Stanford University
OP-6: Clean and Renewable Energy

In addition to the seventeen sites that already had rooftop solar, panels were also added to 15 additional sites on Stanford’s campus in March 2017 with a production capacity of approximately 4.5 MW. The figure above includes 10 months of data for just the original sites, and 2 months of data that includes the new sites as well. More information on the launch of the on-site solar can be found in the following Stanford Report article: http://news.stanford.edu/2017/04/17/sun-rooftop-photovoltaic-panels-electricity-stanford/

As of early 2017, 65% of Stanford’s electricity comes from renewable sources. These sources include the 67 MW Stanford Solar Generating Station located in southern California and the 4.5 MW of on-site rooftop solar mentioned above, as well as additional renewable electricity from the California grid. This transition to renewable sources, along with the efficiencies gained from the transition from cogeneration to a heat-recovery based distributed heating and cooling system, will reduce Stanford’s greenhouse gas emissions by approximately 68% between 2011 and 2017.

Waste heat recovered from chilled water is used to produce hot water for building heating.

Stanford has a power purchase agreement with SunPower to purchase all electricity and bundled RECs from the 67 MW Stanford Solar Generating Station located in southern California. The plant uses SunPower’s state-of-the-art PV technology with single axis tracking. The plant came online in December 2016 and Stanford has agreed to purchase the generated electricity and RECs for the next 25 years. All RECs generated by the plant meet California’s Renewable Portfolio Standard’s Level 1 Portfolio Content Category definition, ensuring they are bundled, in-state, and additional. Stanford’s REC purchases are tracked through the Western Renewable Energy Generation Information System (WREGIS). More information on the launch of the Stanford Solar Generating Station can be found in the following Stanford Report article: http://news.stanford.edu/2016/12/05/stanford-unveils-innovative-solar-generating-station/

The source breakdown above is derived from the 2014 power content labels for California utilities (2015 power content labels have not yet been released). The power content percentage for each utility by source has been applied to the energy purchased by Stanford from that utility for calendar year 2016 to derive the percentages above. The solar generated onsite was then included in the solar category. The “Other” sources of electricity are listed as “Other/unspecified” on the utility power content labels and represent market purchases for which the source is not tracked by the utilities. It is worth noting that the City of Palo Alto Utilities, which provided about 11% of Stanford’s electricity in 2016, purchases RECs for all of their electricity from unspecified sources, so all of it can be considered renewable.

The vast majority of campus building heating needs are met by hot water generated from Stanford's new Central Energy Facility, which uses heat recovery chillers to recover the waste heat from the chilled water that Stanford uses to cool its buildings to create hot water used for heating. Through this process, Stanford is able to meet 93% of its campus heating needs with waste heat from its chilled water system. The natural gas used for building heating goes towards backup hot water generators when the demand for building heating is so high that the need cannot be met with the hot water produced through heat recovery. Finally, natural gas also goes to some buildings directly on campus for building heating that do not receive energy from Stanford's Central Energy Facility.

Due to the significant heat recovery and lower line losses of hot water compared to steam, the new energy system is approximately 70% more efficient that the previous combined heat and power process provided by cogeneration, which was employed at Stanford since 1987 until the launch of the new energy system in April 2015. For more details, please visit: http://sustainable.stanford.edu/sesi.