Next* Magazine, Issue 5 - Chevron

Electrical workers inspect the inside of the 53,000-ton battery container following the equipment lift.
Keeping the Lights on at Santa Rita Jail
Chevron designs and builds one of the United States’ largest microgrids,
demonstrating a new model for power reliability
row of nondescript buildings in the
A dry brown hills of Northern California,
Alameda County’s Santa Rita Jail became
a national model for energy security in
March 2012, when the facility switched on
a “smarter” electrical grid. This microgrid,
which incorporates simplified controls and
large-scale renewable and clean energy
generation with a 2-megawatt-capacity
battery, was designed and built by Chevron
Energy Solutions (CES), Chevron’s subsidiary
for energy efficiency and renewable energy
solutions. One of the country’s largest microgrids,
this is a first-of-a-kind project involving
multiple technologies and partners, including
Chevron, the U.S. Department of Energy
(DOE), the California Energy Commission and
the California Public Utilities Commission.
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“The grid’s large onsite battery is
charged during off-peak times and
discharged during peak times. It has
a very fast switch that enables it to
respond to grid outages in milliseconds
and separate the jail from the utility,”
explained Dave Potter, CES senior project
director for Western Region operations.
“This provides the facility with a selfsustaining
grid that integrates all of the
jail’s onsite generation with energy storage
for uninterrupted power—a critical factor
in such an environment.”
In the event of a disturbance to the utility
grid, the jail can automatically disconnect
from the grid and operate under its own
power until reliable power from the local
utility is restored.
The completion of the microgrid is the
culmination of several projects involving
Chevron and Alameda County that date back
to the 2001 California energy crisis.
In 2002, Chevron’s energy efficiency work
enabled the funding of a 1.2-megawatt solar
photovoltaic system—one of the largest of its
kind at that time—on the jail’s rooftop. Three
years later, Chevron installed a 1-megawatt
molten carbonate fuel-cell cogeneration plant
at the jail, providing both ultra-clean energy
and waste-heat recovery while saving local
government more than $260,000 a year and
benefiting the environment. That project
was followed by the implementation of energy
efficiency and water conservation measures
and the installation of five small wind turbines,
adding to the jail’s renewable energy capacity.
PHOTO: SUZIE SAKUMA