Solar panel performance - The good, the bad and the ugly!

In Australia telecommunications networks have utilised solar power to support critical loads since the early 1970's. These systems have formed the back bone for the powering of major and minor networks ever since. As major long haul, inter capital radio systems were replaced with optical fibre systems, these solar systems continued to support the load requirements without issue. The renewable energy industry will normally showcase the impressive vista of large scale solar installation and compete for attention, but rarely do they show how the panels look after twenty to thirty years once they have been subjected to the elements. This paper is not intended to be a scientific address on manufacturing techniques but a pragmatic review of panel performance. This paper will examine some typical examples of the degradation of two brands of solar panels over their lifetime. The paper provides an insight into when asset owners and operators should consider replacing the panels and if in fact the degradation in output warrants the replacement. Manufacturers will often provide warranties to 80% of rated output at 20 years; so how do operators determine `end of life' and rate efficiency of solar panels getting to 20 years operation - are they able to safely support critical infrastructure? Consideration is given to utilising the legacy solar array systems with “on grid” or “off grid” applications.