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Energy Supply, Timing, Control, and Backup Efficiencies: Energy Saving Investigation Process

What do the icons below mean?

Much of the data-gathering and fieldwork necessitated by this section should be performed by qualified personnel, who are adept at electrical safety and arc-flash procedures:

  • Brown Icon Carefully select the appropriate utility energy rate for the pumping application. (See Energy and Power Rate Dynamics.)
  • Brown Icon Pumping Selections should be based on unit water costs. Know the Specific Power cost per ac-ft/year, mgd or gpm. Also know the Specific Energy cost per KG, ac-ft, or MG.
  • Brown Icon If it is not an emergency, make all motor operation selections for efficiency rather than economy.
  • Brown IconEvaluate Conventional vs. Off-Peak Pumping in systems using the following criteria:
    • Electrical Power systems size power generating and delivery systems using the same concepts of a water system.
    • Power plants are sized to meet the peak daily energy and power load of their users, even if for a very short time.
    • The art of energy conservation is based on reducing the overall peaking factor of a system, thus reducing peak generating demands, brown outs, rolling blackouts, and minimizing the carbon footprint of a power system.
    • The SMART energy grid is an attempt to reduce adverse peaking impacts.
    • Peak water demands like power deliveries are the most costly.
    • Peaks require the greatest usage of resources.
    • Peak demands rob a system of customer growth capacity – whereas reducing the peak through conservation allows for the economic servicing of more customers with fewer upgrades.
    • Peak demands increase O&M on a system.
    • Peak demands also have a greater impact on the environment.
  • Brown IconEvaluate the pumping plant Load Factor using the following criteria:
    • Load Factor (LF) is a measurement of the amount of time a facility runs during the billing cycle or during the average day. A large part of an electrical bill is the demand or peak power charge, and if a pumping system runs at a high capacity for a short time the peak power (kw) charge is assessed on as little as a one minute pumping period.
    • The Load Factor on a pumping system also has a big impact on monthly power rates.
    • If the pumping system can run longer—say 80% or more of the time, at a lower capacity—the same amount of water is pumped during a day or month, but the peak power charge is much less.
    • LF is expressed as a fractional number or a percent (%), where 100% means the pumps run 24/7, 50% means they run half of the time during the billing period, average day, etc.
    • Most pumping facilities are designed inefficiently to run for short periods normally, around 25% LF or less, and cost considerably more to run.
    • They are also designed so longer run periods are saved for emergencies or build-out.
    • A VFD can have a big impact on Load Factors if run correctly, and can save on motor maintenance and efficiency as well.
    • A small jockey type pump or pumps can also increase the Load Factor.
    • An ideal Load Factor would be 80 percent or above.
  • Orange IconBlue Icon Low Power Factor (as opposed to Load Factor), which is caused by an inefficient pumping system, can also significantly increase electrical inefficiencies and may result in an electrical utility penalty. The power factor decreases as more reactive power is utilized in a system (VARs). Reactive energy can be reduced generally by adding capacitors to a circuit or utilizing VFDs.
  • Blue IconEnergy Savings and a VFD:
    • Besides saving Power in a pumping system as previously explained, VFDs can also be utilized to save energy (kwh). This can be a significant savings in some systems.
    • Many pumping systems are pumping too great of a flow in a restricted piping system and the head losses can be significant, i.e. improperly sized pump to pipe system.
    • Other pumping systems are using a valve to restrict the flow in a pumping system to accomplish the above.
    • Imagine driving down the road at 100 mph, and while keeping your foot at the same position on the accelerator, stopping or slowing down your speed with your brake. You consume the same amount of energy but instead of using it, you are burning it up in your braking system.
    • This is similar to the energy losses in a system that restricts flow with a valve.
    • A VFD can save considerable energy by replacing the valved system or restricted distribution piping. It can run pumps for a longer period at a lower flow (similar to the power savings above).
    • This solution can result in energy savings as well as power savings.
    • VFD’s do not ALWAYS save energy however, and are not always ideal for some pumping systems, namely high head systems which have a large static head to overcome.
    • VFD’s can also add extra heat to a pumping system.
  • Orange IconBlue Icon Soft Start’s or Reduced Voltage Soft Starters (RVSS) can be a viable alternative to a VFD, where a VFD is not an efficient alternative. RVSS reduce the peak loads and stress on a starting pump, and also contain valuable motor energy and power data, which is useful in an advanced SCADA monitoring and control system. They also run cooler and can significantly outlast an across the line starter.
  • Orange IconBlue Icon Regularly review plant Wire to Water Efficiencies.
  • Orange IconBlue IconTest for Harmonics on VFD pumping systems and remedy with properly sized filtering systems. Many newer VFDs come with these features.
  • Orange IconEnsure that plant motor and VFD equipment is properly and efficiently cooled.
