Stanford University on April 16 announced a series of new initiatives to clean up its electricity sources, including the shutdown and planned dismantling of a gas-fired cogeneration plant and the addition of new on- and off-campus solar energy sources.
The comprehensive new system incorporates solar power for electricity, combined with heat recovery, to allow the university to exceed the aggressive greenhouse gas emissions reduction goals of California’s landmark AB 32 Global Warming Solutions Act. It eliminates 150,000 tons of CO2 emissions annually. Stanford University has converted to a state-of-the-art energy system that relies on renewable electricity and provides a new transformational energy supply model for large organizations, utilities and governments.
The university announced a new agreement to provide the majority of its campus electricity from renewable sources within California. A Stanford Solar Generating Station, to be designed and built by SunPower, is expected to provide half of all campus electricity. Combined with planned solar power from installations on campus rooftops and the purchase of further renewable power from the grid, renewable energy will supply 65% of all campus electricity. The renewable energy is joined by a first-of-its-kind campus heat recovery system, which began operating March 24 to heat and cool campus buildings.
The combined new system – called the Stanford Energy System Innovations (SESI) – makes Stanford one of the most energy-efficient research universities in the world. It far exceeds the aggressive goals of AB 32, which seeks to reduce greenhouse gas emissions to 1990 levels by 2020.
In addition to the deep reduction in reliance on fossil fuels, SESI cuts the university’s greenhouse gas emissions by 68%. It will save Stanford $420 million over 35 years (as compared to a cogeneration option) and will reduce total campus water use by about 15%.
“SESI achieves a stunning and unprecedented reduction in Stanford’s carbon footprint and water usage,” said Stanford President John Hennessy. “We believe this system can be a model for others equally concerned about reducing greenhouse gas emissions and willing to make an investment in the future. SESI is a transformational energy system for the 21st century, and we look forward to sharing the technology with others.”
SunPower to build off-campus and on-campus solar capacity
Stanford has entered into an agreement with SunPower to build a 68-MW (peak) solar plant on approximately 300 acres in California. The solar farm, which will be called the Stanford Solar Generating Station, will be comprised of more than 150,000 high efficiency SunPower solar panels. Stanford Solar is expected to come online in late 2016. SunPower hasalso been selected by Stanford to install about 5 MW of rooftop solar systems on campus. Together with the Stanford Solar plant, the solar systems will provide about 53% of Stanford’s total electricity use.
“Stanford’s bold initiative to integrate cost-effective, sustainable energy solutions to power its operations is unparalleled, and we applaud the university’s commitment,” said Tom Werner, SunPower CEO and president.
The remaining 47% of Stanford’s electricity will come from California grid power, resulting in another 12% of which is renewable. Because about one-fourth of California grid power is renewable (and that will increase to 33% by 2020 under state regulations), Stanford’s total power mix will provide at least 65% clean electricity to campus buildings.
Also key to SESI is the new, on-campus Central Energy Facility (CEF) that relies on a heat-recovery process that is 70% more efficient than the cogeneration process Stanford had used since 1987. The CEF will meet more than 90% of campus heating demands by capturing almost two-thirds of the waste heat generated by the campus cooling system to produce hot water for the heating system. The CEF, which also includes a high-voltage substation, is run by a patented “model-predictive-control” software system developed at Stanford that optimizes cost and energy efficiency.
Key partners in building the SESI plant include Whiting-Turner, Affiliated Engineers Inc., ZGF Architects, Johnson Controls Inc. and Siemens.
SESI began supplying campus energy on March 24, simultaneously with the decommissioning of the 30-year-old, natural-gas cogeneration plant, which supplied virtually all of the university’s needs. The obsolete cogen plant, which will be demolished after all useful parts are sold for reuse, was considered remarkably efficient for its time.
“By significantly reducing natural gas usage and electrifying the campus heating and cooling system, we enabled the university’s energy supply to be substantially transitioned from fossil fuels with volatile and unpredictable long-term prices to clean renewable electricity sources with affordable costs fixed for a very long time,” said Joseph Stagner, executive director of Sustainability and Energy Management at Stanford.