Santa Rita Jail Microgrid

Santa Rita Jail Microgrid

On Thursday, March 22 2012, Alameda County hosted a grand opening of the Santa Rita Jail Microgrid. The pictures in this gallery were taken at that event by attending Berkeley Lab staff and are freely available for use without restriction.

The project is partially funded by U.S. DOE under its Smart Grids program. The Santa Rita Jail is a ~4,500 inmate facility that opened in 1989 and considered one of the most energy efficient jails in the U.S and has had a fairly flat load and an electricity peak demand of about 3.0 MW.

A 1.2 MW PV system covers most of the cellblocks. When installed in spring 2002, it was the biggest in the U.S. In May 2006, a 1 MW molten carbonate fuel cell with heat recovery providing hot water pre-heating for domestic hot water requirements was added.

A large (2 MW and 4 MWh) Li-ion battery was also installed at the Jail. The battery is equipped with Consortium for Electric Reliability Technology Solutions (CERTS) Microgrid capability, which allows the Jail to disconnect from the grid and run islanded for extended periods. A static switch at the Jail's substation will permit rapid disconnect and reconnect. Note that in this μ⋅grid, the battery represents the only controllable resource, so it must maintain energy balance alone.

Under the terms of the U.S. DOE grant, the Jail must contract with PG&E (the utility company) to reduce the peak load on the local feeder by 15%. Reliability is also a major concern, particularly having enough energy to maintain full service during the break between a blackout beginning and the back-up diesel generators reaching full power, typically a few minutes.

Berkeley Lab used DER-CAM to assist with the selection of a battery vendor. Now the battery is installed, DER-CAM will be used to find optimal charge-discharge schedules minimizing its bill and meeting its other objectives. Note that the optimization is very complex in this case because of the multiple objectives and the introduction of uncertainty in some variables, e.g. neighboring feeder loads and outages. Outages of the fuel cell have a particularly dramatic negative affect on bills. An uncertainty based version of DER-CAM is being developed for just such applications.