Solar Panel Guide Discussion

jgrove_2

wotadeal wrote: »

To invest £12000 in solar panels in order to get back £25 x (1030+70)=£27500 gives a return of 3.37% APR which is not particularly good. It would be more cost effective to invest your money in a fixed interest, fixed rate savings account and save the cost of maintenance/repairs on a solar power system that will undoubtably fail at least once in the next 25 years.

If i had 12k in the bank i wouldnt worry about a solar pv system! Like many i would borrow the money against the house in order to have it fitted, for me it seems the best way to help avoid the increase in fuel costs over the next few years, and also to teach my children that there is other ways to get energy and that we can use 12v applainces that run fine of solar pv.

voyager50

Wow that stirred up a few replies.

1, Tank is free, left over from expensive new boiler fit, immersion heater obtained cheaply from boatyard. If I get some hot water any time of the year then its a cost saving on the gas which is not getting cheaper.

2, Kitchen refit is a must anyway and my wife hates the gas ring, takes too much cleaning and again any cooking done during daylight is likely to be cheaper than the gas. Oven and micro are already electric anyway.

Oh and I do like salads

celerity

voyager50 wrote: »

1, Tank is free, left over from expensive new boiler fit, immersion heater obtained cheaply from boatyard. If I get some hot water any time of the year then its a cost saving on the gas which is not getting cheaper.

The cost of electric isn't getting any cheaper either, and if you're not careful, you will end up paying for it when you forget your immersion is on and a cloud goes overhead.
Like I say, a 1.25kW immersion would be manageable (a 3kW one wouldn't in my opinion) but the more standby energy your house uses the harder it will be to run for free. eg: if your house uses 400W you'd need your panels to be kicking out 1.65kW. In the summer I can vouch that you will have many happy hours generating much more than this - in the Autumn and Winter... I don't know...
I agree it's worth a shot if you got the heater cheaply though, good luck!

voyager50 wrote: »

2, Kitchen refit is a must anyway and my wife hates the gas ring, takes too much cleaning and again any cooking done during daylight is likely to be cheaper than the gas. Oven and micro are already electric anyway.

This makes me very upset. I'm a keen cook that likes to use *flames*, and am stuck with using electric as we have no mains gas here. You don't know how lucky you are!

In all seriousness though, I'd check your figures - electric hobs can easily use 5kWh and for much of the year your panels are going to be giving out way less than their peak output. For example, for most of yesterday I was generating a derisory 200W from my 3.91kWp array (heavy rain all day).
Don't get me wrong, I'm thrilled with my panels, and so far they are preforming 30%+ above prediction, but you can't possibly plan your life to only cook when you are generating say, more than 2kW - it just isn't possible (well, not for me anyway, but then I hate salads ).

/\dam

K4blades

zeupater wrote: »

Hi

I've already queried the EST use of 'significantly more'. This is possible, some with atypical consumption will achive 'significantly more' because they use 'significantly more', however, this will be related to a significantly higher baseload.

It is a fact that my household displaced imported energy savings from a 4kWp system are higher than £100/year, but not significantly higher, and believe me, this is only possible through being at home in the daytime ..... this, in my case, is a fact. Is it possible that you could inform everyone of the facts on how you save 'significantly more' than this figure from your installed system ....

I have been following the continual references to SAP software when relating to the potential imported electricity savings and I must say that the SAP figure is wrong, it was wrong when I had quotes for my system and the more informed installers agreed it was wrong, it's also known to be wrong by the BRE as evidenced by their own documentation .....
http://www.bre.co.uk/filelibrary/SAP/2009/SAP-2009_9-90.pdf

Quote : SAP 2009 version 9.90 (March 2010) - Appendix M1 (Page 82)

'Electricity exported is valued at the price for electricity sold to the grid. The

effective price depends on a factor, b, which

is in the range 0.0 to 1.0 and is defined as the proportion of the generated electricity that is used directly within the dwelling. The value of b depends on the coincidence of electricity generation and electricity demand within the dwelling. At present the value of b = 0.50 should be used for SAP calculations: this will be reviewed in future if relevant data becomes available.'

This method of calculation is based on too simplistic an assumption, being that 50% of generation is used in the property, whatever the size of array is installed and is therefore flawed, and is therefore wrong. The BRE obviously understand that it is wrong, effectively qualifying their position by saying that the 50% factor is not based on relevant data because none is available.

