Our previous blog, MANAGING YOUR UTILITY EXPENSE: DEMAND CHARGES discussed how managing the energy expense should address demand charges by:
- Gaining visibility of the load profile and to understand which facets of an operation comprise the load and could cause peaks in the demand curve.
- Understanding the utility rate tariff structure and its components.
- Considering energy efficient, low-cost operational practice adjustments that can be made immediately that will have a significant impact on production.
In the industrial sector and even the public and large commercial sector, where over 65% or more of electricity is consumed by motors and motor-driven systems, it is imperative that they be a focus of any demand reduction strategy. This post will focus on what operational changes can be made to reduce maximum demand, while noting that that there is certainly an equipment change out approach to increase the efficiency of the motors and other process equipment that may be contributing to the high-energy use, but as the timing of these capital investments typically are not as immediate, we will address motor efficiency factors in future posts.
How to reduce demand charges
The following are some specific, albeit not all inclusive, recommendations that may help with your motor and driven-system demand management program:
- Establish the facility’s motor and driven system design and load profile so that the high-energy use equipment is identified.
- For water pumping operations (wastewater facilities, pipeline operations, hospitals, and so on), instead of trying to pump all of a material in a short period of time with a high horsepower pump, use a smaller pump and accomplish the task over longer time periods.
- Make sure your motors are correctly sized for the application. Any oversized motor could be increasing your demand and costing you money. It’s also possible that a newer, more efficient motor may be available that would save on demand and energy.
- Make sure pump and motor combinations are the correct size for the system design requirement. Using a 75 hp pump when a 50 hp pump would do the job, results in wasting 25 hp or 18.7 kW of demand. (25 hp x .746 kW/hp = 18.7 kW)
- Make sure that worn pumps, motors, nozzles, and leaks are not increasing flow to the point where demand has increased.
- Be aware of variability in operational demand. Being able to predict future operational demand can result in shifting electricity demand to lower cost periods.
- Be aware of when the billing cycle begins and ends. Running motors and pumps infrequently during a billing period could result in the demand cost far exceeding the energy cost.
- Consider variable speed drives to reduce overall motor operating load. If there is variation in the load, and the motor continues to operate at constant speed, energy is wasted. Process motors, blower fans, condenser fans, evaporator fans, pump motors, and the like can all be candidates for variable speed drives.
These recommendations are certainly helpful but are very difficult to implement and sustain in an ever-changing complex operating environment without the requisite analytics tools. The convergence of Motors@Work understands the critical interdependent factors that are affecting the energy bill, and has the patent-pending analytics to identify and and communicate the actions necessary to reduce or shift the high-energy users to mitigate demand charges. Contact us today at info@motorsatwork.com for more information.