This is the fourth article of a five-part series on industrial energy efficiency. This month we cover Part Four of the series: Start-Up Spikes. This occurs whenever energy-consuming equipment and systems are started simultaneously.
Start-up spikes are an all-too-common occurrence in most manufacturing and distribution facilities. When energy-hogging equipment is started up at the beginning of a shift, it can often lead to unintended peak-demand energy charges.
This staging of load ensures that power quality is maintained and any on-site generators are not overloaded during start-up. In addition to the sequential start-up, the load control system would monitor on-site generators, removing power load from the system if the generators become overloaded.
A Case Study
Start-up spikes can sometimes go undetected unless you’re monitoring your energy data. The following situation, reported by Industrial IP Advantage, is a case in point:
A manufacturer’s energy consumption profile documented a significant spike in demand that occurred monthly, without fail, on the same day and at the same time. A submeter pinpointed the source of the spike. During lunch break on the same day of the month, the maintenance staff simultaneously started all of the production equipment for testing purposes.
Staging the start-up – achieving a steady state with one system before turning on the next – would avoid the spike. But the optimal energy management strategy also included scheduling the once-monthly testing at 6 a.m. during the power utility’s off-peak demand period. The bump in overtime costs is minimal relative to paying peak rates over the course of an entire year.
This example underscores the importance of routine energy monitoring, so that start-up spikes can be pinpointed and eliminated before they become a problem.
Up to 20% of total electrical use in certain industries comes from air compression systems. Our last article in this series will address how these systems are prime targets for energy efficiency measures.