# Solar Panels - How long until they pay for themselves?



## BB1977 (Jun 4, 2013)

As per the thread title. 

Do solar panels installed at your house in Spain pay for themselves? How many years approx. does this take? How efficient are they?

Thanks for your help!


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## snikpoh (Nov 19, 2007)

BB1977 said:


> As per the thread title.
> 
> Do solar panels installed at your house in Spain pay for themselves? How many years approx. does this take? How efficient are they?
> 
> Thanks for your help!


I seem to recall a thread on this a couple of years back (at least, I think it was this forum) - have you done a search?

Anyway, when I looked into it, the break-even period was 30 years!

Now I'd love to go green etc. but there is no certainty that one of my children would still be living in our property in 30 years time - so why bother?

Solar systems are so expensive and there really are no grants any more and I think they cancelled the scheme whereby you could feed spare power back onto the grid.


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## gus-lopez (Jan 4, 2010)

It normally works out that the break even point is the same as when they need replacing !!! :rofl:


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## baldilocks (Mar 7, 2010)

On the other hand if you just want water heating, they aren't too bad. Depends on your alternative - we use a multipoint instantaneous gas water heater which, I suppose, maybe costs us about €150 per year to run for hot water (inc showers) for three of us plus two dogs (get a shower once a week) so for us, it would take a long payback time. Of course if you use an immersion heater to keep a damned great tank of water hot all the time, then you'd be quids in


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## snikpoh (Nov 19, 2007)

baldilocks said:


> On the other hand if you just want water heating, they aren't too bad. Depends on your alternative - we use a multipoint instantaneous gas water heater which, I suppose, maybe costs us about €150 per year to run for hot water (inc showers) for three of us plus two dogs (get a shower once a week) so for us, it would take a long payback time. Of course if you use an immersion heater to keep a damned great tank of water hot all the time, then you'd be quids in


They're actually very economical these days - IF you buy a really decent one that is.

We changed from the gas boiler to electric about two years ago. The worst thing was running out of gas half way through a shower - I know I could have put two bottles on but I wanted a better system.


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## bob_bob (Jan 5, 2011)

Going solar is not as easy as you think. You need to look at what you need to power, so no more three TV's, fridge freezer and spare chest freezer in the garage, no electric heating etc, its pretty much a change in life style and you'd need to cut back on your gadgets or certainly think about when you use them a lot more. I've dabbled with solar power and have four panels on my workshop roof in the garden in the UK, I say workshop its more a nice shed but the shed was positioned to get the best sun, the panels charge two deep cycle batteries and allows me to run a small ham radio rig and LED lights....I'll never get my money back in my lifetime but for me it was more a 'fun thing' to do.

I used solar water heating with great success when I had a place on Cyprus and then Portugal and its not that expensive but then your not generating power, more pumping water under glass over a black panel which is heated by the sun.

A good alternative is to look at home insulation,* I mean really look at it* and you'll find its much cheaper than going solar and you will save a lot of money on your heating bill. Also look at LED lighting as they are very frugal on power consumption and have a very long life; you can start using them now.


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## neddie (Jun 11, 2012)

...IMO the only solar devise/system worth anything is solar hot water. This link has a number of ideas for DIY'ers Solar Water Heating Projects and Plans . One doesn't necessarily have to spend a lot of money setting something up 

....regarding solar electric something often overlooked is the cost of replacing batteries.....which will have to be done at some time.


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## Guest (Jun 30, 2013)

neddie said:


> regarding solar electric something often overlooked is the cost of replacing batteries.....which will have to be done at some time.


The upside is that batteries are 100% recyclable.

As an aside, there are two types of electricity producing solar panel installations. One entails many solar panels that fed electricity back into the grid and at the end of the year your usage is compared to your production and you then either pay the difference or are credited to your account.

The second involves electricity producing solar panels batteries recharging batteries.

I worked on an installation of the former in Italy and it did seem it would take many years to recoup the investment - 18 solar panels and a sophisticated control panel... and, there was a government subsidy back then. 

I also worked on installations of the latter on what are called "earthships" - a radical house design built to be as much as possible "off-grid". These systems generally (and I say this with many qualifications) can be built using 4 to 8 solar panels and a small wind generator.

Here is a link to the architect's web site:

Sustainable Green Buildings - Electricity - earthship.com


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## baldilocks (Mar 7, 2010)

mysticsmick said:


> The upside is that batteries are 100% recyclable.
> 
> As an aside, there are two types of electricity producing solar panel installations. One entails many solar panels that fed electricity back into the grid and at the end of the year your usage is compared to your production and you then either pay the difference or are credited to your account.
> 
> ...


It says nothing about the initial cost which will be greater than in the USA due to higher voltages.


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## snikpoh (Nov 19, 2007)

mysticsmick said:


> ...
> 
> One entails many solar panels that fed electricity back into the grid and at the end of the year your usage is compared to your production and you then either pay the difference or are credited to your account.
> 
> ...


Forgive me if I'm wrong, but I think this option is no longer available in Spain.


If I am wrong, can someone please provide some hard facts and links to show what is possible (NOW! not several years ago).

Thanks.


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## Guest (Jun 30, 2013)

baldilocks said:


> It says nothing about the initial cost which will be greater than in the USA due to higher voltages.


I had not thought of that, buy yes a definite consideration. I worked on the initial stages of an "earthship" located a bit south of Valencia. I'll try and contact the owners to find out how they managed this and what costs were involved.

Here is a link to their web site:

http://www.oscarlisabuild.blogspot.com.es


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## Guest (Jun 30, 2013)

baldilocks said:


> It says nothing about the initial cost which will be greater than in the USA due to higher voltages.


