Alexander Leidinger

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Pho­to­voltaic from the bank (no real ben­e­fit for me)

A while ago I got a mail from my bank. They offer to fund a pho­to­voltaic sys­tem on my house with a spe­cial offer. They give a credit upto a spe­cific amount if I use it to install a pho­to­voltaic sys­tem, and to pay it back I just have to give them the com­plete amount of money which I get from the power com­pany when the pho­to­voltaic sys­tem is pro­duc­ing power (the state requires the power com­pany to pay a spe­cific amount of money — fixed dur­ing 20 years — for each kW/h). They also offer that a spe­cial­ist vis­its me to explain the pho­to­voltaic stuff and cal­cu­late if all the phys­i­cal con­straints for such an instal­la­tion are OK.

At first this sounds nice, but I do not trust the words of some ran­dom per­son which wants to get money from me. So I had a deeper look at it.

The roof of my house is still OK, but in some years (maybe 3 – 5) it has to be changed (at least partly). The roof  is already 30 years old, so this is OK. If I would install a pho­to­voltaic sys­tem now, it would have to be removed and rein­stalled when the roof is changed. If the sys­tem is financed by the bank, this has to be done by an offi­cial spe­cial­ist (instead of let­ting a good friend with expe­ri­ence doing it in exchange of my work­force for some ren­o­va­tion project at his house). This means it would be cheaper if I change the roof before the pho­to­voltaic sys­tem is installed. I do not have the money to do this com­pletely out of my pocket, so the bank has to finance this.

Let­ting the cost of the roof aside (which has to be done “soon” any­way), the inter­est­ing part now is what do I get when the bank is com­pletely financ­ing the pho­to­voltaic sys­tem (maybe parts of the elec­tri­cal instal­la­tion need to get updated, as they are 30 years old too). I have to take into account taxes, what needs to be paid back to the bank, what I have to pay for the power, and what I have when every­thing is paid back.

If the pho­to­voltaic sys­tem is financed com­pletely by the bank, the typ­i­cal cal­cu­la­tion is that it takes about 20 years to pay back every­thing. This assumes I only give to the bank the amount of money I get from the power com­pany for the power of the pho­to­voltaic sys­tem. So basi­cally the pho­to­voltaic sys­tem pays itself. This sounds great, the prob­lem is that a rough esti­ma­tion of the life­time of a pho­to­voltaic sys­tem is 20 years (and after 10 years you may have to change the AC con­verter). The war­ranty on pho­to­voltaic ele­ments here is 2 years, so far I have not seen any offer where they extend it much (some­how it is hard to find some good pages for pri­vate cus­tomers, most of the pages I see are either light on info, or tar­get com­mer­cial cus­tomers). This is not even remotely in the range of 20 years. So after it paid back itself to the bank, it may be bro­ken. And dur­ing those 20 years, I still have to pay my com­plete power bill.

There is also a tax point of view to take into account. Luck­ily a friend of my sis­ter is doing some tax con­sult­ing for pri­vate tax issues. The tax stuff involved here is about com­pany taxes (you are required to open a com­pany when you install a pho­to­voltaic sys­tem here). This is not spe­cially in the area where she is work­ing in, but I assumed she should know enough about the basics, that I can get at least an overview. I got even more than that. When I talked to her about it, she told me they cal­cu­lated a sim­i­lar offer for their house recently. She assumed a pho­to­voltaic instal­la­tion of 20 T€ and that the bank is financ­ing it com­pletely. The roof of their house does not have the same char­ac­ter­is­tics than my house, but as the pho­to­voltaic spe­cial­ists cal­cu­late with rough peak sun­shine hours any­way, it gives me a rough overview. The good part is, that you do not lose money this way, but you have to pay the tax directly (even if I give all the money from the power com­pany to the bank), you start to earn money near the end of the 20 years.

Accord­ing to her cal­cu­la­tions you will have earned 6 T€ after 20 years, when the pho­to­voltaic sys­tem paid itself back to the bank and you had to pay the taxes each month/year/whatever. This assumes that the peak sun­shine hours are not get­ting worse, and that the effi­ciency of the pho­to­voltaic sys­tem stays at roughly the same level dur­ing the 20 years. Now let us cal­cu­late the amount of money per month and per year you gain when you do this:

6000/20 = 300 €/year

300/12 = 25 €/month

So for 25 €/month I have to invest my time into tak­ing care about the tax stuff, have to take care about the pho­to­voltaic sys­tem (clean­ing, and man­age­ment stuff in case some­thing breaks because of bad weather or nor­mal usage), have to pay extra money when some­thing has to be done to the roof, and so on. And when every­thing is fin­ished after 20 years, the pho­to­voltaic sys­tem may be fin­ished too (and the rate of money the power com­pany has to pay for each kW/h then is not known, in case the sys­tem still works good then). If it is in a state where I have to remove or replace it, I also have to pay the cost of remov­ing it. And I need to get together enough money to get a new roof now.

Now this offer does not sound so good any­more (remem­ber, I also have to pay the power I con­sume dur­ing this time). To me it looks like only the bank and the com­pany installing the sys­tem will ben­e­fit from it, and I have to take care about all the unpleas­ant things.

There is for sure an eco­log­i­cal aspect to think about here. It sounds great to pro­duce green energy (I do not know how much CO2 is pro­duced dur­ing the pro­duc­tion of the pho­to­voltaic sys­tem, and if it will pro­duce enough energy to com­pen­sate this), and I would do it directly if I would see a sane return of invest­ment, but this offer does not look sane in my cur­rent situation.

It seems I have to wait until the prices go down more (and I have some spare money to invest with­out the need for a bank). Recently I have read that the expec­ta­tion is that in about 3 – 5 years the tech­nol­ogy to print pho­to­voltaic cells can be pro­duc­tion ready, which could reduce the price to a tenth of what a pho­to­voltaic cell costs ATM. Invest­ing 20 – 30 T€ is not some­thing I would do from one day to another, 4 – 5 T€ for a sim­i­lar instal­la­tion sounds more easy to agree to.

While I am at it: so far I only see pho­to­voltaic info regard­ing the peak power a cell can gen­er­ate. To me this does not look inter­est­ing. The peak power will be gen­er­ated most of the time in sum­mer (direct sun­light, no clouds, long sun­light times), but in the sum­mer the con­sump­tion of power is less than in win­ter (less light to use, more time spend out­side the house so less time in front of a TV, more BBQ so less cook­ing in the kitchen, …). More inter­est­ing to me would be a good power gen­er­a­tion in less than opti­mal sit­u­a­tions like in win­ter when it is cloudy (but it is prob­a­bly hard to come up with an use­ful value, as the aver­age for “less than opti­mal” varies from loca­tion to loca­tion). I have seen a report about water heat­ing (attached to the cen­tral heat­ing) with solar energy, where a sys­tem is used which has a lower peak power, but a bet­ter power out­put in less than opti­mal weather con­di­tions (round col­lec­tors where used instead of flat pan­els). So the­o­ret­i­cally there is the pos­si­bil­ity to get more power out in not so good con­di­tions, but so far I did not find any infor­ma­tion if it is tech­ni­cally pos­si­ble ATM to opti­mize pho­to­voltaic cells to such sit­u­a­tions, and if it is if there are some cells avail­able for a sane price.


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