CHP and PV Increase Power Reliability at Twentynine Palms MAGTFTC

November 11, 2003

The Marine Air Ground Task Force Training Command (MAGTFTC) at Twentynine Palms, California, unveiled a new 7.2-megawatt dual-fueled combined heat and power (CHP or cogeneration) system in February 2003. This project is an outstanding demonstration of the value of CHP for addressing both energy cost and energy security issues at federal sites. The $16 million CHP project, including more than 3 miles of high-pressure gas lines, design, construction, and financing will pay for itself in less than 4 years. In fact, the revenue stream from this project is providing the financing for phase-three upgrades under an energy savings performance contract (ESPC), including a 1.2-megawatt photovoltaic (PV) system, three chiller plants, and several other critical infrastructure improvements.

Photo of heat and power system.

The new 7.2-megawatt dual-fueled combined heat and power system at the Marine Air Ground Task Force Training Command, Twentynine Palms, CA.

In the Mojave Desert 45 miles north of Palm Springs, the MAGTFTC has a twofold mission to operate the U.S. Marine Corps Air Ground Combat Center for live-fire combined arms training that promotes readiness of operating forces, and to provide facilities, services, and support responsive to the needs of tenant commands, Marines, sailors, and their families. Energy security is critical to ensuring readiness of operating forces.

With more than 10,000 military personnel and family members housed at Twentynine Palms, where summer temperatures can reach higher than 120 degrees, a reliable power supply is a necessity, as is cooling indoor environments. The new CHP unit provides a reliable, efficient, secure energy source at a low cost to support the Base's missions.

The CHP system will reduce the Base's need to purchase electricity from the local utility by almost two-thirds, resulting in an annual cost savings of approximately $5.8 million. The savings represent the net effect of reduced electricity purchases, increased natural gas purchases, and maintenance, operation, repair, and replacement costs for the cogeneration system. And in the event of a power outage, the CHP system will provide reliable power to four critical load circuits on the Base using natural gas (or diesel in the event of gas interruption).

The project was accomplished under an energy savings performance contract (ESPC) administered by the U.S. Army Corps of Engineers and the Naval Facilities Engineering Service Center. ESPCs allow federal agencies to fund improvements from guaranteed energy savings and energy-related operational savings. The contract was awarded September 2001, construction began May 2002, and the project was completed in the spring of 2003.

The total cost of the CHP system was $16.2 million and included the construction of a new 7,200 square-foot turbine hall, the 3-mile high-pressure gas line, and all connections to the electrical substation feeding the critical base loads. After generating electricity, the natural-gas-driven hot turbine exhaust is captured in a heat-recovery generator to supply the Base's high-temperature hot water system and to power a 200-ton absorption chiller for turbine inlet air cooling and turbine hall space conditioning. The turbine will provide approximately 30 to 35 million Btu per hour of high-temperature hot water through the heat-recovery hot-water generator. During summer operations the high-temperature hot water produced will power three new absorption chillers, one in each new chiller plant (approximately 1,650 tons of cooling). The system has dual-fuel capability to enable the base to make a seamless switch between gas and diesel if there is an interruption in the natural gas fuel supply.

The project also involves installing new fiber-optic communication cabling to connect the cogeneration plant with monitoring and control equipment at the electricity substation serving the Base. When complete, the overall system efficiency is expected to be 75 percent, 2.5 times greater than the average efficiency of the U.S. electric grid.

The collaboration of many parties contributed to the project's success. The USMC-MAGTFTC, the U.S. Naval Facilities Engineering Service Center, and the energy service company, Johnson Controls, Inc., were primary partners. FEMP took an early interest in the Twentynine Palms project as a showcase for CHP in federal facilities. FEMP helped identify funding for initial design work and provided technical guidance. Southern California Gas completed a preliminary design and feasibility study, funded by DOE's Office of Distributed Energy Resources. Johnson Controls completed final designs, implemented, and financed the project under the Army Huntsville ESPC.

This CHP project is a resounding technical and financial success. It demonstrates the ability of CHP projects to have a broad impact by not only paying for itself, but also by financing renewable energy projects that further reduce peak loads. It also shows how a base-loaded CHP system can be a very cost-effective approach for addressing energy security objectives at federal sites.

For more information, please contact Shawn Herrera, FEMP DER Program Manager, at shawn.herrera@ee.doe.gov or 202-586-1511. For information on the Twentynine Palms Marine Corps Air Ground Combat Center, contact Gary Morrissett, Utilities Manager, at morrissettgl@29palms.usmc.mil or 760-830-5128; or Wayne Hofeldt, Energy Manager, hofeldtw@ 29palms.usmc.mil or 760-830-5128.