20 panel commercial use payback

[Paul2129]

Perhaps the guy that has given me these predictions of total electric generated is a very honest one, after all we're not pointing  in the perfect direction.

     The cost of the install is surprisingly reasonable, and there's an advantage in tax for the business that makes it seem even better..... but if there's one thing I'm surprised at, is that for around 20 to 24 panels, there's so little energy created, probably the value of £250. It just seems so little, or an I being unrealistic ?

     I'm having trouble gathering and using the facts. Good that we're able to use a good percentage of the electric that we make, but it doesn't seem that we can make enough energy to keep a typical electric car charged

 

[binky]

rough numbers, 5000kWh at say 15p per kWh = £750 assuming you use all the leccy generated, we normally work on about 80% self consumption for busines premises. Think he is being a bit pessimistic with the figures - sign of an honest fella.

 

[Paul2129]

The gentleman that quoted had mentioned tonne that the type of tile roof that we have can be troublesome, he mentioned that they can slide out of their own accord and that can be an issue once panels are fitted, also that birds can nest behind. Is it the case that some roofs are unsuitable ? We have no issues with it currently, and providing the installation doesn't cause the problems, I can't imagine issues. Do you have any advise regarding older tile roofs, do solar installations invite roof problems ?

thanks

 

[Paul2129]

Do you think we could see 5000kwh from 24 panels when roughly half are pointing east, and half are on the flat roof, slightly shaded and tipped toward south ?

     I'm north west UK, Blackpool

 

[Barx]

Do you think we could see 5000kwh from 24 panels when roughly half are pointing east, and half are on the flat roof, slightly shaded and tipped toward south ?

     I'm north west UK, Blackpool

No I don't. Not if you go by 'official' calcs anyway, which are the 'guide' figure. Yes these figures are usually on the safe side but:

Let's take that you are going to install the 5.4kWp quoted in the original post:

  For that to generate 5000kWh per year, each kWp of the system would have to generate 926 kWh per year. This number is tabulated in the MCS guide for given areas of the country and for a given inclination and orientation. It is known as the kK factor (kWh/kWp)

  Blackpool drops in the table for manchester which is 7E. Looking at that table, the absolute perfect situation (highest number) would give you 866 kWh/kWp. That is direct south and a 37 to 40 degree incline. So if your 5.4 kWp was facing this way AND had zero shading, you would be quoted 4676 kWh per year.

Now go off to the east by 45 degrees say and that number drops to about 818. Thus if all your system was to point here and NO SHADE. You would be quoted 4417, a fair drop.

At 90 degrees off south then you go down further to about 700 kWh/kWp. Total output would be 3780 kWh per year

I think your installer's number is probably about right to be honest, especially with the shading. Now his quoted usage of that generation could be way off. it's sounds to me like you would use a larger chunk of it and thus more of a saving off your current bill.

Hope that all makes sense. Got a bit carried away.

 

[Paul2129]

You people are smart ! I just sell carpet, that's easy. You reminded me why I don't do electrics

     Thank you for all of your input

 

[Sidewinder]

You people are smart ! I just sell carpet, that's easy. You reminded me why I don't do electrics

     Thank you for all of your input

Hmm,

I had a guy who sold carpet once try to tell me how to fix his machines, and how I was wrong about things, and how his electrical installation was not dangerous, just because it worked.

No test data, or certification to prove that the design was right, or that the installation was done correctly.

Me, I'm still doing the same thing, him, he has a massive carpet store elsewhere, and people working for him now.

So if us sparks are smart, then that is not the be all and end all.

The install was so unsafe, I was on the verge of reporting it to HSE!

However, it would have got me nowhere.

 

[binky]

No I don't. Not if you go by 'official' calcs anyway, which are the 'guide' figure. Yes these figures are usually on the safe side but:

Let's take that you are going to install the 5.4kWp quoted in the original post:

  For that to generate 5000kWh per year, each kWp of the system would have to generate 926 kWh per year. This number is tabulated in the MCS guide for given areas of the country and for a given inclination and orientation. It is known as the kK factor (kWh/kWp)

  Blackpool drops in the table for manchester which is 7E. Looking at that table, the absolute perfect situation (highest number) would give you 866 kWh/kWp. That is direct south and a 37 to 40 degree incline. So if your 5.4 kWp was facing this way AND had zero shading, you would be quoted 4676 kWh per year.

Now go off to the east by 45 degrees say and that number drops to about 818. Thus if all your system was to point here and NO SHADE. You would be quoted 4417, a fair drop.

At 90 degrees off south then you go down further to about 700 kWh/kWp. Total output would be 3780 kWh per year

I think your installer's number is probably about right to be honest, especially with the shading. Now his quoted usage of that generation could be way off. it's sounds to me like you would use a larger chunk of it and thus more of a saving off your current bill.

Hope that all makes sense. Got a bit carried away.

I forgot you're Up North where the sun don't shine. Don't forget to add export rate and FiT  . Front roof does have good pitch and is due south-ish.

Whether on not roof tiles will slip is dependent on age and nails used, as it would appear you have concrete tiles, this shouldn't be too much of an issue - they are only nailed eevry third course normally, they work on their own weight to hold them down.

Pigeons have been known to nest under panels if they can fine a ledge, like a cable entry point, but it's fairly rare.