October 9, 2012
Stanford's first-of-its kind energy facility will help it cut carbon emissions in half
The Stanford Energy System Innovations, four years in the making, will be among the most energy efficient systems of any major research university in the world. Among its innovations is a Stanford-invented technology that will be used to operate a new energy facility, while simultaneously seeking the most cost-effective electricity available on the market.
By Kate Chesley
Artist's rendering of Stanford's new energy facility. (Rendering: ZGF Architects)
Stanford University will break ground on Wednesday, Oct. 10, on a first-of-its-kind energy facility that will be key to reducing the campus' carbon emissions by 50 percent, cutting water use by 18 percent and saving an estimated $300 million over the next 35 years.
The new facility is part of the Stanford Energy System Innovations (SESI), a project scheduled for completion in 2015. When fully implemented, SESI will be among the most energy-efficient systems of any major research university in the world, according to Joseph Stagner, the executive director of sustainability and energy management at Stanford.
"This is a transformational change to how Stanford produces and uses energy. It's an energy system for the 21st century," Stagner said.
"It advances Stanford from 30 years of a 100-percent natural-gas based, combined heat and power system to a more efficient electricity-based, combined heat and cooling process that uses heat recovery," he said.
Four years in the planning
The comprehensive new system was four years in the planning. It evolved from a 2008 Energy and Climate Plan that involved the entire university community, including Stanford faculty members whose research focuses on the environment and sustainable energy.
As part of that Energy and Climate Plan, Stagner led a review of technologies Stanford might use to reduce its carbon emissions, meet long-term energy needs in a more sustainable way and be more efficient and economical. That review revealed that more than 80 percent of the university's heating demands could be met with waste heat already being removed from buildings by the campus cooling system.
The resulting $438 million SESI project was approved by Stanford University's Board of Trustees in December 2011. Stanford received approval to begin construction on the key new central energy facility in September from Santa Clara County.
The comprehensive new system relies on several factors. Stanford will:
- buy electricity from the energy market
- use the new central energy facility to recover and use waste heat from the campus chilled water system to meet the bulk of campus heating needs
- convert the existing central steam system for heating buildings to a more efficient hot-water system
- build a new electrical substation
- decommission its cogeneration plant
Cogeneration versus hot water and heat recovery
Since 1987, Stanford has used efficient, natural-gas-fired cogeneration for virtually all of its energy needs. The Cardinal Cogeneration plant, which produces steam, chilled water and more electricity than Stanford actually uses, is owned by General Electric.
A system like Cardinal Cogeneration works by using fossil fuel – in this case natural gas – to produce electricity and then recovering and reusing waste heat from the combustion process. Lost, however, is much of the heat generated by cooling processes, like air conditioning. That heat ends up discarded into the atmosphere through evaporative cooling towers.
In contrast, the new all-electric facility is more flexible, allowing Stanford to procure electricity from any number of diverse sources, including renewable sources like wind or solar power. The facility will be operated by an automated control system invented at Stanford. The university has sought a patent on the technology, which allows autonomous operation of the plant, while simultaneously securing the most cost-efficient electricity available at any one time.
The 125,000-gross-square-foot facility, located on the periphery of campus off Searsville Road, allows the university to regenerate the waste heat that the cogeneration plant discarded. An estimated 70 percent of the waste heat created by chilling water will now be used to supply 80 percent of the heating and hot water required for campus buildings. The new facility will feature both hot- and cold-water storage.
This type of system is possible where buildings are being cooled and heated at the same time. That's often the case at Stanford because of the region's climate and because research facilities make continuous use of refrigeration.
This simultaneous heating and cooling provides the opportunity for the transfer of excess heat, but capturing and distributing the heat has also required the replacement of about 20 miles of piping across campus and the conversion of about 150 building heating connections. Most buildings are now heated by steam; for the new system to work, the steam must be replaced with hot water. This has required the replacement of underground pipes. At this point, about three miles of pipes have been replaced.
The new pipes will be more efficient, cutting energy losses from 14 percent to less than 4 percent. They will also be safer and easier to operate and maintain.
Toward a sustainable future
"Really what we are doing is taking what the environment gives us to become more efficient," said Stagner. "We are working in harmony with nature rather than expending resources to overcome it."
Once SESI is fully implemented, Stanford's carbon impact will be reduced by amounts far exceeding the aggressive goals of California's landmark AB 32 Global Warming Solutions Act.
Beyond SESI, Stanford's energy efficiency innovations also include higher-than-required energy standards for new buildings, major retrofitting of existing buildings and programs to teach students, faculty and staff how to cut back on their energy use.
Many new buildings, for example, are constructed to be 30 percent more energy efficient than required by code. The signature building is the Jerry Yang and Akiko Yamazaki Environment and Energy Building, which uses interior atriums to guide hot air up and out, and windows that open at night to let the cool air in.
As another example, in March, the U.S. Green Building Council certified the new Knight Management Center of the Stanford Graduate School of Business as LEED Platinum, which is the highest rating for environmental sustainability.