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Energy and Power Rate Dynamics: Energy Saving Investigation Process

What do the icons below mean?

This section describes many of the key energy and power tariffs, regulations, and operational opportunities available to Rocky Mountain Power (RMP) customers. These regulations may be similar to those water utilities which are supplied by local Municipal Power Systems. Check with their local tariffs and regulations to properly review any differences.

  • Commercial tariffs commonly used in the water supply industry (NOTE: Rates can be changed, but not more than once per year):
    • Blue Icon Rate 6 Commercial; medium demand < 1 mw (most common pumping rate).
    • Blue IconRate 6A A commercial time of day energy rate. If you have a low load factor you can save on this rate. It also has an off peak rate built in to it.
    • Blue IconRate 6B The Rate 6 power time of day off-peak rate. Rate 6B has a 12 month averaged minimum kw (look-back), prior to the 6B election. Be careful and practice for a year before electing this rate (try to get on-peak loads as low as possible), or, start a new facility with this rate if you are going to go off-peak.
    • Blue IconRate 8 Large commercial and industrial rate > 1 mw. Slightly lower rates but the off-peak period doubles in the summer months from eight hours to 16 hours per day.
    • Yellow IconOrange Icon Dollar IconRate 9 Large industrial transmission rate. Should be considered if loads are consistently above 1-2 mw. Considerably lower rates and off peak periods are the same as Rate 8, but you need to take the service from a transmission line at the high voltage side, 46kv and above, and you must construct, own, and operate a sub-station.
    • Blue IconRate 23 Small commercial, low demands < 30kw, this is typically the highest unit cost rate for water production.
  • Blue IconOff-Peak Power periods:
    • 11:00 PM to 7:00 AM all year.
    • All day on weekends and major holidays.
    • For Rate 8 and 9 Customers they are:
      • 9:00 PM to 1:00 PM in the Summer Months (May through September).
      • 11:00 PM to 7:00 AM in the Winter Months (October through April).
      • All day on weekends and holidays.
    • Remember that you lose most of the power demand savings if you go on peak for even a minute (except Rate 6A).
  • Blue IconOff-Peak Considerations and Implications:
    • Beware of Rate 6B—with Great Savings comes Great Responsibility.
    • Carefully control water source tests or pump exercise schedules.
    • Check power meter clocks at least annually and provide a small time buffer in your run schedules.
    • Study the Rate Tariffs regularly! They change without notice.
    • Understand the fine print in the tariffs regarding the “Daylight Savings Time” Challenge! This requires several more schedule changes than you think because RMP still programs their meters using the old Daylight Savings Time annual schedules. A mistake here can be costly. The current wording is as follows: “Due to the expansions of Daylight Saving Time (DST) as adopted under Section 10 of the U.S. Energy Policy Act of 2005 the time periods shown herein (Off-Peak) will begin and end one hour later for the period between the second Sunday in March and the first Sunday in April, and for the period between the last Sunday in October and the first Sunday in November.”
  • Blue IconLarger User Implications. The Off-Peak rate for rate 6 and the rates 8 and 9 look similar, but the following needs to be remembered:
    • The Off-Peak periods for the Number 6 Rates (6A and 6B) can never go more than eight hours per day.
    • The Off-Peak periods for the 8 and 9 Rates go to 16 hours per day in the summer.
    • Many pumping systems may need to go partially On-Peak in the peak months to meet the daily and monthly demands of the system when the limitation is only 8 hours per day.
    • If you have the ability to use 1 mw you may want to consider a forced
      change to Rate 8 (pay a large power penalty at first) to enjoy the benefits of a longer Off-Peak summer period (study carefully). This trick would need to be done at least once annually, preferably in the winter months before May.
    • The extended off peak period makes the savings for Rate 8 and 9 larger than may appear, since the Off-Peak periods will likely be maintained in the peak months.
  • A Conservation/Savings Management Cycle (The greater the effort, the greater benefit):
    • Blue IconEasy If you have low LF, (<50%) move to rate 6A.
    • Blue Icon Moderate Stay on rate 6 and Increase your LF or pumping efficiency by:
      • Managing your control scheme better (SCADA).
      • Installing VFDs on pumping systems (RMP may help pay).
    • Blue Icon Harder Move your rate to 6A and shed your energy loads to Off-Peak periods.
    • Yellow IconOrange IconBlue IconDollar IconHardest If you are a large user, move to Rate 8 or 9 and go Off-Peak as much as is possible. Use high pump loads Off-Peak and reduce loads On-Peak with large load factors, and investigate ASR and energy recovery.
  • Yellow IconOrange IconBlue IconDollar IconThe Energy Rate and Load Factor Dynamic:
    • Rate 6A is more economical for a low Load Factor (<50%).
    • Rate 6 or 6B is more economical for a higher Load Factor (>50%).
  • Yellow IconOrange IconBlue IconDollar IconEstimated utility energy reads (where a power utility cannot read a meter due to access or weather conditions) can kill any off peak pumping strategy. They do not account well for uses at differing periods of the day. They also can have an impact on high load factor strategies. If this becomes common, particularly in the winter months, see if a continuous remote read system is available from the utility. It may cost a little more a month but the savings can be much more significant.

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