Yo Baldilocks, I received a reply: 

"Our electrical system is a typical AC system, we didn't incorporate the earthship DC circuit - it was just too complicated for us as neophytes. We contacted Prosolía, a company based a bit further south and they did the installation for us. We have 8 x 158 watt panels, 12 deepcycle batteries, an inverter and a regulator. This all came to about 14,000 Euros."

I thought most everything was DC here, so I'm a bit stumped by what "too complicated for us as neophytes" means. I'm going to research this more out of my own interests. As someone who would do-it-myself, I reckon their materials would have run about 4.600€, and that's not a bad investment from my point of view.


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## Nugget_Hound (Jun 13, 2013)

Doesnt Neophytes kind of mean amateurs??


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## Nugget_Hound (Jun 13, 2013)

Are you on the grid??


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## Guest (Jul 1, 2013)

Nugget_Hound said:


> Doesnt Neophytes kind of mean amateurs??


Clearly. My curiosity is about if the issue of AC vs DC has something to do with that or something else left unexplained. 



Nugget_Hound said:


> Are you on the grid??


Yes... we're in a 112 year old stone farmhouse... in the process of "reformas".


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## jimenato (Nov 21, 2009)

Oh dear - I'm very interested in this subject but getting a bit lost...

Firstly




> Originally Posted by baldilocks
> It says nothing about the initial cost which will be greater than in the USA due to higher voltages.


I can't see why the higher AC voltages in Europe should involve more cost than the USA.

and



> Originally Posted by mysticsmick
> I thought most everything was DC here,


I don't understand what you mean by that..


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## Hombre62 (Jun 13, 2013)

jimenato said:


> Oh dear - I'm very interested in this subject but getting a bit lost...
> 
> Firstly
> 
> ...


Thanks for highlighting these questions, jimenato. I'm equally confused as to the points being made - the standard domestic supply in the US is 220v, and the standard domestic supply throughout Europe is AC.


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## Nugget_Hound (Jun 13, 2013)

If you are on the grid it would be fairly simple to do yourself , off grid is alot trickier.If you dont use an electric kettle or electric heating/ hot water you could prob get away with a 2-3kw system.


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## Hombre62 (Jun 13, 2013)

Nugget_Hound said:


> If you are on the grid it would be fairly simple to do yourself , off grid is alot trickier.


I think it's the other way around.

An on-grid intertie must be installed by a trained and licenced professional. An off-grid standalone system can be DIY, if it's a low voltage installation.


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## snikpoh (Nov 19, 2007)

Hombre62 said:


> Thanks for highlighting these questions, jimenato. I'm equally confused as to the points being made - the standard domestic supply in the US is 220v, and the standard domestic supply throughout Europe is AC.


Now I'm confused as well.

I thought the supply in the US was 110 - 120 volts? That is 240V coming into the property and then split to two 110 - 120 volt feeds?


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## Hombre62 (Jun 13, 2013)

snikpoh said:


> I thought the supply in the US was 110 - 120 volts? That is 240V coming into the property and then split to two 110 - 120 volt feeds?


My typo. it's a nominal 240V, no longer 220.

You have it right. The standard domestic installation is supplied from a centre-tapped transformer winding at 240V (used for appliances such as dryers, aircon, ovens, etc.). The splits are distributed to the conventional wall sockets at 120V.


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## jimenato (Nov 21, 2009)

snikpoh said:


> Now I'm confused as well.
> 
> I thought the supply in the US was 110 - 120 volts? That is 240V coming into the property and then split to two 110 - 120 volt feeds?


Yes, I was under that impression but I'm ready to admit I might be wrong. But even if the voltage is higher in Europe I don't quite see how that would involve extra cost...


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## Guest (Jul 1, 2013)

Hombre62 said:


> Thanks for highlighting these questions, jimenato. I'm equally confused as to the points being made - the standard domestic supply in the US is 220v, and the standard domestic supply throughout Europe is AC.


The standard domestic supply in the US is AC.

I knew Europe was 220v, but did not know it was AC.

I am just learning the systems and norms here.


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## Guest (Jul 1, 2013)

So, here is what I understand at the moment and it is in regards to an existing building.

Begin with a house that is connected to the national grid. Then, a new system can be installed using solar panels and 12 volt batteries.

The manner this new system is integrated is via a custom electrical panel that allows the house to use the 12 volt DC battery power and allows the solar panels to charge the batteries, and when there is insufficient Sun then the 220 DC grid charges the batteries.

This custom electrical panel would include a DC to AC inverter that outputs 220 volts.


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## snikpoh (Nov 19, 2007)

mysticsmick said:


> So, here is what I understand at the moment and it is in regards to an existing building.
> 
> Begin with a house that is connected to the national grid. Then, a new system can be installed using solar panels and 12 volt batteries.
> 
> ...


I think you mean 220 AC grid - mains supply in most of the world is AC. Batteries are DC so you would have a converter/inverter in the system somewhere.


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## Guest (Jul 1, 2013)

snikpoh said:


> I think you mean 220 AC grid - mains supply in most of the world is AC. Batteries are DC so you would have a converter/inverter in the system somewhere.


Right you are! Thank you for the correction.


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## baldilocks (Mar 7, 2010)

jimenato said:


> I can't see why the higher AC voltages in Europe should involve more cost than the USA.


220/240v versus 110v means greater insulation qualities are needed although lighter gauge wires could be used.


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## jimenato (Nov 21, 2009)

baldilocks said:


> 220/240v versus 110v means greater insulation qualities are needed although lighter gauge wires could be used.


OK, got that. Bit of a toss off between which costs most I would have thought.


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## jimenato (Nov 21, 2009)

Sorry - I meant 'up'.


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