Solar Terminology

Kwh – Kilo Watt Hour – A measure of energy. 1 Kwh is equivalent to the energy needed to run a 1 Kilowatt microwave oven (for example) for one hour. Solar panel systems are typically quoted in terms of their Kilo Watt (Kw) rating – 1.5Kw, 2Kw, 3Kw, 4Kw and 5Kw being the most commonly marketed sized systems around Brisbane for domestic solar installations. Commercial solar systems, for small to medium sized businesses can easily be sized in the 20Kw to 50Kw range. In terms of energy, a 1.5Kw system will produce 1.5Kwh of energy in an hour, a 2Kw solar system 2Kwh of energy in an hour etc etc.

Solar Energy Production – You will often see various solar promotions claiming that a certain system will produce so much energy. It can be confusing. As a guide, you can estimate the daily energy produced by a solar panels system installed in Brisbane by this formula:  Solar System Size (in Kwh) times 4.2 =  Daily Energy Generated by the system. For example;

Solar System Size           Approximate Daily Energy Generated 

1.5Kw                                      6.3Kwh

2Kw                                          8.4Kwh

3Kw                                         12.6Kwh

4Kw                                         16.8Kwh

5Kw                                         21Kwh

The daily usage of energy in Brisbane households can vary from 10Kwh to 60 Kwh per day, depending on appliances used, number of people in the home, home insulation and many other factors. As we state on the home page, the current low feed in tariff environment lends itself to matching the solar system size you purchase to the energy consumption in your home during the time the solar panels are producing electricity.

Inverter or Solar Inverter – An electronic device that converts the direct current (D.C.) generated by the solar panels into the alternating current (A.C.) we use in our homes. Inverter technology has become extremely sophisticated in the last 4-5 years and inverter  solar inverterefficiency ( the percentage of the power from your solar panels that is converted into usable A.C. electricity) has increased to the high ninety percent mark. Modern inverter design is generally ‘transformerless’, meaning less power loss and probably reduced manufacturing cost. Many Brisbane solar panel installers use reputable brand like SMA (pictured) or Aurora (we have no affiliation with either company).

Solar Racking Solar Panels are attached to the roof of your home through solar racking systems. As with inverters, solar raking has actually become ‘smarter’ in terms of its design, functionality and ease of use and installation. Racking is(or should be) supplied according to your homes specific requirements and may be a metal roof racking system, adjustable tilt system (to ensure the pitch of the solar panels provides maximum electrical output – often used on flat or low pitch roofs) etc. Racking is generally specified in terms of :

Standards Compliance (AS/NZS) etc

Maximum Wind Speed Rating

Material

Snow Load (possibly not so important in Brisbane!)

Warranty (minimum 10 years)

solar cells - how solar panels work

Individual solar cells combined together make up a solar panel

Solar Panel The fundamental operation of a solar panel comes back to understanding some basic semiconductor physics. No, dont be scared off by this – its fairly simple to understand. The heart of a solar panel are its solar cells – silicon ‘wafers’, sliced from a large ‘rod’ of very pure silicon. The silicon cells (many of which are wired together and encapsulated in the finished solar panel) are engineered in such a way that when sunlight strikes them, a flow of electrons (the basis of electricity = electron flow) is created. The amount of electron flow, or solar electricity, is directly proportional to the amount of sunlight received incident to the solar panel, which is why the correct orientation of the solar panel and the correct pitch of the panels is critically important in ensuring the maximum amount of electricity from the panels. The often touted ‘efficiency’ of the solar panel is simply a measure of how much electricity a solar panel outputs for a given amount of sunlight received by the panel. As a rule of thumb, 1000 watts of sunlight hit one square metre of earth under optimum conditions. So, if it were possible to construct a perfectly efficient solar panel, then a 1 metre square solar panel would generate 1000 watts of power on a sunny day. Current solar panel efficiencies used in a Brisbane solar installation, will range from around 14 percent up to close to 20 percent for the highest specification panels, meaning for every one metre of solar panels installed, you could expect them to output around 140 watts of solar power up to 200 watts, under ideal conditions.

Solar Feed In Tariff

A solar panels system generates electricity – the amount of electrical energy produced is dependent on many factors outlined on the Solar System Efficiency page. Because Queensland operates on a ‘Net Metering ‘ arrangement the way a typical Brisbane solar system operates is that the solar electricity produced by your system is first used within your home. Any excess electricity from your solar system that is not used by your home is then fed back to the electricity grid and your power bills are credited at the rate of: Credit = feed in tariff rate x KWh’s of electricity sent back to the grid from your system. Talk to your energy retailer to find out the exact methodology they use for payment of this credit.