Given that the feed in tariff in Brisbane is now a relatively insignificant 8 cents per kwh (and yes, as we discuss on the home page, some of the Queensland energy retailers also offer an additional feed tariff on top of this), solar panel system sizing is now very important to maximise your return on investment. Sates like W.A. reduced their feed tariff over 2 years ago, so they can be used as a model to see how correctly setting the wattage of your solar system can meet your goal of offsetting as much as your power bill as possible whilst making good financial sense in terms of the price you pay for you system and the number of years required to repay that investment in domestic solar.
The argument against large (5 Kwatt as an example) solar systems in a low Queensland feed tariff environment is that if much of the generated solar electricity is not used the the small feed tariff rate you are paid for that power will be relatively insignificant compared to the additional cost to have installed, say, a 5 Kwatt system as opposed to a 3Kwatt system. However, it is important to realise that the cost of those additional panels has also reduced over the last few years, meaning, that depending on the brand and quality of the solar panels installed, the additional 2K watt of panels and commensurately larger inverter required now costs relatively less than 2 or 3 years ago. There is some ‘guess work’ required here. Will solar feed tariff’s payable to Brisbane home owners remain at the current levels into the future – say 10 or 15 years from now? Our guess is probably not. Given that the costs of electricity generation and in particular network upgrades and maintenance will increase significantly in years to come, it is probable (though not guaranteed) that the feed in tariff in Qld. may well increase – so effectively improving the so-called ‘pay back’ period of the system (and additional cost IF you install extra solar capacity, above what your daytime electricity usage dictates).
Air Conditioning and Solar Power in Brisbane
The other commonly discussed factor in Brisbane solar system sizing is related to air conditioning in usage in Brisbane homes. Given over 70 percent of houses in Brisbane have air conditioning installed, to cater for the often sweltering high 30 degree Celsius summers experienced in Brisbane, there is a reasonable liking for the possibility of being able to run a fully ducted a/c/ system in your home continuously during daylight hours with a large solar system, knowing that the power required to run that system will come predominantly (again, a matter of doing the sums – air conditioning energy consumption minus the power generated, on average, from your solar system) from your solar panels installed on your roof.