Cogeneration: a sustainable choice

Cogeneration is a clean, efficient, and cost-effective choice for power production. Its benefits are the result of generating two types of energy from one fuel. In MIT’s case, electrical and thermal energy are both generated from a single natural gas turbine. The necessary replacement of the existing cogeneration turbine in the Central Utilities Plant (CUP) presents MIT with a valuable opportunity to renew and strengthen its commitment to energy conservation and effective climate change mitigation.

Pollutant reductions

  • The upgraded CUP will use natural gas for all normal operations, lowering the plant's regulated pollutant emissions more than 25% from 2014 emissions levels.
  • The two new turbines will be cleaner and more efficient. Their state-of-the-art emissions controls include two different catalysts that will reduce the plant's NOx (nitrogen oxides) emissions by 90% compared to the current system.
  • MIT’s new gas supply agreement with Eversource will enable the plant to run entirely on natural gas by 2020, eliminating the use of fuel oil except for emergencies and testing. This will further reduce emissions. 
  • When upgraded, the plant’s boilers will all be compatible with cleaner #2 fuel, eliminating the use of #6 oil on campus by 2019. On the rare occasions when fuel oil is required for testing or during an emergency, only #2 fuel will be used.
  • New cooling towers with high-efficiency drift eliminators will also help reduce particulate emissions and conserve water.

Greenhouse gas reductions

  • The upgraded plant supports MIT’s goal of reducing campus greenhouse gas emissions at least 32% by 2030. 
  • Modeling shows that in 2020, even though energy consumption on campus will have increased due to new buildings and other demands, the upgraded plant’s greenhouse gas emissions will be 10% lower than 2014 plant emissions. 
  • This reduction is above and beyond the CUP’s current greenhouse gas emissions benefits. Since the cogeneration plant came on line in 1995, MIT has achieved annual reductions in greenhouse gas emissions of 15%-20% compared to conventional boilers and utility power. 
  • During the 20 years since then, the Institute has avoided an average of 68,000 metric tons of carbon dioxide emissions each year, according to the EPA. 
  • In 2013 alone, the GHG emissions avoided by MIT were equal to the emissions generated by the electricity use in more than 8,000 single-family homes over a period of one year. 
  • The existing plant received the Energy Star Combined Heat and Power Award  in 2002 for environmental excellence from the U.S. Environmental Protection Agency (EPA) and the Department of Energy. 

In MIT’s cogeneration plant, a natural gas turbine powers a generator to produce electricity for campus buildings. Waste heat from the turbine exhaust is converted into thermal energy by a heat recovery steam generator, and the resulting steam and hot water are used for on-campus heating and cooling. The plant upgrade will increase its power capacity while reducing emissions.