Prior to the new Central Energy Facility developed through SESI, an intertwined system of steam and chilled water met the simultaneous demand for heating and cooling of campus buildings. Steam from the Cardinal Cogen plant entered the building, and through heat exchangers, produced both warm air for space conditioning and hot water for restrooms, kitchens, and laboratories. Afterwards, the steam changed into condensate, and returned to Cardinal Cogen to be reheated back into steam and then sent out to buildings again. Simultaneous to the steam system, chilled water entered the building, and through a different heat exchanger, provided cold air to cool the building. After collecting waste heat, the chilled water then was piped back to the facility for re-cooling.
Plan Approval and Report
In December 2011, Stanford’s Board of Trustees gave concept approval to the Stanford Energy System Innovations (SESI) project, which is a collection of operationally distinct initiatives designed to meet the university’s energy demand while reducing greenhouse gas emissions and water consumption. SESI represents a significant transformation of the university from 100% fossil-fuel-based cogeneration to a more efficient electric heat recovery system and will result in immense benefits for Stanford in the years to come. The SESI project has reduced campus greenhouse gas emissions by 68% from peak levels, and saved 18% of campus potable water, in its first year of operation. These savings will continue to increase as the project opens up the energy supply to future technologies and enables the campus to better manage its power portfolio by incorporating renewables.
2015 Energy and Climate Plan - PDF
Implementation of the SESI program involved significant work throughout the campus between 2012 and 2015. The Department of Project Management managed design and construction of 22 miles of hot-water pipe, conversion of 155 buildings to receive hot water instead of steam, and installation of the Central Energy Facility (CEF) and a new campus high-voltage substation. View a timelapse video detailing construction of the new CEF.
This work was carefully sequenced in multiple phases to minimize disruption to campus life. As each phase of piping and building conversion was completed, that section of campus moved off steam and transitioned to hot water via a regional heat exchanger that converts steam from the existing cogeneration plant to hot water at a district level. A full transition from the cogeneration plant to the new CEF took place in April 2015, the regional heat exchange stations were removed, and the cogeneration plant decommissioned and removed to make way for new academic buildings within the campus core.