dumping ground, possibly as much as Rs. 13 lakh a year, the officials estimate. However, the Tamil Nadu Electricity Bill (TNEB) bill for the Koyambedu Market Complex was expected to be almost entirely offset by power generated. Officials said that the amount debited for each unit of electricity given to the TNEB as against each unit consumed was lower by Rs. 2 or 3.

The TNEB has said that adjustment for making the costs ‘equal’ is not its policy. The Rs. 5 crore bio-methanation plant was commissioned late in 2005 following an estimation that 30 tonnes of green waste daily would be sufficient to produce 250 kilowatts (KW) of power per hour (One KW per hour is one unit of electricity). Some 40 per cent of this power would be used to keep the plant running and the remainder be exported to the TNEB. These numbers required some intelligent guesswork, as this was the first time such a project was being attempted, officials pointed out. Three quarters of the project cost was funded by the Ministry of Non-Conventional Energy Sources.

Since the Wholesale Market Complex generates up to 100 tonnes of garbage a day, it was expected that 30 tonnes of garbage suitable for power generation could be easily segregated. One percentage each of flower, fruit and vegetable waste is required to provide non-fibrous green waste that could be disintegrated into smaller pieces. This would be ‘digested’ in a plant that would produce methane from the waste and the gas operates an engine to produce power.With the time for handover by the contractor who undertook design and construction drawing near, the CMDA will now have to consider such measures as supplementing the waste fed to the plant with hotel waste. A meeting has been scheduled for Tuesday to discuss the course of action. More than 1,000 students would have visited the plant in the nearly two years when it has been in operation and the Pune Municipality is considering replication of the project.