On Fri, 02 Jul 2010 22:29:14 +0100, Gareth wrote:


David Mackay makes some realistic estimates of the energy you are likely
to get from solar panels he

http://www.inference.phy.cam.ac.uk/w.../page_38.shtml

According to the link below, good panels are ~20% efficient and cheap
ones about 10%.

Most cells supplied in the UK are the Chinese made polycrystalline
sort with efficiencies of around 10-15%. These claim to maintain 90%
of initial efficiency for 10 years, dropping to 80% after 20 years.
Whether these panels will last 20 years is unknown. The only people
who have carried out accelerated aging tests are the likes of BP on
well made monocrystaline panels. Given the volume of panels being
made and the poor quality control on much of this type of production
from China it seems unlikely. Many invertors are also (rather
surprisingly) proving to be very unreliable.

One thing is for sure, it is highly unlikely your supplier will be
around in 20 years - "green" companies fitting solar hot water and PV
seem to be keen to practice what they preach on recycling and
regularly go out of business one day to emerge the next under a
slightly different name as a Phoenix company having shed all warranty
liabilities.