Monitor energy use
There are 3 basic steps you can take to find out where energy is being used in your organisation and how to keep track of it.
There are generally 2 types of charge categories - consumption charge and fixed daily charge. There may be several different rates within these categories.
- Electricity consumption is measured in kilowatt hours (kWh): 1 kWh = 1 unit of electricity
- Gas consumption is measured in either Gigajoules (GJ) or kWh.
Electricity consumption charges
Your electricity bill will show your previous and current meter readings for each rate. The difference between the 2 readings will give you the current month's consumption in units.
Calculate the total monthly charge per rate by multiplying the cost per unit by the number of units.
Gas consumption charges
Your gas bill will show your previous and current meter readings for each rate. The difference between the 2 readings is multiplied by factors relevant to your meter to give you the current month's consumption in units.
Smaller users are charged a fixed daily rate, even if they don't use electricity or gas every day. Larger electricity consumers are charged based on peak demand, with different rates for different time periods and seasons.
Plot your spend
Examine your monthly energy costs for the last 2 years. If you plot them on a graph or table you’ll see your energy use patterns and variations over time. The type and complexity of analysis you need depends on your business. Our page on reviewing historical energy use tells you how to go into detailed analysis.
Find the best energy price
Talk to your suppliers to get the best pricing plan for your organisation. Prices are made up of unit costs and fixed charges. You'll need to know what both are before you decide on the best option, so you can better manage monthly fluctuations.
Monthly monitoring helps you to measure the effect of your energy efficiency actions. The amount charged on an energy bill doesn't always correspond to your actual use. (Some retailers estimate your meter reading every second month.) If you don’t want an estimate, call your supplier with your meter reading.
Once you start monitoring your energy use, you can start thinking about why there are monthly changes and what you can do about them.
Identify energy-hungry appliances
While your energy bills give you a good overall picture of your energy use, knowing where the energy goes is even better.
Data collection and management
Current invoices and metering may be enough, but you’re likely to want more detail and to look at specific parts of your business. You may set up more data collection points, with sub metering for every energy accountable centre (EAC). Or you may want to invest in software or outsource data management to consultants.
You’ll need data on all of your energy inputs. Use whatever tools you need to turn the data into useful information, such as simple tables or graphs, regression analysis, CUSUM, degree-days or production normalising. You may need to look at your consumption of gas, diesel, petrol, coal or wood as well as electricity.