If someone is considering various size arrays all capable of producing 850kWh/kWp then the SAP assessment calculation would say that they could reduce their energy usage by 1500kWh with a 3.5kWp system, 3000kWh with a 7kWp system and 6000kWh with a 14kWp system, which is so obviously impossible when the actual energy consumption could be literally anything .... remember, SAP is a 'Standard Assessment Procedure' for comparing properties in a standard way, which due to actual individual (unstandard) energy usage patterns is unlikely to reflect reality.

HTH

Z

I don't think BRE are saying the 50% figure is wrong as such, simply that at the time of development of SAP calcs, there was insufficient evidence of any other figure, so this figure for now has become accepted within industry.
As the number of installations grow, accurate data will help to improve SAP, but SAP and more so RDSAP, is not a great measure of PV benefits, not so much because of its "standard" approach, but because it does not really consider all electrical use in a dwelling, just heating / lighting / ventilation.

And one of my reasons for visiting these forums is to develop my own personal knowledge based on as many as possible real life situations, like I said, the bigger the data set, the better.

But the point of my post that you seem to have selective quoted / edited was that digitaltoast said "the best saving you can hope for is £70.00" Would you say this comment is true or false, based on your installation and evidence from others. You seem to question what is meant by "significantly better", what I would say is that IMO, £70.00 is not the most you will save.
Agree or not?

tightperson

Hi,

I have read a fair bit about the pros & cons of PV systems & also the unhappy people who can't afford one, dislike where the money is coming from & all the other arguments.

I have been interested at looking into a PV system for some time & would like some answers to some questions please & I am not too clued up. We have had various offers through the door. Tesco have just sent us 10% off if you buy before x etc. I like the idea as I see it as being green & as long as it pays for itself & effectively provides an annual saving that's ok.


1) We have a large dormer loft conversion on the rear which covers most of our rear roof so this is virtually flat roofed. Is it possible to fit panels to a flat roof (subject to it being able to support the weight).

2) Would a portion of our now loft room have to be boxed off to house an inverter & any other bits.

3) If we had some panels fitted to the front elevation & some to the flat rear roof & possibly some to a pitched stand alone double garage to maximise different periods of the day/time of year would that cause any problems other than additional cost.

4) If we sell some collectibles & assets we could just raise enough to buy a PV system.

5) We have been here 10 years but may only stay in this house for a further 5 to 8 years. Is it worth doing?

6) Or would we be better not bothering & Just wait until we move in 5 to 8 years then look to build an eco home or buy something suitable with land for water harvesting, heat pump tech/wind/PV to be used.

Thanks.

RenovationMan

voyager50 wrote: »

Wow that stirred up a few replies.

1, Tank is free, left over from expensive new boiler fit, immersion heater obtained cheaply from boatyard. If I get some hot water any time of the year then its a cost saving on the gas which is not getting cheaper.

2, Kitchen refit is a must anyway and my wife hates the gas ring, takes too much cleaning and again any cooking done during daylight is likely to be cheaper than the gas. Oven and micro are already electric anyway.

Oh and I do like salads

We changed our old gas hob to an induction one. It's only on when the pan is actually on the ring which is safer with kids as well as more energy efficient. Plus we don't have any worries about carbon monoxide.

rhiwfield

tightperson wrote: »

Hi,

I have read a fair bit about the pros & cons of PV systems & also the unhappy people who can't afford one, dislike where the money is coming from & all the other arguments.

I have been interested at looking into a PV system for some time & would like some answers to some questions please & I am not too clued up. We have had various offers through the door. Tesco have just sent us 10% off if you buy before x etc. I like the idea as I see it as being green & as long as it pays for itself & effectively provides an annual saving that's ok.


1) We have a large dormer loft conversion on the rear which covers most of our rear roof so this is virtually flat roofed. Is it possible to fit panels to a flat roof (subject to it being able to support the weight).

Yes, but thye would need to be mounted on a frame to face to the sun and you may need pp. Take care of who you get to install and the specifications of panels, inverter and fittings..

2) Would a portion of our now loft room have to be boxed off to house an inverter & any other bits.

Up to you, but inverter has to go somewhere, ideally accessible and will need ventilation

3) If we had some panels fitted to the front elevation & some to the flat rear roof & possibly some to a pitched stand alone double garage to maximise different periods of the day/time of year would that cause any problems other than additional cost.

You would prob need an inverter for each mini string. I've got 4 x Soladins for my house array, so thats 1 inverter to every 3 panels.

4) If we sell some collectibles & assets we could just raise enough to buy a PV system.

