Take advantage of short switch-off periods to cut electricity use
Coffee breaks, lunch breaks and shift changes all add up
Late last year, we shared 16 tips to cut electricity use during seasonal down time. It struck a chord with readers and quickly became our most-read Current newsletter articles.
Shutting down production equipment, such as conveyors, pumps, ventilation fans, air compressors and lighting when it's not needed is a smart way to cut electricity use; but what about shorter switch-off periods? Is it worthwhile to switch-off production equipment for as little as 20 minutes to save electricity?
"In some cases. yes," says Jack Young, operational-savings specialist at Panevo – a Vancouver sustainability consultancy. "Shorter switch-off periods, which can range anywhere from 20 minutes to a few hours, can have a positive impact on your power bill. It's one of the most frequent recommendations that we at Panevo make when we do walkthroughs with business customers enrolled in operational energy analytics."
Reaction to short switch-off periods is wide ranging, with the most common concern being a risk to production, says Young. "One of the barriers to adopting short switch-off period is the concern that production will be affected or delayed if equipment needs time to warm-up all over again mid-way through the day. It's a relevant concern.
"However, warm-up time requirements are often overstated for machinery or equipment that use oil, like a CNC milling machine with a hydraulic system or a CNC turret punch. A short break won't allow the temperature of the oil to reduce to ambient temperature. It won't happen that fast."
Another barrier, Young says, is the belief that turning machinery or equipment on/off a few times a day creates unnecessary wear and tear on the equipment itself. "Switching-off industrial production equipment a few times a day won't do damage, especially with machine tools like milling machines and CNC machines. Motors will draw a higher current when starting up, but this typically lasts only a few seconds and won't affect the facility peak demand, which is charged on a 15-minute rolling average."
With these two big barriers addressed, we asked Young for a list of actions industrial businesses can do to take advantage of shorter switch-off periods and weekend shutdowns. Here are his suggestions:
Short switch-off periods
- Walk through your facility and look for production equipment, such as conveyors, pumps, ventilation fans, air compressors and lighting that can be shut down when not needed (i.e., 20-minute coffee breaks, hour-long lunch breaks and shift changes). Switching off unsupervised equipment will result in energy savings and can remove a safety hazard too.
- Do any motors run in idle? They can be turned off when the equipment isn't in use. Good examples are hydraulic pumps and coolers for CNC tables, which can be switched off during short breaks and during machining preparation times (usually without affecting the indexing of the machine). Fans and blowers are also good candidates.
Evening and weekend shut-downs
- With HVAC, limit the use of portable electric heaters and portable fans. Unattended heaters and fans waste energy and are a fire hazard; they can easily be controlled with wall socket timers.
- Install occupancy sensors or timers to automatically switch off lights when a zone or room is unoccupied. Or make this a manual procedure.
- Air compressors are often left on overnight or on weekends when air demand is not required, whether by mistake or by common practice. In this case you're paying to compress air just to meet the air leaks in the piping system. Program your air compressors to automatically shut down during certain non-production hours; you'll reduce the air compressor run hours and maintenance requirements.
- Miscellaneous or non-critical equipment that's left on will contribute to a high evening or weekend baseload power demand. Most facilities have their lowest baseload power demand over the Christmas holidays (you can learn your business' baseload power demand using the data in your MyHydro account.
Compare your usual baseload demand to your holiday (or lowest) baseload demand. It's best practice to maintain a power demand that's as low as possible during the evening and on weekends, as savings here require little effort and really add up throughout the year.
Building strategic energy management into your industrial business practices will save you money. Determining our program eligibility is easy – it's based on annual electricity use. To get started today, read through our energy management program overview.