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PV*SOL Frequently Asked Questions

Error Messages

Building and site modelling

Configuration

Results

Database Questions

Economic Questions

Error Messages

Building and site modelling

Configuration

Results

  • Where are the results for power clipping or down-regulation found in PVSOL?

    In the 'AC Mains' dialogue, there is an option to set 'Maximum Feed-in Power Clipping' either at the inverter or the grid feed-in point. When this is set, the detailed results vary depending on the settings. In any case the effect can be easily observed for annual values in the Results > Energy Flow graph. Note both options de-rate use the inverter to achieve the export limitation.

    Download the following help sheet 'Power clipping or down regulation by inverter or feed-in point in PVSOL'to find these results.

    See also: How can I model a grid-connected scheme so there is limited or zero export to grid ?

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  • Why do I get such a difference in yield in the simulation of different modules, even though they have the same rated power?

    Usually the reason for that is the part-load operation behaviour of the modules. The specific data for every module are entered in the database by the manufacturers. They have the option to enter a specific part load operation point for their modules in our database; then a specific part load operation curve is calculated for the module.

    If the manufacturer doesn't enter the specific part-load operation point and you select the "standard part load operation" option, a curve for the cell type is used (e.g. monocrystalline) for the calculation.

    To ensure that the program never simulates yields which are not achievable in reality, the standard part load operation curve tends towards a pessimistic scenario. Which part-load operation curve is used for the selected modules can be seen on the "U/I Char. -Part Load" tab under "Databases" => "PV modules".

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  • Why is the specific annual yield for amorphous modules better than for monocrystalline modules, even when the systems are the same size?

    The decisive factor for the yield is the part-load efficiency. In this respect amorphous modules usually have a better efficiency than monocrystalline modules. The part-load efficiency is presented in the efficiency characteristic curve which can be displayed under Databases > PV Module > 'U/I Char. - Part Load' by clicking the 'Efficiency Char. Curve' button.

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  • How are thin-film modules treated in PV*SOL calculations?

    All modules are calculated with the part-load characteristic curve (efficiency or 'ETA' curve). The specific part load operation for the modules is in some cases given by the manufacturer (see Databases > PV Module > 'U/I Char. - Part Load').

    In all other cases a characteristic curve is used that is specific to the cell type. It is possible to select from 12 different cell types. For the 5 thin film types: amorph, HIT, CIS, CdTe and triple a-Si, standard characteristic curves are available for typical part-load operation.

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  • Can you print the roof layout in PV*SOL?

    Yes. You can print the roof layout as a separate document via the menu 'Results' > 'Project Report' > 'Roof Layout'. This function is only active if the roof layout has been used for the project planning. In 3D, the 'Snapshot' feature allows captured images to be placed in the report.

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  • Would it be possible to guarantee that the predictions generated using PV*SOL will be matched by the actual output after installation?

    The margin of error of user input data versus experimental means there is no guarantee that modelling will synchronise exactly with on-site measurements; neither can it be expected that any given month, day, hour or minute will match that in the modelling since climate and load values are acquired as historical averages.

    Nevertheless, the margins of error can be reduced if on-site measurements are made to the nearest millimetre or tenth of a degree. Furthermore, module characteristics are best checked randomly to ascertain individual power outputs which otherwise can vary from labelling.

    Financial predictions are at risk from future variances in inflation, tax and interest rates. A default caveat is provided with the reports.

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  • Does the PV*SOL system schematic show isolators on the report to the customer?

    The default schematic can be exported into a graphic or CAD package for further customisation.

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  • How do I get results for the module temperature during operation?

    Run a simulation and choose the options in the Diagram Editor graphical results. Now select 'Module Temperature'. Right click on the area and they data can be copied to a spreadsheet.

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  • How do I create results for every half-hour of year ?

    In summary, a minute-level simulation is first saved as an Excel file. The data can then be averaged for any preferred time-resolution greater than one minute.

    If you have been on one of training courses we give you a working exmaple of how to do this.

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  • How are the terms Gross PV Surface Area and PV Solar Surface Area defined? Why are the values different in some cases?

    The PV Solar Surface Area is the area that forms the basis of the manufacturer's measurement of module efficiency. For simulation, the program determines the Solar Surface Area from the calculated power and efficiency (ETA), using the following formula:

    PV Solar Surface Area = Nominal output (STC) / (1000 W/m2 * ETA(STC))

    In some cases, the resulting figure is different from the Gross PV Surface Area. If, for example, the manufacturer does not take the module frame into account when calculating the ETA (STC), in order to obtain a better ETA (STC), the Solar Surface Area will be smaller. For a Solar Surface Area that corresponds to the Gross PV Surface Area, you should click on the calculator symbol to calculate the Module Efficiency.

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  • Where are the losses due to shading shown?

