Posted on 21/02/2019

At an initial glance, power bills can look a little daunting. But they actually provide some very useful information regarding your power consumption habits. Once you get over the initial shock of the large bold final figure owing, you can take a look through the rest of the bill to figure out what time of day is costing you the most and adjust your usage to compensate.

In this example I’ll be using a bill from Red Energy. Your bill may have a slightly different layout, but each section of content should be easy enough to find.

Estimate or Actual Read

First thing to check is if you have been given an estimate, or an actual read. This is often a little hard to find, but can sometimes explain if you have an unexpectedly high bill. In this example it states clearly next to the “Electricity Charges” shown in an image below that this bill is based on an actual read. If for instance your meter is inaccessible when the meter reader arrives (possibly due to a dog on the premises, or other access restriction) then you may be given an estimate. These are based on historic data, and not representative of your actual usage. Once you get an actual read, any differences should be adjusted on your next bill. If you do get an estimate you can contact your retailer and request a read. However there’s usually a charge involved.

Electricity Charges

The most common tariff is Time of Use metering. This is where we have different charges for different times of day. Peak, Shoulder and Off Peak. Generally speaking this is the most sensible tariff to be on when you have a Solar PV System. If not listed on the bill it should be available on your energy retailer’s website:

So, now that we know when the most expensive part of the day is, let’s compare this to what a solar power system can output:

We can see a good amount of the Shoulder and some of the Peak times where the solar will have a great effect in reducing the overall household consumption.

Total Peak = Over the 91 days there was 46kWh used during the peak period. At 51.6c per kWh the total charge for peak power was $23.74.

Total Shoulder = Over the 91 days there was 176kWh used during the Shoulder period. At 23.0c per kWh the total charge for Shoulder power was $40.48.

Total Off Peak = Over the 91 days there was 199kWh used during the Off Peak period. At 23.0c per kWh the total charge for Off Peak power was $31.04.

Total Solar = Over the 91 days there was 1092kWh of electricity exported to the grid. At the buy-back rate of 11.1c per kWh the total for solar was a credit of $121.21

Green Power Premium 100% = Extra charge to guarantee that any power used from the grid is from renewable sources is $22.31.

Service to Property Charge = An unavoidable charge for having access to the power network is $81.90.

How do I tell how much solar I made?

While the power bill shows you some good information, it unfortunately cannot show you the total output from your solar PV system. It will only show you the Exported Power. So, the more power you have used during the day the less export power you will be credited for. Initially this can be a bit of a worry to some, thinking that the solar output is lower than expected. But perhaps an increase in daytime consumption has reduced the solar export figure. Since the export rate is less than what they charge for both shoulder and peak when the solar is in operation, you are actually getting more financial benefit from using the power rather than exporting it.

Some inverters have built in WIFI allowing you to access production figures. Others have a basic display with a daily counter. If you are interested you can subscribe to one of the paid services such as Solar Analytics that will give you much more detailed information on power consumption and solar production via online monitoring.

Historic Data

There are some other convenient sets of data available on the bill. There will be a historic graph for previous bills. This can assist in determining the difference between summer and winter, or seeing any large changes due to adding different appliances to the house:

In this case we can see an increase in consumption in the summer months most likely caused by use of an air conditioner.

The bill will also give you an idea of where you stand vs the average consumption of other houses in the area. This can be a good gauge of generally how energy efficient your household is.

If you have any queries about what information is available on your bill you can always contact your energy retailer for more information. We are also happy to help decipher power bills to suggest the most appropriate solar or battery system for your home.