San Diego VA Medical Center Uses Super ESPC for Solar Mercury Turbine Beta Test

August 31, 2005

  Photo of the Solar Mercury 50 Turbine at the San Diego Veterans Affairs San Diego Medical Center
  A Super ESPC with Sempra Energy Services enabled the installation of this 4.4 megawatt Solar Mercury 50 Turbine at the San Diego Veterans Affairs San Diego Medical Center

The Department of Veterans Affairs (VA) San Diego Medical Center, one of the leading VA Medical Centers in terms of funded research, is close to completing several projects that will save $1.7 million per year in total energy and operating costs, reduce air pollution, and provide much needed infrastructure improvements. The projects were accomplished using a DOE FEMP Super ESPC contract with Sempra Energy Services. The contract enabled the funding and construction of three energy conservation measures: cogeneration replacement and upgrade, which includes a compressed air system upgrade; chiller replacements and cooling tower addition; and HVAC improvements. Sempra designed and implemented the measures, and will guarantee the energy cost savings during the 10-year term of the Super ESPC delivery order.

For the cogeneration replacement, the VA decided to install a natural gas fired 4.4 megawatt Solar Mercury 50 Turbine beta test unit. This innovative turbine was developed recently by Solar Turbines Incorporated as part of a collaboration with DOE's Office of Distributed Energy/DOE Advanced Turbine Systems Program and several other partners. Their goal was to develop a 21st century turbine that is cleaner, more efficient, and less expensive to operate.

The Solar Mercury 50 utilizes an ultra lean premix combustion system resulting in very low NOx emissions, capable of meeting stringent San Diego air quality district emission requirements for NOx without the use of selective catalytic reduction systems. The recuperator uses a portion of the waste heat in the turbine exhaust to preheat the air supplied to the turbine, resulting in increased electrical generating efficiency and decreased steam production compared to a conventional non-recuperated turbine. The electrical and steam generating capacity of the Mercury 50 are a good match with the electrical and steam demands of the hospital. After about one year of operation, a commercial production unit will replace the beta test unit. If for any reason the Solar Mercury Turbine does not meet the performance, availability, and emission requirements in the contract, Sempra will replace the turbine with conventional natural gas-fired reciprocating engines that will meet contracted requirements.

The Mercury 50 turbine was incorporated via a modification to the original delivery order to replace two conventional reciprocating engine generators originally proposed; the new turbine is less expensive, produces more power, shortens the construction schedule to avoid stand-by charges, and allows for more equipment to be installed. The replacement has also resulted in significant NOx emissions reductions. The NOx Emission Reduction Credits (ERCs) are being sold to Sempra as part of the ESPC project financing.

The turbine has been operational since January 2005, and will avoid utility stand-by charges for the next 7 years. DOE, VA, and Sempra anticipate that the installation will be a showcase demonstrating the Solar Mercury 50 technology.

For more information, please contact Tom Olson, VA Facilities Manager, 858-552-7593 or Tatiana Strajnic, FEMP.