How can I save energy by looking at my load demand (kW)?


#1

I have kW data in various Excel reports as well as in my energy management software, but I am struggling to get useful insights out of it. Where should I start?


#2

Spreadsheets and energy management dashboards you to investigate Active Power measurements collected from your electrical meters. Active power relates to power delivered in an electrical, mechanical, thermal or any form we want, and can therefore be easily associated to business operations, electrical equipment power activity, space occupancy and so forth.

Sometimes one daily kWh figure does not reflect what’s happening during the day. You need to approach active power analysis with a business-oriented mind, meaning that what you are looking for here are discrepancies between how active power varies over time (i.e. load demand patterns) and how you expect your business to operate:

  • Check overnight demand levels, are they high compared to daily levels? If after hours demand is abnormally high, does it mean that equipment is left on and could be switched off?
  • Identify high consumption start/end hours (when demand starts to increase and decrease), does it match your business hours?
  • Seek down-time periods when demand decreases (e.g. lunch time breaks, week-ends), does your staff operates equipment efficiently by making sure that all that can be turned off is effectively turned off?
  • Keep an eye on unusual demand peaks (e.g. peak at night or drop during the day), what could have caused this, has electrical failed and shown signs of inefficiency?

Examples of what you can discover from the analysis of your load demand variations.

Now that you know how to identify whether your electrical loads operate as expected, you can:

  • Go back to your staff and call for action (awareness campaign to switch off equipment when not in use during breaks, overnight and at weekends)
  • Set up alerts in your dashboard (static alerts or Sentinel alerts) to be notified when abnormal demand is detected
  • Revisit your BMS and timer settings throughout your site to align them with business hours and space occupancy (for major potential savings on HVAC and Lighting)
  • If more than 15% of your consumption is at night (e.g. 11pm-8am) and if you are on a flat tariff, you may consider switching to nightsaver tariff structure with lower rate overnight (but slightly higher during daytime hours). You should first check that you are not wasting energy at night, e.g. equipment & lighting left on unnecessarily etc., and you should seek to reduce your night consumption before considering a tariff change.

Another important feature for you to check is your site’s Maximum Demand (MD), which is the highest level of electrical demand measured during the day. To avoid penalty charges, it is critically important that you do not exceed your Maximum Demand Level (kW). Try to avoid unnecessary usage during the MD measuring periods of the day, and if possible re-schedule tasks outside MD periods and avoid large loads operating at the same time.