DATA SOURCES

Data SourcesHarvard's Engineering and Utilities Department keeps detailed records of electric, steam, chilled water, and fuel consumption on the Cambridge/Allston campus. Their database was the source for much of our input data. Longwood area data comes from energy managers who track utility usage. Data about the MATEP cogeneration plant comes from employees of the plant. For both the Cambridge/Allston campus and the Longwood Area, the Inventory's scope includes:

  1. Electric Use
    Harvard purchases electricity for the Cambridge/Allston campus from the regional grid, and the Longwood campus buys energy from the MATEP cogeneration plant. All purchased electricity for which records were found has been included for the 23 buildings in the Longwood Inventory and 343 in the Cambridge / Allston Inventory.
  2. Steam Use
    Harvard's Blackstone Steam Plant produces steam to heat most of the Cambridge and Allston campus. Detailed fuel use records are available for the Blackstone Plant, and we have developed conversion factors that are specific to our steam plant that vary by year as fuel use and mix varies. Longwood's steam comes from the MATEP cogeneration plant, for which we have also developed specific, year-by-year conversion factors. All available steam use data has been included in the Inventory.
  3. Chilled Water
    Harvard produces water at a centralized chiller plant in the Harvard Science Center. This plant utilize electric chillers, and its electric consumption and production efficiency is carefully tracked. We have developed conversion factors that are specific to our chilled water plants that vary year by year. There are also several smaller chiller plants, most notably at the Harvard Business school. The electricity consumed by these units is captured in general "electric use." Longwood's chilled water comes from the MATEP cogeneration plant, for which we have also developed specific, year-by-year conversion factors. All available chilled water data has been included in the Inventory.
  4. On-Campus Stationary Sources
    Not all buildings at Harvard are connected to the central utility system; therefore, there are many boilers, hot water heaters, emergency generators, and furnaces on campus that use natural gas, fuel oil #2 (diesel), or fuel oil #4. This fuel use is largely tracked by UOS's utility database, and all available stationary fuel use data has been incorporated into the Inventory.

Units of Measurement

Harvard's emissions are reported in MTCDE --Metric Tons (1000 kg) of Carbon Dioxide Equivalent. MTCDE include greenhouse gasses other than CO2, such as:

  • Methane (CH4)
  • Nitrous oxide (N2O)

These gasses are actually more powerful that CO2 as contributors to the greenhouse effect. These species' "global warming potentials" have been calculated and are 23 and 296, respectively. This means that one ton of methane will cause 23 times as much warming (or radiative forcing) as one ton of CO2.

All greenhouse gas inventories should report emissions in MTCDE!