Technical Discussion - PV*SOL Expert 5.5

[Julian Pett]

Here's a great new feature that you couldn't do before:

 

[The Solar King]

Julian

We need far more on the Economic Efficiency Calculation.

People are using this without fully understanding it. Even on the Expert course at Solar Design Company HQ, this was skirted round as the trainers didn't understand it either! I was particularly annoyed with this important aspect of the training. Results are being misinterpreted with people quoting returns far higher than they actually are as they don't understand what the model says. It is possible to use this correctly, IF sufficient explanation is given.

As tariffs are cut use of the economic model becomes more and more important in demonstrating the viability (or otherwise) of an installation.

There are also shortcomings with in it. Unless things have changed in 5.5 you cannot input the export tariff separately from the main feed in tariff. You have to work on the basis of 50% deemed and lump it in together. Hardly satisfactory.

There is also little explanation of the effects paying interest on payment sequences. Also a full explanation of how figures are derived in the final spreadsheet would be very helpful.

Net Present Value and Discounted Cash Flow are not beyond the understanding of the layman. This calculation, and variations on it are used to make investment decisions in all spheres of industry, commerce and Government.

The information and explanation currently available for the Economic Efficiency Calculation is woeful.

 

[Julian Pett]

Solar King,

As you correctly state, with tighter margins, economic modelling is now even more important in demonstrating the viability of an installation.

The Economic Efficiency Calculator in PV*SOL is based on the VDI 6025 Economic Standard and is a very flexible and powerful tool for economic analysis. If you wish to calculate returns from actual use of the electricity generated or to create a ‘deeming’ scenario then it is necessary to define a consumption load profile first i.e. select ‘net metering’ rather than ‘full feed in’

You will then have the option of selecting the British/Italian feed in tariff on opening the calculator and here you can define both a generation amount and an export amount. Alternatively, if you prefer to use a deeming approach, you can simply add half of the export amount to the generation amount and then enter zero for the feed in payment.

The results generated in the PV*SOL Economic Efficiency Calculator gives the Net Present Value (NPV) – the sum of the discounted cash flows of the scheme i.e. the sum of all terms, R[SUB]t[/SUB]/(1+i)[SUP]t [/SUP],where t is the time of the cash flow, i is the discount rate (the rate of return that could be earned on an investment in the financial markets with similar risk); the opportunity cost of the capital, R[SUB]t[/SUB] is the net cash flow at time t. The Internal Rate of Return (IRR) is also calculated – referred to in PV*SOL as ‘Yield’ i.e. the annualized effective compounded return rate or rate of return that makes the net NPV of all cash flows (both positive and negative) from a particular investment equal to zero i.e. Given the (period, cash flow) pairs n,C[SUB]n[/SUB]: NPV = ∑(C[SUB]n[/SUB]/(1+r)[SUP]n[/SUP] from n=0 to N; where n is a positive integer, N is the total number of periods, NPV is the net present value and r is the internal rate of return.

Explanations for all of these terms are available in the Help menu- accessed by pressing F1 at any time.

While it is true that such concepts are not beyond the understanding of the layperson, our experience thus far has shown that few attendees to our training courses are familiar with these concepts. To fully explain this approach to financial modelling would take a considerable amount of additional time and would not fulfil the remit of the training - which is to show how the program works. By the same token, we do not go into the details of the photovoltaic effect (which of course underpins the whole technology) i.e. the concept of a p-n junction and how the carrier flows under equilibrium, short circuit and open-circuit conditions; nor do we examine the theory behind inverter MPP matching and the various algorithms used to ascertain the current which the inverter should draw form the PV array.

We recognise that each individual attendee has a different level of cognisance of the concepts listed above and the course is subsequently tailored to suit this wide range of experience and understanding. We also recommend books and other sources of information to augment the training. Background reading on this and any other taught course is essential to begin to grasp any subject in its entirety.

I will be happy to send you our guide to using the PV*SOL Economic Efficiency Calculator which explains in a little more detail the answer to your tariff query and will hopefully explain to you in clear terms how you can achieve the results you require. Please send an email to [email protected] and we will email this document to you.

 

[Julian Pett]

Don't leave it too late to get PV*SOL 5.5 - the exclusive Electricians Forum offer expires at 5pm Wednesday 7th March - That's tomorrow just before teatime!

 

[Julian Pett]

Follow this link to get a free tutorial on setting up multiple roofs to one inverter in PV*SOL 3D:

[video=youtube;ld5kSskK3Uo]http://www.youtube.com/watch?v=ld5kSskK3Uo&context=C3611e3bADOEgsToPDskIj TI5mHpMHJyPUy3NlDnWC[/video]

 

[Julian Pett]

 

[lspelectrical]

Your post #36 shows a building with split arrays on multiple roofs. Can you send a tutorial for this? Just the main roofs and not the projection.

 

[lspelectrical]

Many thanks for link Julian, but that is not what I am after. I did watch the tutorial, as I thought I was missing something from your instructions. What I actually meant was:

The building shown on this thread (post no #36) has a photograph, a photoplan and a 3d visualisation. What I would like to see is the two arrays on the top roofs of this building linked to one inverter using the 3d visualisation.
I have attached a jpg of the roof in your screenshot and a similar one on pv-sol expert.




I think the tutorial really shows only one roof (albeit different views / sides) linking to the inverter.

 

[Julian Pett]

lspelectrical:

We have created a document showing the steps you need to follow to configure arrays on multiple roofs to one inverter.

These instructions have been emailed to you and are available to anybody else who could use some tips on the subject. If other Electricians Forum members would like a copy of this document then please send an email requesting it to: [email protected] and we'll be happy to provide it free of charge.

 

[lspelectrical]

Thank you Julian. I do appreciate the time you are taking over this.

I have emailed you to discuss.

 

[SolarCity]

Hi Julian,

I wonder if you could explain how to link two buildings together?

 

[SolarCity]

lspelectrical:

We have created a document showing the steps you need to follow to configure arrays on multiple roofs to one inverter.

These instructions have been emailed to you and are available to anybody else who could use some tips on the subject. If other Electricians Forum members would like a copy of this document then please send an email requesting it to: [email protected] and we'll be happy to provide it free of charge.

I wonder if you would mind emailing this info to me also?: [email protected]

 

[Julian Pett]

Hi Chris,

Hopefully both emails have arrived and make sense.

Feel free to email back if you have any further questions.

Julian.

 

[Banguwangi]

I wonder if I too could have a copy of the document
Thanks

 

[hercegovac]

my email is [email protected]

Does anybody have some project or some book for pv? please send to me.

thanks everybody.