Solar Panel Guide Discussion

digitaltoast

jpmcc wrote: »

Your £12,000 would buy you a 3.5kW(p) system, which if you live in London and have a south facing roof at a slope of 30 degrees, should gain you about £1,500 a year. If you invest that money in a 4% ISA every year and leave it there, then at the end of 25 years you'll be sitting on £66,468. You'll be £34,478 better off.

Ehhhhhhhh? I can't make any of that work out. Where are the calculations for initial investment, replacement costs, inflation etc?

Plugging your figures into http://www.energysavingtrust.org.uk/Generate-your-own-energy/Cashback-Calculator%20 I get a "lifetime income" of £38,828-£12000 = £26828, with the breakeven point at year 8 (excluding all maintenance). Are you sure you've taken into account the loss of investment from years 1 to 8? What am I missing here?

jpmcc wrote: »

p.s. If you have moral scruples about where the money is coming from then you are probably on the wrong site

Well that we can agree on!

celerity

digitaltoast wrote: »

[George Monbiot vs Jeremy Leggett]

I don't have an opinion one way or the other to be honest, I find both of their viewpoints interesting.

Bzzzt! You're comparing chalk and cheese - the list above is ALL renewables. Solar counts for a large part of some items (the subsidies) and a small part of others (the contribution to the grid).

I could try and pretend I was making a wider point about Monbiot's dislike of FiTs in general, but the truth is I made a mistake .
That report is therefore far less relevant than I believed when I posted - that will teach me to post hurriedly in between doing bits of work...

I hope my other counterpoints were of interest anyway.

/\dam

voyager50

Hi I have had solar panels installed for a couple of months now, installed by Homesun, sorry Martin but your information on the buyback is incorrect.

The calculation used is ((303-x)/303)*y where x is the number of months passed from installation and y is the initial cost. Therefore for an inital cost of say £14000+vat the cost at year 13 would be approx £9000. Unfortunately EoN weren't doing them for free when we enquired last year, it took over 6 months to get it sorted out.

I am now installing a hot water tank in the loft with a 1.25kW heater to use some more of the 'free' lekky as well as doing all the washing and drying during the day, I intend to give away as little as possable.
Kitchen refit soon and that will be all electric too to reduce the gas bills, then who knows 12v batteries and lights throughout the house

celerity

digitaltoast wrote: »

I think Graham put [effect of FiT] at around 15% increase on bills. If everyone is shrieking about how the extra 2.5% on VAT (a tax which hits the poor least) will "kill the economy" because of the extra couple of pence on a Twix, imagine what 15% on an unavoidable cost which accounts for the item which hits the poor most, will do.

I'd be interested to see the calculations showing a 15% hike, as I do find that quite high.
That said, comparing it to VAT isn't really fair, as VAT affects virtually everything a family buys in the year.

Try telling cancer research labs/hospitals/teachers that £335 million is not a significant amount. That's a helluva lot of insulation, too.

That's a bit of a cheap soundbite if you'll forgive the observation. Sure, it always emotive to mention cancer and hospitals etc, but you and I both know that £335 million per year isn't a huge amount in terms of the national budget. For example, it would pay for say, five miles of motorway in some areas [a source here]. The education budget is around £80bn, etc etc.
[If I also wanted to indulge in a cheap soundbite, I might mention that we managed to spend £1.5bn for each year of the Iraq war]

Re: insulation, the government is already helping out with this anyway, which I for one am very pleased about (loft was done thanks to subsidies last year, and cavity wall is booked in next month for a mere £99 thanks to Eon).

Anyway, I honestly don't think it's that productive to talk about total cost, as nobody is likely to agree when the figures are so large (in relation to the amounts we personally deal in from day to day) - and I'm of the opinion that lots of it will end up being put back into the economy anyway.

/\dam

jgrove_2

voyager50 wrote: »

Hi I have had solar panels installed for a couple of months now, installed by Homesun, sorry Martin but your information on the buyback is incorrect.

The calculation used is ((303-x)/303)*y where x is the number of months passed from installation and y is the initial cost. Therefore for an inital cost of say £14000+vat the cost at year 13 would be approx £9000. Unfortunately EoN weren't doing them for free when we enquired last year, it took over 6 months to get it sorted out.

I am now installing a hot water tank in the loft with a 1.25kW heater to use some more of the 'free' lekky as well as doing all the washing and drying during the day, I intend to give away as little as possable.
Kitchen refit soon and that will be all electric too to reduce the gas bills, then who knows 12v batteries and lights throughout the house

12v LED's in your house and you'll be laughing they hardly use any power and i intend to use them.

zeupater

K4blades wrote: »

And while we are on the subject of FACTS, this isn't one.
EST said £70.00 was typical but with a larger system could be significantly more.

I don't know if your comment was a genuine mistake, deliberately mis-leading, or an out right lie...but its not a fact!

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

digitaltoast

voyager50 wrote: »

I am now installing a hot water tank in the loft with a 1.25kW heater to use some more of the 'free' lekky as well as doing all the washing and drying during the day, I intend to give away as little as possable.

Ahhhhh...... and what makes you think this will save you money?

http://forums.moneysavingexpert.com/showpost.php?p=43793464&postcount=2561

Indeed if anyone has gas CH and starts using an immersion heater, to use up the generated electricity, they could lose money.

The problem is that some people having got Rent a Roof systems make silly over-estimates of how much they will save - probably they need to convince themselves the gains are higher than they will actually achieve.

http://forums.moneysavingexpert.com/showpost.php?p=44628812&postcount=2762

Like immersion heaters, that can lose you money if you try to use them to 'soak up' PV generated electricity, you would be absolutely certain to lose money if you tried to use storage heaters.

http://forums.moneysavingexpert.com/showpost.php?p=44620354&postcount=2758

People seem unaware that using an immersion heater might 'use up' some of the electricity, however savings can only be costed at gas prices per kWh or off-peak electricity(if you heat water by that method).

Indeed, as explained else where in this forum, using an immersion heater to soak up PV generated electriocity is very likely to result in an increase in expenditure and not a saving.

voyager50 wrote: »

Kitchen refit soon and that will be all electric too to reduce the gas bills, then who knows 12v batteries and lights throughout the house

Well, as long as you only ever plan on cooking in the middle of the day, in the summer, and never in the winter or the evening, and are happy to stop cooking the moment a cloud comes over and for as long as that lasts, then that should work out nicely for you. If I were you, I'd acquaint yourself with raw vegetables, cheese, salad and cold tinned meats real soon.

celerity

Cardew wrote: »

What you have missed is you will save money each year, say, £1000 in the first year.

You then invest this at the same interest rate as you have used above(4% in an ISA).

I took their post to mean they'd already done all those calculations and come up with the figures they gave - they did seem a bit pessimistic though, so I could be wrong.

/\dam

celerity

voyager50 wrote: »

I am now installing a hot water tank in the loft with a 1.25kW heater to use some more of the 'free' lekky [...]
Kitchen refit soon and that will be all electric too to reduce the gas bills,

Please be careful about making these changes - the first one is doable, but will be somewhat tricky to manage (and much trickier if you go above 1.25kW) - the second is just a really bad idea in my honest opinion. Please consider starting a new thread with your calculations on how you think this will save you money, and lots of people on here will gladly check them for you.

/\dam

wotadeal

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.