Chapter 10 Options

New EMS installation/retrofit upgrade

Energy management systems range broadly in level of complexity. More complex systems have a greater number of “points”—monitoring points (inputs) and control points (outputs)—which typically translate into higher energy saving potential, as well as higher installation cost. More complex systems are more fully automated and require minimal manual adjustment by building operations staff once the systems
are operational.

According to the California Energy Commission, any building with a peak demand over 200 kW should consider employing an EMS.1 Additionally, if an existing EMS is over 12 years old, full system replacement should be considered.2 If a host company currently employs an EMS that has been installed within the last 12 years, it may be advantageous to undertake a retrofit upgrade to a more sophisticated system. A retrofit upgrade can often be accomplished by installing and connecting additional sensor and control points to the existing EMS system and reprogramming the software to incorporate the added equipment. An EMS specialist can advise on the feasibility of retrofit upgrades.

Selecting the correct system for a given building requires considering the needs and capabilities of the company’s operations staff. Clearly, a company should not invest in a system with features it is unlikely to fully utilize. The best EMS for a given company is the system that maximizes energy savings potential per dollar invested. An EMS specialist should present a range of installation or upgrade options
accompanied by estimates of energy savings potential and installation cost. These estimates, along with knowledge of host company needs, can provide the basis for analysis of whether an EMS installation or upgrade is worthwhile and what level of system is best for the company.


Costs and rebates: The cost of an EMS installation or upgrade varies greatly depending on the number and type of sensor and control components installed. Table 10.1 provides a rough estimate of the cost of new systems of varying degrees of complexity. Upgrades typically cost approximately $1,100 per point.3 On a case-by-case basis, PG&E will provide rebates per verified kW of load rediced as a result of an EMS or EIS installation or upgrade.4

Financial case study: In 2002, Swinerton moved into a new 67,000-square-foot headquarters at 260 Townsend in San Francisco. The existing building management system (BMS) was 20 years old and in need of replacement. Swinerton installed a new Emcor BMS with timed start-up and shutdown for lighting and HVAC. The new BMS system also allowed Swinerton to track energy use on each floor separately (sub-metering) and to charge the groups using each floor their true portion of the energy costs. The BMS installation cost $40,000 and reduced electricity and gas costs by 50%, achieving a 1.7-year payback period for the project.5

Financial case study: Until 2001, the 1.4-million-square-foot Hewlett Packard (HP) campus in Roseville, California, was operating an EMS with limited automation, which required labor-intensive manual adjustment of controls in order to curtail energy loads during peak demand events. Using funds available from the California Energy Commission and the local municipal utility (Roseville Electric), HP upgraded its EMS and added additional sensor and control points for ventilation and lighting systems. The changes gave HP the capability to shed 1.5 MW of its 10.9 MW peak demand without disrupting occupants. HP now uses the EMS load-shedding capabilities on a day-to-day basis, saving $1.5 million annually in energy costs as a result. The EMS upgrade cost $275,000, but incentives covered $212,000 of the project cost, giving HP a payback of less than one month on the project.6

Additional information

For more information on EMS installation and retrofit upgrades, consult:
• California E nergy Commission. “Enhanced Automation: Technical Options Guidebook,” Section 5—Energy Management Systems. Accessible at
• California Energy Commission. “Enhanced Automation: Business Case Guidebook.” Accessible at

For more information on EIS and load curtailment programs consult:
• California E nergy Commission. “Enhanced A utomation: T echnical Options Guidebook,” Section 6—Energy Information Systems. Accessible at

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