Electric Forensic Pilot Program Completed and Electric Savings Started
In the previous fiscal year, APS launched an energy audit utilizing the three prototype elementary schools for the initial study followed by implementing an energy monitoring program of the District’s top 20 high energy use schools. The international energy conservation consulting company, EnerNOC, provided the cutting edge portable tracking devices that monitor use pattern diagnostics of the HVAC systems, appliances, and technologies in isolating and identifying those that were unnecessarily high energy hogs.
With the pilot completed, addressing the findings began in the 2013-14 fiscal year and is continuing. The APS EnerNOC representative is working closely with M&O in reporting their findings to APS management monthly. Each monthly “scorecard” generated by EnerNOC indicates how every audited system is performing and guides M&O technicians in making the necessary adjustments to offending equipment for optimal performance. The tweaking, from minor to major, reduces the electrical output to reasonable levels.
The initial scorecard provided a summary of savings potential in six areas totaling 100%. Night Shutdown of systems provides the biggest opportunity for savings at 37% followed by High Baseload (daytime) at 23% and Weekend Shutdown of systems, also 23%. Amending the morning Chiller Start-Up of systems from simply flipping an on-switch to a soft start (revving the equipment up slowly) provides a potential savings of 8%. The findings indicate a 7% savings opportunity in lowering Peak Demand electric use during the highest electricity need/use part of the day. This mere 7% in electric savings is deceptive as the cost value of that 7% is many times greater as PNM’s Peak Demand punitive charges are astronomical. Lastly, reducing systems down to hibernation during Holiday Shutdown presents a potential of saving 2% of electricity and is the easiest to do. Should an emergency arise, such as subfreezing temperatures, the systems are programmed to kick in. Though 2% seems nominal, it adds up to a great deal of dollars and kilowatts banked. The chart on the following page indicates an overall potential cost savings of $103,278 in a single year. Next year’s Report will reveal more savings, but to date, the District has realized $50,496 in saved costs and the potential to save an additional $52,781.
The invaluable forensic program has already paid for itself as M&O has been working industriously in making adjustments and comparing the results to pre-adjustments findings. The following graph showcases the tremendous Baseload reduction savings potential ($7,900) at just three elementary schools between July and November
Shutting systems down at 11 schools at night resulted in 613,261 of saved kilowatts at a spared cost of $35,826. Not all adjustments are to equipment, but rather behavioral on the part of occupants and custodians, such as all lights manually shut down at the end of the school day.
The following graph illustrates the percentage increase of electricity saved in December 2014 over the
same month in 2013.
The following examples illustrate the substantial electricity saved in shutting down systems when not in use. In this first example, the black line represents electric use in 2013 and the blue line represents night use in 2014 at Sunset View Elementary over the same few days in both years. The white space between the lines is the electric savings realized in September 2014 over the same days in 2013.
Sunset View Elementary School 12-27-13 — 12-29-14
This next graph represents the holiday shutdown for Rudolph Anaya Elementary School during APS’ Winter Break while school was not in session in 2013 and 2014. The black line is 2013 and blue is 2014. Night shut down was carried out both years, but obviously a much improved process in 2014 saved a tremendous amount of electric energy.
The graph below is a 48-hour comparison between 2013 and 2014. The black line represents a more instantaneous start-up of systems in 2013 and the 2014 blue line shows the improved softer rolling startup, reducing the high spikes and avoiding demand charges due to the lessor surge.
The following graph shows energy savings between the black 2013 line and red 2014 line at Eldorado High School over the same ten days in both years. The white space represents the improvement in energy consumption in 2014.
(See other benchmarking illustrations in the Appendices beginning on page 121.)