Guest Peter James Posted March 6, 2011 Share Posted March 6, 2011 CliveH - 2011-03-01 7:58 AM and T8LEY - great to see you are in sunny Spain! - how great to see our Spanish friends managing to get panels to generate 24/7 - by way of shinning arc lights at them! (lol) The FIT was so large that they worked out they still made money on selling back to the Government the "green electricity" produced by a panel with an electric light shone on it! How barmy is that? http://bishophill.squarespace.com/blog/2010/4/13/its-true.html Sounds like an Urban Myth to me. As I understand it, the best Solar Panels are only about 20% efficient. Then there's whats lost in the Arc lights. Thats not to say nobody is daft enough to do it.... Link to comment Share on other sites More sharing options...
T8LEY Posted March 6, 2011 Share Posted March 6, 2011 Tracker - 2011-03-04 8:31 PM T8LEY - 2011-02-28 11:39 PM I think the situation is a bit worse than you calculate Tracker. The panels won't be generating 24hrs/day. We get an average of 12hrs daylight/day in a year. So your saving should be halved. . Err no - you misunderstand my calculation! 2kw x 24 hours x 10% efficiency = 4.8 kw per day generated. According to German statistics a 10% efficiency of their PV panel's potential capacity to generate is what they have achieved over the whole country over the whole year so if it's a good enough figure for the Germans it should not be any worse for us - unless we get less daylight or our daylight is the wrong sort of daylight! NPower said they could fit me a 2kw system for a figure quoted yesterday of £8573 which rose overnight to £9295 - hows about that for inflation! Interestingly their projections show the panels at about 9.5% efficient in the UK which is not so far from the German experience. I was agreeing with what you said Tracker but I hope you're not confusing efficiency with daylight hours. The 10% efficiency relates to things such as cloud cover, sun tracking ability, sun angle, conversion rates, maintenance, etc, not the number of hours of daylight. Link to comment Share on other sites More sharing options...
Guest Tracker Posted March 7, 2011 Share Posted March 7, 2011 As I understand it the 10% efficiency relates to the actual power generation percentage achieved of the total wattage potential on any given array. In this case the total potential is 2kw x24h = 48kwh and the 10% reflects the actual volume of the total potential achieved - ie 4.8kw per 24 hour period? Daylight hours, weather patterns, cloud cover, sun angle are all allowed for in the 10% figure and no further allowance is needed because 10% is what is actually being achieved and not a theoretical figure. In simplistic terms 10% efficiency means that the panels are generating 2.0kw for 2.4 hours per day on average over the course of a year. In reality I suspect that they never actually generate 2.0 kw but rather less over a longer period each average day - say 1.0 kw for 4.8 hours per day - to achieve the same yearly total output. Anyway that's how I see it! Link to comment Share on other sites More sharing options...
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