I was looking at pricing on the web recently and a typical 1-1.5KW PV system was quoted at £8500 installed. That system might provide 20% of my electricity... But then I worked out that £8500 could be used to pay the green tarrif rate on ALL my electricity for around 20 years at todays rates. That would seem to be a better deal for the planet.

Apart from obvious things like inflation, am I missing something here?

Is it possible to justify Photo voltaics?

Your quote includes a healthy profit margin for the retailer/installer. That said, pv is expensive because demand is geat and supply is limited. New production facilities are being built all over the world but demand is growing faster. In Germany the government has 'feed-in tariffs' that require electricity companies to pay you for your surplus power at a pretty generous rate. This makes installing domestic pv in Germany much more attractive.

Here are some good real world figures for a 1.8kw peak system - http://www.solarious.co.uk/PVSolar.html - they are getting around 1600kWh per year.

So with a grant you might get around £160pa of electricity for around £6000 spent. So although not particularly great in payback terms, at least it is the same ballpark as simply investing the money in the bank. It does seem that if the price of solar PVs continues to drop, than it could become a very good option. Think i read that US prices are around $4 per peak watt and if it can get down to $1 per peak watt then it become cost effective energy generation. Some predictions put us only a decade away from $1/watt.

But as skywalker points out that money might better buy you things to reduces your energy consumption. Consider the best energy efficient products ("The latest fridge could save two thirds of the energy used by a ten year old fridge, which adds up to about £35 a year" - www.uk-energy-saving.com). Maybe solar hot water would be worth considering.

Just now it's hard to buy 100% green electricity because demand is greater than supply. It's best to buy electricity from Ecotricity as they are the only firm that both retails electricity and is a 100% green generator. They sell more electricity than they generate but the profit they make is invested in building more turbines.

It is doubtful whether the price the customer pays for solar pv will come down much in the near future. Although production costs are falling as the technology improves and factories are integrated and scaled up, demand is going to remain higher than supply. It's like oil that only costs $20 a barrel to produce but sells for $90. We are working at the limit of production capacity.

The green tariffs are generally less beneficial than they would make you believe.

All electicity suppliers are obliged to source 10% of their production by 2010, with a phased target up to that point. If they do not they have to pay a penalty or they can transfer excess renewables generation by buying ROC's(Renewble Obligation Certificates). As you can imagine suppliers like Good Energy have rather more ROC's than they need. So what they do is sell the excess for something like 4.5p/Kwh. I understand that they currently sell about 95% of their ROC's.

The net effect therefore of buying from Good Energy is very little as they will effectively sell their ROC's and reduce the need for other suppliers to generate their own renewables.
If they didnt do this they would have to charge about 15Kwh for their electricity which no-one would buy.

Therefore I cannot see any benefit in buying from Good Energy as it does not increase the market for renewables.

I do not know of any supplier that sells green electricity that is genuinely increasing the supply of renewable electricity which would not have happened anyway under the renewables obligation.

For that reason if you want to improve things over and above the renewables obligation you have to do it yourself.

>I do not know of any supplier that sells green electricity that is genuinely increasing the supply of renewable electricity which would not have happened anyway under the renewables obligation.

Then you don't know Dale Vince and and his firm, Ecotricity.

Posted By: biffvernon>I do not know of any supplier that sells green electricity that is genuinely increasing the supply of renewable electricity which would not have happened anyway under the renewables obligation.

Then you don't know Dale Vince and and his firm, Ecotricity.

Yes I do actually as I transferred my supply from Good Energy to Ecotricity a couple of years ago.
They are indeed the best of the bunch. Although they dont supply 100% renewables they are investing in more capacity.

However I stand by my view that this capacity increase is driven more by the Renewables Obligation than anything else.
The economics of wind do not stack up without the Renewable Obligation and very few would be prepared to pay 15p/Kwh.

We need more people like Dale - all credit to the man.