The five most common solar misconceptions I experience as a solar surveyor
Posted by Gabriel Wondrausch on 17 August 2012 at 10:01 am
Working in the renewable industry can be a challenging experience, particularly over the past six months or so with the confusion surrounding the feed-in tariff. Now the uncertainty has been resolved, it appears the industry is on the up.
However, there are a number of misconceptions about solar PV that are widely believed to be true by the general public, causing understandable hesitation for consumers. Hopefully I’ll be able to clarify five of the most common.
1) If you don’t have a South facing roof it won’t work
It’s true that solar systems work best in certain circumstances: facing due South, 30 degree pitch from horizontal, and with good air circulation etc. But that’s not to say it won’t be worthwhile in other situations. According to industry specific design software; a system facing South is likely to produce around 25% more energy than an identical system with an East or West aspect. In real life this figure can be much less.
Analysing data we collect from our installed systems we can see that over the past six months a South facing system produced 9% more electricity than an identical array that faces East: 1935kWh and 1775kWh respectively. Thin film panels that work well in lower light conditions can also be specified for east or west-facing roofs. An east-facing roof for example, experiences intense direct sunshine during the morning then less intense light conditions in the afternoon once the sun’s position has moved on. These panels take in a wider spectrum of light and are able to utilise the diffuse radiation more efficiently than standard panels. Using this technology instead of the more common crystalline modules can provide you with higher yields in these circumstances.
2) Any shading and the panels will shut down
Although shading is important when considering a system its effects can easily be combated through careful design and specialist equipment. Panels can be arranged into separate strings so that the impact of shading is limited to the modules in that particular series, or even better; power boxes can be used to manage each panel’s output individually limiting the effect of shading just to the module it affects.
3) The financial returns aren’t good enough anymore
Obviously the viability of a system is completely subjective but when considering current returns against say ISA accounts that offer 4% interest, a rate of return of 8-13% doesn’t sound that bad. The feed-in-tariff was originally designed to provide An IRR of 7% and with some systems achieving 15% it is clearly an area worth exploring.
4) Panels will keep getting cheaper
Although we may experience a small decrease in the cost of modules in the future it is unlikely to be anything like the meteoric change that occurred over the past year. Panel manufacturers were forced to reduce their profit margins by pressure from a very competitive industry, during an even more competitive time. The general consensus among industry experts is that panel prices have begun to stabilise and it is now the efficiency field that manufacturers will strive to improve.
5) Solar systems don’t need any maintenance
Maintenance is often overlooked by some installation companies. However, we feel it’s an integral part of the package. Continuous monitoring and care of your system is essential to give you its maximum energy yield and best performance. Through monitoring, potential faults can be pre-empted or quickly identified, minimising their impact on your financial return. It is also important to note that regular system maintenance can be a requirement on manufacturer guarantees and insurance requirements.
By Joe Perry, design engineer; photos SunGift Solar
If you have a question about anything in the above blog, please ask it in the comments section below.
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