When it comes to gas and electricity, there are different factors that determines the final bill. Those includes but not limited to the plan you are on, the daily supply charge, the usage charge and the connection fees.

Let's explain those terms one by one

Connection fee: This is a one time fee that you pay when starting the service, the value differs from one compnay to another.

Daily supply charge: This is a fee that you pay on a daily basis regardless of your usage, so even if you don't use the service at all, you will still need to pay the daily supply charge.

Usage fee: This is what you pay for your usage, for electricity it's measured in kwh and for gas it's measure in kjoul, so for example you might pay 38 cent / kwh. As far as I know, the usage fee has three types, fixed rate, time of usage (peak / off peak / shoulder) and two rate , here we will explain the most two common which are fixed rate and time of usage.

Example of a fixed rate plan:

Fixed rate means that your usage will have the same rate regardless of the time of usage, so if you use electricity in the monring, it's the same price as using in the evening, it's all fixed rate, the below screen shot shows a fixed rate plan 

Connection fee: $40.02

Daily supply charge: 92.4 cents per day

Usage charge: 31.9 cents / kWh

Example of a time of usage rate plan

Connection fee: $40.02

Daily supply charge: 97.9 cents / day

Usage fee:

Peak 1 pm - 8 pm weekdays (exl public holiday), you will pay 41.8 cents / kWh

Off Peak 10 pm - 7 am + weekends + public holidays, you will pay 17.6 cents / kWh

Shoulder 7 am - 1 am , 8 pm - 10 pm weekdays , you will pay 35.2 cents / kWh

so if you are planning to choose the time of usage rate, in my opinion you should focus on using your heaving electricity usage device such as washing machines , dryers , dish washer during the off peak time ( 10 p.m to 7 a.m), if you can do that, then you might have some saving, otherwise, I would say go for the fixed rate.

I hope this helps