  • Orange Icon Have a Back-up Power System program and optimize any generator efficiency. Conserve potential generator use. Generators should start remotely, based upon one of the following selector switch positions in the control system:
    • Auto Lock Out—Meaning that the generator fuel will not be used.
    • Auto Start in Outage—Meaning that the generator will switch on whenever the power goes off.
    • Auto Start Pump Call—Meaning that the generator fuel will only be used when the reservoir calls for water, and the generator will automatically shut off when the reservoir is full. This is designed to conserve fuel during emergency situations. Diversify generator fuels, with some using diesel fuel, and some using natural gas and propane. Have a diversity of types, stationary and mobile, and do not oversize them. VFD pumps take less starting capacity. Some starting capacity can be saved by starting at shut-off heads against a closed valve.
  • Orange IconUtilize Solar Cells and battery (UPS) on SCADA systems to keep the data transmitting during a power outage and protect security.
  • Orange IconImplement security systems to protect water quality and quantity.
  • Orange IconIncorporate energy management and operation of back-up systems into your emergency preparedness and response systems.
  • Orange IconInvestigate using a small solar powered DC/AC well for long term emergency water (if only one gal per person per day), with portable tank if needed. A 10 gpm well, run for 12 hours per day will supply 7,200 people.
  • Orange IconProvide a good backup supply of key equipment to promptly implement repairs and save water, i.e., transducers, SCADA equipment, pumps, valves, repair parts, etc.
  • Orange IconProvide advanced Power Quality Monitoring equipment at pumping plants (on either a per pump basis or per plant basis) to assist in the diagnosis of pump problems, etc.
  • Orange Icon Perform regular Infra-Red (IR) camera tests on electrical facilities to determine any potential thermal electric problems with motors, transformers, breakers, electrical connections, etc.
  • Orange IconBlue IconBuilding and plant design and energy efficiency.
    • Insulation—Concrete is not a good insulator in and of itself. Insulate the outside buried portions with protected insulation. Where above ground, insulate the inside.
    • Lighting—Review HO T5 and LED lighting options. Standardize on one system. Skylights can be valuable in certain situations. Security may be a concern with these however.
    • HVAC—This can be very significant. Electrical resistive heating systems can often have kilowatt loads higher than even some of the pumping systems (3-20kw per heater!). If this is the case, seriously look at other alternatives for heating and/or cooling. A small loop of water run through a coil and
      supplied around a pump system can supply significant cooling potential, and even possibly some geothermal heating solutions. Review shallow geothermal (sometimes referred to as geo-exchange) options where you use the water itself for heating and cooling. See the Water Furnace Systems or some ideas. Review solar thermal systems for day-time heating. These can be coupled with geothermal systems as well.
    • Humidity—Moisture from condensation can be a problem, especially if a pump or plant air is overheated. Review economical humidity control systems. Proper ventilation can be important as well. Air heat exchangers can be used in some situations.
  • Green IconKeep all electrical and control equipment clean.
  • Green IconKeep accurate records for daily, monthly, and annual water use at source and demand facilities, also calibrate to correspond to energy billing periods.
  • Green IconLarge energy accounts should be subscribed with the power company for on-line access, for daily review, reports, etc.
  • Green IconIf you use off-peak power strategies, check utility energy meters regularly to ensure that they are synchronized with the correct time. Always leave a small time buffer on your start and stop times.
  • Green IconExternal Energy Service Provider Strategies:
    • Ensure key facilities are accessible to outside utilities in all seasons to guarantee that meters are read in an accurate and timely fashion and not estimated. Estimates eliminate much of the benefits to off-peak strategies or low load and high load factor strategies.
    • Perform regular utility bill audits. Record and log power and gas consumption data as needed to ensure accuracy in billings as well as facilitating reliable budgetary projections.
    • Graph energy and gas use to demonstrate success of conservation and management strategies.
    • Eliminate small unnecessary or redundant electrical accounts—replace with solar systems if and where feasible.
    • Investigate net metering opportunities on smaller accounts using solar, wind, or energy recovery generation devices or other similar and authorized equipment.
  • Orange IconBlue IconInvestigate the Rocky Mountain Power (RMP) Watt Smart program for possible incentive funding of energy saving and management projects. This requires an analysis—performed and funded by a RMP authorized consultant—but if a real and verifiable energy savings can be obtained, the Watt Smart program will provide financial assistance to achieve the same. These projects can provide a significant savings on high energy projects such as pumping systems as described in this document. Any energy saving project you anticipate should be reviewed with your RMP customer service representative prior to its design and implementation.
  • Green IconPotential energy sources and Net-Metering opportunities:
    • Diesel with Proper Air Quality Equipment
    • Energy Recovery at PRVs, i.e., Small or Micro Hydro, etc.
    • Geo Thermal
    • Natural Gas and Propane
    • Solar Electric
    • Solar Thermal
    • Wind