By Jonathan Marshall
Think of Alameda County’s Santa Rita Jail not as a warehouse for inmates, but as a 21st century energy plant serving a walled town of 4,000 inhabitants, with climate control, a central commissary, a huge laundry, and other energy-intensive services that operate 24/7.
Since the 1990s, with funding and technical support from PG&E, it has undergone a wave of dieting campaigns to slim its substantial energy consumption and save the county money.
By adding a solar system, a fuel cell and by making energy upgrades, the Santa Rita Jail has become a good example of what's possible in making buildings more efficient.
Under the leadership of Matthew Muniz, the county’s energy program manager, the jail has now become one of the first participants in an innovative program administered by PG&E to incent large electric customers to reduce their demand (load) as needed to balance fluctuating supplies of electricity from renewable and other generators.
Muniz and his colleagues have a long history of partnering with PG&E to save Alameda taxpayers money by reducing county energy bills. In the early 1990s, the jail took advantage of a new PG&E energy efficiency program to embark on a major lighting retrofit campaign.
When the energy crisis hit California, the facility erected a 1.2 megawatt (MW) solar photovoltaic system — enormous for its day — on the jail’s roof. PG&E incentives slashed the cost of the final two phases in half.
In 2005, the jail installed a 1 MW fuel cell, also with help from PG&E’s self-generation incentive program, to further reduce its reliance on outside generation. It recycles excess heat from the fuel cell to help power the facility’s hot water system.
In 2008, the jail once again upgrade its lighting, retrofitted its boiler and laundry facilities, and made major improvements in water efficiency, taking advantage of custom rebates from PG&E.
In 2010, with technical help from Chevron and PG&E, and funding from the Department of Energy and California Energy Commission, the jail installed a large battery and energy control system on-site. The resulting “micro-grid” allows the jail to operate independently of the state’s main electric grid when desired.
Now the jail’s latest energy venture is participation in a PG&E pilot program to put cash in the hands of large customers who help the state integrate intermittent renewable energy (solar and wind) onto the power grid by flexibly adjusting their demand.
They do this by making day-ahead bids into the state’s wholesale energy market to reduce their electric demand by as much as 810 kilowatts for periods of one to three hours. The market treats these demand reductions as a valuable resource much like new generation. Knowing when and where to expect these demand reductions, state grid operators can schedule power at the right times to maintain reliable service across the state.
Traditional demand response programs are used mostly during hot summer afternoons, when surging air conditioning loads force utilities to purchase expensive and relatively dirty power to meet peak demand. The new PG&E pilot program makes demand response accessible year round, and encourages creative customer solutions. “This approach could help smooth the integration of more renewable, greener resources, and possibly at less cost,” said John Hernandez, a demand response expert at PG&E.
Santa Rita jail started receiving incentive payments through the new PG&E pilot this February. No one is getting rich—the jail’s take is running around $8,000 a month of late—but Muniz’s staff can manage the online bidding process in less than an hour a month. And simply by adjusting settings on the jail’s battery, they can automatically adjust the amount of energy the facility draws from the outside grid.
“We went into this not knowing what to expect or completely understanding the program, but in first month we realized it was really simple, easy to use,” Muniz said. “It has been a pleasant surprise. We have performed very well so far.”
Email Jonathan Marshall at jonathan.marshall@pge.com.