Caltech's Path to Decarbonization

Caltech’s innovative, industrious research apparatus hides a dirty secret: a reliance on fossil fuels. But that is set to change. Last fall, President Rosenbaum endorsed a proposal from the Caltech Sustainability Advisory Council to source carbon-free energy for Campus. This proposal allows Caltech’s facilities to electrify campus operations and begin negotiations with Pasadena Water and Power (PWP) to source green energy. 

Currently electricity and heating for campus is largely generated by the on-campus power plant, located next to the North Athletic Field. Opened in 2003, this cogeneration facility is the 3rd iteration of the on-campus power plant that was originally built in 1968 to provide energy independence to Caltech. The plant boasts a turbine engine capable of providing 12.5MW of electricity and heating which is distributed to the university through power lines and steam pipes.

While Caltech occasionally buys power from PWP to meet its peak demand (often in the height of the summer to power air-conditioning), the cogen facility sells energy back to PWP under reduced load so that Caltech is energy neutral most years. Additional electricity is provided by several Bloom fuel cells on campus. Although Caltech’s energy production is cleaner than many universities, its portfolio’s reliance on natural gas limits its decarbonization efforts.

Due to pressure from the student body, Caltech formed a Sustainability Advisory Council in 2023 to oversee sustainability efforts and identify areas of improvement. The board of 12 includes Caltech’s Provost, Vice President, and Chief Sustainability Officer, among other stakeholders, students, and professors. Among the student’s petitioned requests were carbon neutrality by 2050, off site clean energy, integrated environmental education, and the reintroduction and expansion of reusable dining goods. 

In line with these efforts, the sustainability council advised Caltech to buy carbon-free energy in collaboration with PWP. Caltech and PWP’s longstanding, collaborative relationship is due to their interreliance: Caltech is Pasadena’s single largest energy consumer and PWP’s grid is literally married at Caltech with the only substation connecting east and west Pasadena right behind Red Door Cafe. 

Caltech and PWP will eventually negotiate a power purchase agreement (PPA) for non-carbon energy. PWP currently sources energy from a variety of installations from around California and neighboring states. Among the renewables include solar farms in the Mojave desert, wind turbines in the Bay Area and Milford Utah, hydroelectric from Azusa and the Hoover dam, landfill gas from various LA basin landfills, and geothermal from the Salton Sea basin. All combined, renewables accounted for 40% of Pasadena’s energy use in 2022. 

Contrary to Caltech’s green initiatives, a coal installation in Utah accounts for almost a quarter of Pasadena’s power usage. Natural gas has become the preferred option for remaining demand with turbines similar to Caltech’s supplying power through the Glenarm Power Plant next to the beginning of hwy 110. Yet, there is hope for Pasadena as its coal contract expires in 2025 and it has committed to 100% carbon-free energy by 2030. California has imposed additional restrictions on public utilities which requires them to decarbonize by 2045.  

Similar decarbonization efforts are underway at many other universities including a few that are already carbon neutral including Stanford, American University, and several colleges in the northeast. Approaches vary among universities with some opting for carbon offsets (with dubious efficacy), others installing more efficient power plants to replace dated infrastructure and dirty fuels, and yet others signing PPAs that provide resources to build off campus energy production or buy renewable energy from a specific renewable energy installment. The completion of two photovoltaic installations in central California through PPAs brought Stanford to 100% renewable in 2022

Yet, Caltech’s uniqueness falls in its desire not just to decarbonize but to match our current energy needs. In an interview with Campus Sustainability Officer John Onderdonk, he mentioned “our approach to sustainability is true to Caltech’s culture – we want to understand the dynamics of the challenge and engineer around it.” Caltech can buy carbon offsets or clean energy from PWP immediately, but these have questionable efficacy and would not sustainably integrate into Caltech’s infrastructure. 

The engineering problem can be split into two parts: Caltech’s unique energy demand and its steam powered infrastructure. First, Caltech’s constant energy demand is different from the rest of the grid whose energy needs are low at night and high during the day. Research labs are remarkably consistent energy consumers as many research instruments such as fume hoods, freezers, servers, and vivariums require 24/7 electricity. Both the demands of Caltech and Pasadena are at odds with solar and wind supplies which often produce during narrow hours of the day, thus mandating battery storage for their sustained use. 

Consistent producers of electricity such as geothermal, hydroelectric, nuclear, and wave match Caltech’s largely unyielding power demands. Caltech is only supporting additive installations to flatten the supply curve that will explicitly expand upon PWP’s carbon-free energy supply and thereby eliminating any concern that clean energy bought from PWP may shift Caltech’s emissions onto others. 

In addition, Caltech’s infrastructure is not ready for overnight electrification. The holdup is mainly due to the efficiency of the cogeneration plant. Because campus heating is a byproduct of its energy production, the electrification is not straightforward. Converting from steam to hot water is a daunting engineering task requiring massive investments in new heat exchangers, piping, and thermal storage. Caltech’s sustainability office is searching for an engineering firm up to the task yet it will likely be years until this transformation will occur.

The energy distribution problem among daily use is also studied on campus by several labs including Steven Low and Adam Wierman who contribute extensively to Caltech and Pasadena’s smart grid efforts. Among their efforts is the integration of point sensors including smart thermostats, motion detectors, and EV chargers. 

The last mile problem also applies to our energy use. Whatever tertiary carbon is generated by fertilizer for landscaping or gas guzzling cars for commuting, Caltech may buy carbon offsets to meet the broadest and most difficult to manage of the scope 3 emissions categories. 

Unlike Caltech, many universities have implemented timelines on when they expect projects to be completed. All University of California (UC) schools are expected to buy external carbon free energy by 2025 and make drastic internal reductions by 2030. UC Berkeley has a similar cogeneration plant as Caltech and a similar plan to electrify heating and cooling is expected to have its system up and running by 2028 and fully connected by 2030.

Despite Caltech’s long path to decarbonization, its infrastructure should be sustainable for many years to come while providing the next generation of researchers the tools they need to change the world.