photovoltaic systems

[Covenant]

Like many people I have been a bit shocked by energy price rises and last year stuffed a load more insulation in the loft and have bought some energy saving gimmicks but the bills keep going up......
I would very much like to hear from people who have opted to install a PV system. Benefits, things to watch out for, con-merchants, lets hear it warts and all.

[Reid Malenfant]

Hi Jerry, i don't have one or know of anyone that does. However this doesn't mean i don't know a little about it ;)

We don't get enough sun in all honesty to make it worthwhile even with modern solar cells. Besides which to make it useful to you it needs to be converted to 240V AC. The only way of storing power for night time use is to charge batteries & these will need to be pretty big & need replacing every 5 - 10 years (not cheap either) :rolleyes: You'll also need a big inverter to convert the DC from the batteries to AC that you can use, yet more expense :mental:

In all honesty you'd probably be better off looking at a big Inverter type Heating system which works in a similar way to an air conditioner but both ways. These are pretty effecient & provide about double the amount of heat as a standard electric heater for the same power usage :) They also can cool in summer ;)

Another system uses the difference between the ground & air temperature & again a big compressor to save you a ton of money, though i'm struggling to remember what these are called? :scratch: Put it like this, you'd need a garden as a long pipe gets buried underground :)

It'll come to me so i'll get back to you :cool:

[Reid Malenfant]

Ground Source Heat Pump :)

Google is your friend :eyebrows:

[Covenant]

Thanks Mark, I know a little about the technicalities as I am a commercial energy assessor and air conditioning energy assessor :). I just want to get some feedback from people who have spent 10K plus to see if they are happy with their investment. I suspect you are right about the amount of sunlight although most websites seem to claim that you dont need direct sunlight.
GSHP's are great (but expensive) and better in new built design with underfloor heating.
In my own case I will probably not bother with PV for a few years but will replace a huge area of glazing at the front of my house. When I designed it 20 years ago 16mm timber frame double glazing was a good specification. 28mm argon filled pvc frames would probably be a better use of my pennies especially as some of the wood is on its way out.

[Reid Malenfant]

Well you just need to think about when you are going to use the most electricity in all honesty :eyebrows: That'll be in the evening if you are out at work all day, so you'd be drawing current from the batteries rather than the solar cells. Then of course the worst time of year for electricity usage is precisely when you can the least from the PV system - winter :rolleyes:

It just seems a bit backwards to me that the time you need it least is when it can give the most :doh:

I think the other systems while expensive give much more promise as they'll work consistantly no matter what the weather or sunlight due to differences between ground & air temperature in the GSHP case & whatever it is in the Inverter case :scratch: :lol:

I think if you factor in battery replacement every 5 - 10 years (as they certainly do sulphate up) PV looks very uneconomical indeed. You need to be on the equator in a country that doesn't get a lot of cloud - try a desert :exactly:

[Covenant]

Except that the counter argument (guess on my part) is that you will be feeding more back into the National Grid whilst you are out at work.

[Reid Malenfant]

Yes, but like i have been hearing about some of these wind turbines is they can overproduce (rarely obviously :lol:). If they don't need your power then they won't pay you for it, so i wouldn't go on that bargaining chip if i was you ;)

[Covenant]

Interesting, I didn't know that!

[Macca]

My understanding is that there is no way to feed power from solar cells on your garage roof back into the national grid and that the whole benefit is the subsidy you receive on the estimated power your cells have generated. Is that correct? I also understand that they need to be cleaned regularly (at least weekly) to maintain maximum efficency.

[Mark Grant]

My understanding is that there is no way to feed power from solar cells on your garage roof back into the national grid and that the whole benefit is the subsidy you receive on the estimated power your cells have generated. Is that correct? I also understand that they need to be cleaned regularly (at least weekly) to maintain maximum efficency.


The feed in Tariffs make it worthwhile, energy generated is measured with a separate meter, the amount exported is often estimated at 50% as it saves paying for an approved export meter to be fitted.

It is complicated, but say you have panels that can produce 4000 watts and during the day your house uses 1000 watts, then 3000 watts are being exported to the grid through a grid tie inverter, (no batteries are needed :) )

http://en.wikipedia.org/wiki/Grid-tie_inverter

http://www.reuk.co.uk/Grid-Tie-Inverters.htm

http://www.energyenv.co.uk/MastervoltGridTieInverters.asp



It appears the most profitable way is if you work from home etc and use lots of electricity during daylight hours as you get paid for all you generate at a generous amount on the FIT tariff, and then a 50% export tariff, even if you use all you generate yourself you still get paid apparently :eyebrows:
So not having an export meter can be an advantage in some cases.

Some information:

http://www.fitariffs.co.uk/

http://www.navitron.org.uk/faqdetail.php?id=17

http://www.energysavingtrust.org.uk/Generate-your-own-energy/Sell-your-own-energy/Feed-in-Tariff-scheme

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[Ali Tait]

I heard something on the radio about this last week. I think one energy provider- EON I think - will pay to have the cells installed, but they take the generated energy as payment. I believe you have the opportunity to buy the cells from them for a fixed cost per month, and of course you benefit from the cheap leccy. Not sure sbout the ins and outs of the deal, but it looks like a way to avoid the high cost of the initial purchase of the cells.

[Alex_UK]

I heard something on the radio about this last week. I think one energy provider- EON I think - will pay to have the cells installed, but they take the generated energy as payment. I believe you have the opportunity to buy the cells from them for a fixed cost per month, and of course you benefit from the cheap leccy. Not sure sbout the ins and outs of the deal, but it looks like a way to avoid the high cost of the initial purchase of the cells.

It is EON - all you pay is £99 - BUT you have to keep the system for 25 years, and it is a lease arrangement, so the only way to get out of it is to pay the full value of the system. You'll cut your energy bills by about a third, but the energy company will make way more money out of it over 25 years than you will...

I've had a quote to purchase a system myself, and worked it all out - in my case, a 12 panel system (3000W) would pay for itself in about 6.5years, and even without inflation being allowed for, would make a further £40k profit over the remainder of the 25 year guaranteed period. I'm seriously considering it, shame it looks so hideous!

[Mark Grant]

Useful article on Money Saving expert that has been updated recently:

http://www.moneysavingexpert.com/utilities/free-solar-panels#eon

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[Effem]

I would take all payback forecasts with a HUGE pinch of salt. Even as I write this the government is looking long and hard at the feed in tariffs and it would surprise me not one bit if they reduced or abolished it altogether. They have already slammed the door on farmers leasing out their fields to major solar projects, plus the population is becoming increasingly restless about a big slice of their current energy bills being used right now to subsidise the green energy initiatives - me included.