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Part 2: Evaluating Demand Response Benefits
By James Piper, P.E.
August 2012 -
Energy Efficiency Article Use Policy
The first step for managers determining whether to participate in a demand-side-management program is to bring the local utility company into the process. Programs vary by utility, as do requirements and benefits. To benefit both the utility and the customer, programs must be designed to match the specifics of the facility.
It is essential that the local utility become involved in the process as early as possible. The utility can identify participation requirements, and it is likely to have data on the energy-use and metered-demand levels for the facility for a period of several years. Both items are necessary for managers evaluating the potential benefits of program participation.
The facility's load profile is the first indication of its suitability to participate. Relatively flat load profiles are less likely to produce financial benefits for customers than profiles with a significant difference between peak and off-peak hours. By comparison, load profiles with large variations offer potentially large benefits.
Managers will need to review their facilities' electricity use for a period of at least three years and consider several factors. Is the level of electricity use high enough to warrant participation? Does participation in the program introduce a level of risk sufficient to offset the potential benefits?
The load profile only identifies the potential benefits. Managers also must identify and quantify individual loads the facility can curtail or shift to off-peak hours. Load identification is a two-step process. First, managers must identify and quantify all major electrical loads that contribute to the facility's peak demand. Next, they must evaluate each of those loads for the potential to temporarily interrupt their operation during peak hours or shifting the time they operate to off-peak hours.
The key to successful implementation is participation. Managers who attempt to develop a demand-side-management program without the support of facility occupants are less apt to succeed. When managers attempt to impose programs without first understanding occupants' willingness to participate, everyone becomes an exception. All loads suddenly become critical loads, and rescheduling operations to off-peak hours becomes impossible.
Managers need to involve all relevant parties in this process. Explain the program to them, including potential risks and benefits. The more actively involved facility occupants are, the more likely it is that they will participate willingly and contribute to a facility's success in meeting its goals. Often, they can even help identify additional loads the facility can shed or shift. Designating a staff member for each occupant as an efficiency team leader also can help facilitate the education process.
Once managers have identified the loads, the next step is to develop a plan for shedding those loads in the event of a demand-response event. The amount of time they have to do so depends on the particulars of the program the utility has established.
Facilities that have a building-automation system (BAS) are best suited for participation. The BAS helps managers to identify a number of loads that can be curtailed and to establish a program for shedding those loads. The BAS also can rapidly respond to utility-company notifications. These systems also offer the capability of rotating shed loads so no single load is off-line for an extended period.
If a facility does not have a BAS, maintenance personnel still can shed loads manually. Manually run programs require that managers have a plan to rapidly turn off pre-identified loads at the start of an event and turn them on afterward. If the facility lacks personnel who can respond rapidly, then participation might not be an option.
Part 1: Energy Efficiency: Making Demand Response Work
Part 3: Metering, a Key Role in Demand Response Management