You cannot manage what you do not measure.
Inspired by our last article, you have begun to develop an energy management plan and tweaked your BMS, -the next step is reviewing Energy and Sub Metering.
One of the key things to remember about meters is – they don’t save you one kilowatt of energy, one MJ of gas, or one litre of water – they do however empower you to save. Have a look at this – electrical energy consumption at a client’s tenancy.
What do you see? There is an energy crime being committed and the clues are in the graph. In this instance the biggest crime appears to be out of hours usage. Why is 40% of the energy being consumed when the office is empty? The graph does not tell you why, but it tells you that it is happening.
This particular system has sub meters. So knowing that out of hours consumption is high, we can look a bit deeper. This is a graph of a printer power consumption – at 2am in the morning it is chewing through 1200W of power, despite no one printing.
This client has two of these printers, and both were doing the same. Both could be programmed to shut down when not needed. That’s over 12,000 kWh of wasted energy per annum ready to be saved – and that was only one of the opportunities identified on this site. Of course, it is only an opportunity – it will become a saving once someone acts on the information.
So metering can help you identify opportunities, but the information needs to be relevant and timely to really assist. Analysing monthly energy readings can give you a start – but ideally you want more frequent data. Smart meters are now common in buildings, but many customers with these are unaware that they can ask their electricity provider to send them 15 minute interval data.
15 minute high level data gives you a better picture, but ideally you will want to see where the energy is actually going, and that’s where sub metering come into play. New buildings adopting Green Star, may have sub-meters on major equipment, as well as tenant light and power circuits, but there is nothing stopping someone from retro-fitting meters .
Data gathering by software and hardware systems such as a building management system, Environmental Management System (EMS), Data loggers etc. enables the end user to better collate, benchmark and review energy data. However the data is collected, it needs to be put into context, and it needs to be properly scrutinised.
Gather the clues, interrogate the usual suspects, and don’t be afraid to enlist the services of dedicated energy crime fighters…
Energy crime fighting is something we relish. In our next article we will look at energy auditing, and the use of gathered information to drive efficiency improvements.
Steve Hennessy – National Manager Sustainability
Jag Dhandwar – Senior Advisor