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New Power Plant Will Break Even in 6 Years

By Daniel C. Stevenson
Associate News Editor

Construction of the new $37 million cogeneration power plant is continuing on schedule, according to Superintendent of Utilities Roger Moore. Construction of a second power bus will be completed in June, providing a backup that will help reduce the number of severe power outages, Moore said.

The plant, expected to be operational in early 1995, is "going to save the Institute money, going to save the area pollution, and going to give the Institute a much more secure electric system," Moore said.

"We're expecting a 14 percent cut in utility costs over the 25-year life of the project," Moore said. The cost of the project is around $40 million and "the simple payback [the break-even point] is between six and seven years."

In cogeneration, the combustion exhaust gases created by electric-producing turbines are then used to heat steam for other energy resources. "The gas turbine exhaust is like a jet engine," Moore said. "It exhausts into a heat recovery steam generator."

Foundations being laid

The completed plant will contain a 21-megawatt combustion turbine generator and a supplementary heat recovery steam generator, according to Moore. The steam produced by the steam generator will be released into the existing campus heating and cooling system. The plant will be built at the Central Utility Plant buildings on Vassar Street.

The new plant will retain three of its five boilers to aid the new turbine during peak system load duty, Moore said. Of the remaining two boilers, one will be demolished and the other retired, he said.

"Currently, we've got all the foundations in for the new boiler and the new turbine," Moore said. Additionally, workers have installed a new Westinghouse state-of-the-art distributed control system is in place, and they are installing new instruments in one of the five boilers used in the old system, he said.

Physical Plant is also installing "a completely new bulk electrical distribution system" and a new control room, Moore said.

Severe outages occurred in February and March because Physical Plant had to completely demolish Substation Number One to make room for the cogeneration plant, Moore said. The demolition of the substation eliminated some of the backups and made the power system more susceptible to component failure, he said.

"Two of the outages were a result of some of the components of our new electric switching gear," Moore said. The equipment had apparently been "wired improperly at the factory."

The latest and most severe outage on March 23 was caused by a connection that faulted in the new switch gear, Moore said.

In a letter about the outage, Physical Plant Director Victoria V. Sirianni said a bolted connection between breakers overheated and subsequently flashed.

"We are caught in the proverbial Catch-22," Sirianni said. "Until we complete the installation of the B bus in June, we will not be able to achieve the redundancy and protection we need; but to finish the job, we must eliminate and modify the protection we have right now on a daily basis."

New technology used

Originally, Physical Plant had wanted to use a General Electric LM-2500 turbine in the plant. But the Massachusetts Department of Environmental Protection refused to issue a permit allowing MIT to use the LM-2500's water injection pollution control system, because it allowed too many pollutants to escape.

Physical Plant eventually decided to use an ASEA Brown Boveri GT10 gas turbine, which had much lower levels of nitrous oxides, Moore said. A permit was granted for the new turbine in April, 1992, and the Corporation gave full approval on Oct. 2, 1992.

The new system was suggested by Professor of Chemical Engineering Emerits J2/3anos M. Be2/3er, former director of the Experimental Combustion Lab. The system was being developed in Sweden and Switzerland at the time.