Odds on it will be a better use of your money

5) We have been here 10 years but may only stay in this house for a further 5 to 8 years. Is it worth doing?

Big question. There are very few investments that give a rate of return anywhere near as good as solar pv . But its not yet clear how much value a buyer would put on the income stream

6) Or would we be better not bothering & Just wait until we move in 5 to 8 years then look to build an eco home or buy something suitable with land for water harvesting, heat pump tech/wind/PV to be used.

Up to you again. We've not regretted our pv installations, but first we took all reasonable steps to reduce our carbon footprint. Several of these cost very little and none have adversely affected our quality of life. Personally I'm not a great believer in the "I'll do it tomorrow maybe" approach. Having said that I'm not at all convinced about heat pump technology benefits atm, but we have a rudimentary rainwater harvesting system (linked water butts with hose connections) .

Maybe its more ethical to bring yesterdays housing stock up to todays/tomorrow standards than build new? And the question of value applies to new build as well, will a buyer really pay the cost of say a reed bed system?

Thanks.

Hope this helps!

digitaltoast

tightperson wrote: »

5) We have been here 10 years but may only stay in this house for a further 5 to 8 years. Is it worth doing?

This calculator should give you a very rough guide, it's a bit clunky though, and doesn't take into account the maintenance. You're generally looking at at least 8 years

tightperson wrote: »

6) Or would we be better not bothering & Just wait until we move in 5 to 8 years then look to build an eco home or buy something suitable with land for water harvesting, heat pump tech/wind/PV to be used.

With the exception of the wind part, I'd say yes. From a green perspective, you are ALWAYS always better off saving a kW than generating it. This SHOULD apply financially too. Unfortunately, the grossly distorting effect of the FiT means that this is turned on its head and people are being bribed to be less green at greater expense.

As for wind turbines, unless you have £25k-£27k a large field forget it. As solar PV will not doubt turn out to be, the micro-wind scam turned out to be a complete disaster, with the turbines costing more in electricity to run than they generated! So just beware of that one.

tightperson

rhiwfield wrote: »

Hope this helps!

Many thanks, that's great, that was all the answers I was looking for. Like you say how much value a system will add to the potential sale value of a property is a very hard one to judge especially when no one in our area has one.

My main concern was that our house is not ideally positioned, not south facing, but if they can be mounted on a frame on the flat roof they can be positioned to get their best potential, subject to loadings.

Over the last 3 years we have had our house insulated as much as possible, had low energy lighting fitted, new condensing boiler etc etc so we have gone as far as is practical with all that side of things. We have reduced our footprint overall, gas & electric by about 20%. We still use nearly 6000 KWH per year on electricity though. We have a 4 bed detached with an extra 2 loft rooms. My wife & I due to health problems both now run businesses from home so our electricity consumption is quite high during the day when we would be generating so another reason while I feel a PV system would save us money.

Is it correct I need to get a system fitted before April 2012 in order to get the maximum FIT tariffs & it is likely they will be reduced after that?


#80 digitaltoast

Many thanks for your info. I read your link to the Low Carbon Kid from your previous posts last night & found it most interesting. I actually considered buying a Windsave turbine direct & made enquiries when they first came out but although I am not fully clued up tech wise on these things at the time I could not see how it could generate a sufficient amount to be a worthwhile investment. I then saw them in B&Q & I always wondered what had happened to them. Glad I never went ahead now.

celerity

tightperson wrote: »

Hi,
3) If we had some panels fitted to the front elevation & some to the flat rear roof & possibly some to a pitched stand alone double garage to maximise different periods of the day/time of year would that cause any problems other than additional cost.

Some inverters can handle more than one array. For example I have two separate arrays connected to one SMA 4000 inverter, and if one were to get shaded (although it wouldn't) the other array wouldn't be affected.
I didn't pay any extra for this, as the inverter handles it as standard.

5) We have been here 10 years but may only stay in this house for a further 5 to 8 years. Is it worth doing?

My honest opinion is "no". I personally only advise friends and family to invest in solar PV if they will be staying at their property for twelve years or more (as that is a more realistic payback period).

6) Or would we be better not bothering & Just wait until we move in 5 to 8 years then look to build an eco home or buy something suitable with land for water harvesting, heat pump tech/wind/PV to be used.

It sounds as if you are acknowledging that the eco-potential of your current property isn't that great. I would save your money and look for a "dream property" if I were you. They do exist, I promise you .

/\dam