This breaks down into two smaller steps - measuring your energy use and then finding out where energy might be being wasted.

Measuring

You need to start out by getting the best use from the information from your electricity supplier. You may have data downloads, smart meters or need to take manual readings. Half hourly data downloads give you the most information - if you don't already receive these and have half hourly meters, speak to your electricity supplier.

• Plot the consumption, in kWh, on a graph so you can easily see peaks and troughs. This will help you answer:
  • Is energy use higher than you'd expect outside of working hours?
  • Does the energy use pattern match your production pattern?

For help in doing this, see The Carbon Trust guide How to monitor your energy use (Reference GIL157)

Understanding

Then you need to find out where energy might be being wasted. Common examples are:

• Heating, air conditioning, lighting or equipment being left on in an empty building
• Leaks from compressor
• Shutter doors left open
• Heating too high
• Air conditioning too low
• Doors and windows left open when heating or air conditioning is on - or even having both on together - which happens surprisingly often
• Equipment left idling when not needed

Analysing the metering information will help with this. A walk around survey of your site will help even more.

The Carbon Trust provide free checklists to help you know what to look out for. Two guides you might find helpful are:
Assessing the energy use at your industrial site (Reference CTL002)
Walk around checklist (for printing and paper products) (Reference CTL070)