There are several misconceptions and fallacies relating to the characteristics of PV solar panels and the relative importance of each of these properties. This results in incorrect assumptions and renewable energy investment decisions being made on the basis of incorrect information or on a misunderstanding of the relative importance of various properties of PV solar panels.

When comparing one solar panel with another, there tends to be a strong focus on the panel’s ‘efficiency.’ The rated efficiency of a solar module is however far less important than many would lead us to believe. In short the rated efficiency of a solar module is the ratio of sunlight that is converted into electricity, at one point in time, when the panel is new. This is measured in a lab at ‘standard test conditions’ (25ºC) using a flash of light that lasts for only a fraction of a second. ‘Efficiency’ however, does not tell us how well the solar module will actually perform, i.e. how much energy it will produce, in the real world. Performance is far more important than efficiency as it relates to the amount of electricity generated over time per rated watt of peak output. A more efficient panel does not produce more energy; it simply requires less surface area for a set output. Most crystalline silicon solar panels’ efficiency is quite similar and small differences in physical area are generally not of significance to the customer.

As the energy production of PV modules are affected by a range of factors including light levels, temperature and degradation over time, actual energy performance over time (measured in normalised kWhs / kWP) is a far more useful and valuable measurement than efficiency.

Another myth is that thin film technology is somehow new or advanced when in actual fact thin film amorphous silicon panels have been around for over 30 years.

Recent analysis of the data from the Desert Knowledge Centre in Alice Springs shows that Kyocera Solar Modules are performing better over time than all other modules tested. In addition to this some ‘thin film’ technologies tested, despite good performance initially, have shown significant degradation in performance down to worryingly low levels over a relatively short period of time. The Kyocera panels however have continued to perform well, creating more energy per rated kilowatt than the other panels at the centre. Kyocera has been manufacturing solar for over 35 years and has real world data from their panels over much of this time showing only a very small amount of degradation. See for your self at www.dkasolarcentre.com.au or contact Autonomous Energy on 9907 2466.

Written by Mark Gadd MEM and Matthew Linney Be PV

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