[andysv1k]

Dont forget me too!

www.frenergy.co.uk

Solar PV is a lot cheaper now than its ever been, but cost reductions have slowed recently due to the chinese manufacturers increasing their costs.

It can be a very viable way of going green, but like Al says, it needs to be in the right place. The trouble is, most commercial locations dont suit solar thermal too well as they either dont use enough hot water to warrant it, water usage patterns dont suit, or the distributed hot water system doesnt lend itself to a system (ie local water heating) For this reason, my view is that PV does then become more practical as a solution than in a lot of residential cases. Im working with a client at the moment who are looking to install PV as much as a green statement as anything else.

Some people frown on this idea, but as long as they have all the info upfront and they are aware of how the system will benefit them (ie probably very little when they are drawing 10's of Kw on each phase) and they are not spending the money and expecting far more than is practical, then hey its another renewable energy system, it WILL do some good, it will pay back (eventually) and its great press for the company.

Andy.

[andysv1k]

Oh forgot to mention, if you are considering any form of solar, you will need planning permission.

a) because its a flat roof
b) because its commercial and there is no permitted development rights

Andy.

[IP2]

Thanks Andy Slightly confused now though, hot water really was not a consideration, I was hoping to use it purely to lower / eliminate (possibly too hopeful there) the amount of electricity we pull from the national grid, am I missing something?

[andysv1k]

Two main types of solar systems, PV, this is the one you are reffering to, it generates electricity by solar radiation exciting electrons on the panel.

the second is more basic, but far more efficient, that is solar thermal, it directly uses solar insolation to heat water.

Solar PV - typically 10-15% efficient
Solar thermal - typically 70-80% efficient (as a system, can be far higher as an individual component, our vacuum tubes are 93% efficient)

Andy.

[IP2]

Aha! OK, I will take a look around your site and do some more reading

[OnlyFair]

Thanks for this thread - some useful info here!

[Dotwhack]

How much to solar panels costs these days? - now I live on the sunny cornish coast, the back of my house is south facing and we have sun all through the day so it might be a good way of reducing our electric bill....

plus - this might seem like a daft question but how long does it store electric for?

[IP2]

Originally Posted by Dotwhack

plus - this might seem like a daft question but how long does it store electric for?

As far as I know, you don't store it as such, if you are producing more than you need it goes back into the national grid and you pay the difference of what you took from the grid, less what you put in.

[Dotwhack]

well during the day I wouldn't really be using it cos I'm out so it would only be powering fridge etc then. But ehwne I'm in during the evening (when the sun has gone) does that mean I'm still using national grid electric and paying??

[andysv1k]

Originally Posted by Dotwhack

well during the day I wouldn't really be using it cos I'm out so it would only be powering fridge etc then. But ehwne I'm in during the evening (when the sun has gone) does that mean I'm still using national grid electric and paying??

If you are considering PV, it would be worth getting one of these...

http://www.ecosale.co.uk/index.php?_...od&productId=4

(its my site by the way, not a hidden sales tactic!)

It will help you get an idea of your usage patterns.

PV cannot store energy by the way, atleast not on its own, you can use it to feed a battery bank, but in most cases this is not financially or environmentally viable as there are efficiency losses, plus batteries only have a relatively short life and need disposing of.

Usually PV is fed straight into the mains grid, for example if you install 1kwp of PV and its generating at its absolute maximum and your house is using 1.5kw at any instant. you would only be consuming 0.5kw through your electricity meter, the rest is coming from your PV system.

Thats a very simplistic view of it but gives an idea of how it works. PV rarely generates its rated power though, it will average a much lower figure over the year.

Andy.