Stanford's Central Energy Facility

Most visitors never notice the building that keeps Stanford warm. The Central Energy Facility at 506 Oak Road is a modern plant of tanks, pipes and machinery arranged around a courtyard. It is the heart of Stanford Energy System Innovations, usually shortened to SESI. When it came online in 2015, it replaced a natural gas power plant and changed how a whole campus heats and cools its buildings.

This page explains the old system and the new one, the heat recovery idea at its core, the solar plants that supply its power and how to tour it. Figures come from Stanford's SESI website and Stanford Report. For the rest of campus, start with our guide to visiting Stanford.

Before 2015: gas and steam

For almost three decades Stanford ran on cogeneration. From 1987 a natural gas plant on campus produced electricity and used the leftover heat to make steam. Stanford says it supplied virtually all of the university's energy needs. Steam traveled through pipes to buildings across campus for heating and hot water.

By the 2010s the plant was about 30 years old. Stanford studied what to do next and found that a different approach could cut emissions and costs at once. The university's trustees gave concept approval to SESI in December 2011.

How heat recovery works

The key insight is simple. A big campus needs heating and cooling at the same time, often in the same building. Labs, data centers and hospitals shed heat all year. The old system threw away the heat removed by cooling and burned gas to make more heat elsewhere.

SESI captures that heat instead. Stanford's 2015 feature explains the system this way:

• Electric heat recovery equipment collects almost two-thirds of the waste heat from the campus cooling system.
• That heat is used to make hot water for the campus heating loop.
• Heat recovery meets more than 90 percent of campus heating demand.
• Tanks store both hot and chilled water, so the plant can run when it is most efficient and draw on storage later.
• The process is 70 percent more efficient than the old cogeneration process, according to Stanford.

Because the plant runs on electricity rather than burning gas, its emissions depend on where the electricity comes from. That is where the solar plants come in.

Rebuilding the campus for hot water

Switching from steam to hot water meant digging up much of campus. According to the SESI site, crews installed 22 miles of hot water pipe and converted 155 buildings to receive hot water instead of steam. The work went on while classes and labs kept running.

The switch itself happened in spring 2015. Stanford's 2015 feature says SESI began supplying campus energy on March 24, the same day the cogeneration plant was decommissioned. The SESI site describes the full transition as taking place in April 2015. Stanford Report marked the system's 10th anniversary in April 2025.

What it achieved

The early results were large. In SESI's first year, campus greenhouse gas emissions fell 68 percent from peak levels. Stanford's 2015 feature put the cut at about 150,000 tons of carbon dioxide a year, comparable to taking 32,000 cars off the road. It also projected that SESI would save the university $420 million over 35 years compared with building a new cogeneration plant.

Water savings matter in California too. The 2015 feature estimated that SESI would reduce total campus water use by about 15 percent. The SESI site reports an 18 percent drop in potable water use in the first year and more than 70 percent average annual water savings for campus energy generation.

A decade on, Stanford's April 2025 report said the university had cut its Scope 1 and 2 greenhouse gas emissions by 80 percent. The SESI site gives a figure of about 81 percent.

The solar generating stations

SESI is designed to run on clean electricity. Stanford buys most of it from two large solar plants under long-term power purchase agreements. The plant owners build and run the facilities and sell the power to Stanford at a fixed price.

Stanford says it reached 100 percent renewable electricity in spring 2022, when the second plant came online. Its 2015 announcement of the first plant described a 68 megawatt peak installation on about 300 acres, built with SunPower. The difference from the 54 MWac figure most likely reflects how solar capacity is measured, in direct current at the panels versus alternating current delivered to the grid.

The Palo Alto connection

Stanford's energy plant is a university system, separate from the city-owned utilities that serve Palo Alto homes. Our pages on City of Palo Alto Utilities and the history of the city's utilities cover that other story. The two did cross paths during construction. Stanford's 2015 feature notes that the City of Palo Alto approved an amended agreement that allowed the Central Energy Facility to be built at its preferred site.

The design has also been copied closer to home. Stanford's Redwood City campus has its own Central Energy Facility, which Stanford describes as a smaller version of SESI.

Touring the plant

Stanford says thousands of people from around the world have toured the Central Energy Facility. The SESI visit page offers several options.

1. Self-guided tour: a signposted route around the outside of the plant at 506 Oak Road. A sign map is on the SESI website.
2. Guided walking tour: led by energy industry experts and staff, typically about an hour including questions. Groups are 15 to 20 people. Request one through the SESI site.
3. Virtual tours: a video fly-through and a 3D digital tour for people who cannot visit.

What comes next

Stanford's goal is net zero carbon emissions by 2050. Its 2025 report said the remaining emissions will be tackled by replacing natural gas equipment with heat from SESI where possible, or with renewable electricity where it is not. Campus-wide electrical upgrades are underway and Stanford says it is working with PG&E on more incoming electrical capacity. The research side of the same mission sits in the Doerr School of Sustainability, which hosts the weekly Stanford Energy Seminar.

Frequently asked questions