Executive Summary Scope 1 and 2 greenhouse gas (GHG) emission from MIT owned buildings in Cambridge have largely remained constant over the past decade. The climate crisis demands that MIT takes a comprehensive set of measures to reduce its on-site carbon emissions to zero as soon as possible. To realize this goal, a series of integrated technology updates must be initiated: Figure 1: MIT campus section with key upgrade strategies - Comprehensive building retrofits across campus would reduce carbon emission by up to 40% and add to occupant comfort and well-being (1). - Adding PV on all suitable rooftops would decrease our emissions by an additional 5% depending on the carbon content of the grid (2). - Electrify our district heating and cooling system by continuing to change from steam and chilled water distribution loops to either hot and chilled water loops or a single ambient temperature water loop (3). The system choice has wide ranging repercussions and needs to be carefully studied. Both system types would be connected to a 300m deep borehole field to act as a seasonal heat source or sink (4). The hot/chilled water solution would be centrally conditioned via industrial-sized water-based heat pumps. An ambient loop would reduce energy use when coincident heating and cooling occurs but requires individual heat pumps in all campus buildings. An example for this approach will be the new Metropolitan Warehouse. A distributed system would require more space in connected buildings and might be more disruptive to install and maintain but is better suited for a phased approach. - In any case, the district energy system needs a clean source of electricity, for which we recommend pursuing two emerging emissions-free energy sources with strong ties to ongoing MIT research: deep geothermal boreholes (5) nuclear batteries (6). Alternatively, grid electricity can be used, assuming the grid itself is decarbonized and has the spare capacity to take on the campus loads. - While carbon capture technologies are evolving quickly and could largely remediate remaining emissions from on-site combustion, it remains unclear how and where MIT could sequester the resulting CO2 (7). - Given current electric tariffs in New England, battery energy storage is currently neither economically viable nor technically required since our diesel generator suite can provide emergency backup for resiliency. Economic boundary conditions and grid stability may change as the grid decarbonizes, in which case energy storage technology will become a key
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