What type of electricity rates & tarrifs are there?
As a general rule there are two primary electricity rate structures offered by power providers; a Flat Rate for each kW/h used (which is the same price 24 hours a day 7 days per week) or a Time Of Use (TOU) rate that varies the cost at different times of the day. Time Of Use rates usually have off peak, shoulder and high peak rates; off peak is typically at night, shoulder during the day until the early afternoon and peak from middle afternoon into the evening. Peak charges can be as high as 50c per kW/h in some areas.
From a solar economics perspective, the results are generally very similar irrespective of whether you are on a Flat or Time of Use Rate. Some electricity retailers only offer you one tariff option, however if your retailer allows choice, you can look at what time of day you typically use most electricity and you may be able to calculate whether being on one tariff could be more advantageous for you. For example, if you come home at 3pm and use a lot of electricity at that time, such as air conditioning and TV, then a flat rate might be better for you. However, if you have a solar system, and better still one with batteries, that is capable of offsetting your own use it may be better to be on a Time of Use tariff.
Like feed-in tariff analysis, your solar system supplier should be able to provide you with an analysis of what tariffs will provide the best outcome for you after discussing your electricity consumption. Some solar meters only offer one option, so it is best to discuss and choose your preferred electricity rate option before you have your solar meter installed.