Environmental benefits

Does cogeneration help MIT conserve energy?

Yes. Cogeneration has been helping MIT conserve energy since 1995, and the upgraded plant will continue the conservation legacy established by the existing plant.

  • MIT’s existing cogeneration plant has used close to a third less fuel than conventional energy sources would have consumed to generate the same amount of electricity and steam. 
  • 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. 
  • The upgraded plant’s new state-of-the-art equipment and technology will increase overall plant efficiency. 

Has cogeneration at MIT also helped reduce pollutants?

Yes. The existing cogen plant has protected the environment in a variety of ways.

  • Since the 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 compared to conventional energy sources, according to the EPA. 
  • If MIT had relied instead on conventional energy sources (purchasing all of its electricity from the grid, and using natural gas boilers to generate steam), the energy production process would have added almost 1.3 million metric tons of GHG emissions to the planet’s atmosphere. 
  • 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. 

How will the upgraded plant help MIT further reduce its greenhouse gas and pollutant emissions?

Thanks to new and/or upgraded equipment at the CUP, MIT will be able to reduce its plant emissions substantially. 

  • 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. This fuel is the same natural gas that is used to heat homes.
  • Modeling shows that in 2020, even though energy demands on campus will have increased due to new buildings and other research requirements, the upgraded plant’s greenhouse gas emissions will be 10% lower than 2014 plant emissions. The plant upgrades are essential to MIT’s commitment to reducing campus GHG emissions at least 32% by 2030, detailed in our Plan for Action on Climate Change.
  • The two new gas turbines will be more efficient and environmentally friendly than the plant’s existing turbine. The new turbines will have a lower exhaust temperature, and they will use state-of-the-art controls to reduce pollutants. These controls include catalysts that will reduce the plant’s NOx (nitrogen oxides) emissions by 90% compared to the current system.
  • A condensing economizer (hot water) coil will be installed to capture additional waste heat from the exhaust stream after the heat recovery steam generation process. MIT plans to distribute the resulting heated water around campus through an expanded medium temperature hot water loop, to provide heat and hot water to MIT buildings. When that system is established and the coil is capturing heat, the temperature in the plant stack will be lowered. This will raise the efficiency of the plant’s overall operation and enable MIT to further reduce its greenhouse gas emissions.
  • The upgraded plant will enable MIT to eliminate the use of fuel oil in campus power generation by 2020. Our new gas service agreement with Eversource will enable the cogeneration plant to run entirely on natural gas with the exception of emergencies and testing. This will assist MIT with its efforts to reduce emissions. 
  • In addition, MIT will eliminate all use of #6 oil on campus by 2019, modifying the plant’s three older boilers to make them compatible with cleaner #2 fuel oil. In the case of an emergency (when the natural gas supply is interrupted) or in a testing situation, the boilers will burn #2 oil only. (The plant’s two newer boilers already burn this cleaner fuel.) Cleaner fuel means fewer particulates in the air.

How does MIT measure greenhouse gas emissions on campus?

To measure campus greenhouse gas emissions, MIT uses the Operational Control Approach as defined by the World Resources Institute’s GHG Protocol. The Office of Sustainability provides detailed information about MIT's greenhouse gas emissions measuring and inventories

What else is better about the new and/or upgraded plant equipment?

In addition to installing more efficient gas turbines, cooling towers, and other equipment for the cogeneration system, MIT will also modify the plant’s three older boilers to make them compatible with cleaner #2 fuel oil. This will eliminate the use of #6 oil on campus by 2019 – and cleaner fuel means lower emissions. (Note that the boilers will primarily burn natural gas. #2 fuel will be used only for testing or if there is a disruption in the natural gas supply.)

I heard that MIT has voluntarily requested a 30% reduction of the CUP emissions cap in the permit for the upgrade project. Is this true?

Yes. Although the upgraded plant will generate more energy than the existing plant, it is capable of generating it with lower overall emissions. Furthermore, in a departure from the typical permitting process, MIT and MassDEP are pursuing (at MIT’s request) a strategy to reduce overall plant emissions by permitting the plant’s most efficient and lowest-emitting equipment (its newer boilers, for example) to operate first. MIT’s permit application details MIT’s interest in achieving significant emissions reductions under the new permit compared to the existing permit. 

Why did MIT request this unconventional permitting structure?

In addition to the new natural gas contract negotiated with Eversource, MIT’s decision to voluntarily upgrade its older boilers and partner with MassDEP in creating this permitting structure is a reflection of the Institute’s evolving energy strategy. To support our commitment to a more sustainable campus, MIT is moving forward with an energy model that integrates climate change mitigation with economic considerations.