    The results differ between using 2D and 3D and dependant on the number of arrays. If there is no shading, the values of zero are reported in the Energy Balance and the Excel results under ‘Shading’ and other similar column headings. If 2D shading is present then accordingly non-zero values appear. The partial module shading and mismatch from shading is not considered in 2D. In 3D this same value is termed as ‘Module Independent’ i.e. where affecting all modules equally. The ‘Shading’ column in the Excel spreadsheet represents the module independent shading whether in 2D or 3D. Shading is also shown in the diagram editor. Non-zero values for partial and mismatch are only shown for 3D.

    In 3D, effectively two simulations are done one with and one without shading to report the ‘Yield reduction due to shading' in the Simulation results even if only shading from the far horizon. This is the total loss of yield due to the influence of shading including direct shading losses, low-light performance (lower efficiency) of the module and the MPP tracking of the inverter if the shading causes a MPP outside the MPP voltage range. Mismatch and Partial are also now itemised in 3D. Module-specific shading is also reported under the Energy System balance and Configuration.

    The shading frequency is available in 3D if near or middle distance shading objects cast a sharp shadow on the array. This is indicated as a percentage of the year during daylight that the module is shaded.

    Note: The self-shading of mounted module rows is factored in automatically only in the 3D-Visualization. Minute values for global irradiance are especially important for the realistic simulation of yield losses.

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  • How are the electricity production costs calculated? ?

    To calculate the electricity production costs:

    1. The investment costs are divided by the number of years you have entered for the assessment period.

    2. The annual cost are added to this value, if existing.

    3. Then the total costs are divided by the PV generator energy (AC grid).

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Database Questions

  • How do I import a load profile such as Half-Hourly (HH) from a Smart meter?

    The import can be done using resolutions from per minute to hourly. In 'Consumption' > 'Import Load Profile' >'Import New Load Profile'. Then press 'F1' for context help and follow those instructions exactly! (i.e. Help page: Home > Consumption > Import Load Profile). If the measured data is split into horizontal weekly or monthly rows then this must first be converted to a single column of data. One way to do this is either via Excel or a free third party program called 'Notepad ++' using the relevant Find & Replace 'switches' i.e. in extended search mode replace \t (tabs) with \n (line breaks) to convert to a single column of data. We cover this in more detail in our training courses.

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  • How can I find out whether the latest version of the module database is installed on my PC?

    Assuming the license has a current software maintenance agreement then the program will automatically check for updates and additions to the database if you select the from the menu 'Options' > 'Program Options'.

    You are also able to carry out an 'Update Check' manually via the Menu > Help > 'Check for Updates'

    Also further information is found via the Menu > Help > Info. The date and version is shown for the file PV*SOL.sdf

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  • How do I add modules, batteries or inverters I want to use to the database?

    Manufacturers can add the technical data of their products themselves to the PV*SOL online database. To do so manufacturers first send an email to database@valentin-software.com with their company contact details and then they will be provided with the login details.

    A user can also create custom modules, inverters & battery systems via the PV*SOL Main menu > Database > Module/Inverter/Battery. Using the icons at the top of the dialogue, you should then either:

    - create a copy of a similar existing product and rename/alter as required

    - or create a new entry from the icons at the top of the list.

    Only copies can be made of system files which cannot otherwise be altered except be the original manufacturer that uploaded it to the central database. Users can also a request to their equipment distributor to update so that ultimately the manufacturer uploads the correct specification for everyone to access as above. If they have a copy of PV*SOL they can email you a saved project with that module and it’d then appear in your database as well. If you have the specification sheet there is a good chance it’ll be similar to an existing item hence you might start with a database copy of that.

    To note battery systems are a combination made up of batteries & battery inverters. The latter do not have their own database but are often mentioned in the title description in the battery systems description.

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  • Where does the data for determining the CO2 savings come from? ('CO2 Emissions avoided' in the project report.)

    The database delivered with the program includes a generic value of 600 g/kWh. This should be adjusted to the applicable country via 'Climate, Grid and System Type' > 'AC Mains'

    Further information for the UK can be found here: https://www.solardesign.co.uk/pvsol_emission_factors.php

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  • How do I copy over my user-created database items and favourites when changing my program version or transferring my license?

    From 2017 many of these details are stored in each saved project. These are then automatically transfered to another computer when that project is opened. This works for all tariffs, modules, inverters, battery systems, batteries, optimizers and electric vehicles.

    Another way would be to copy the whole database file “pvsol.sdf”. It is located in the following directory 'C:\ProgramData\Valentin EnergieSoftware\PVdatabase\Version5.0'. This folder is normally hidden so if it is enable the option "Show hidden files and folders" in the Windows folder settings.

    If you have custom load profile to mport then these are stored in the “ConsumptionDb.sdf” under “C:\ProgramData\Valentin EnergieSoftware\PVdatabase\Version5.0”. If you want to transfer them you would have to copy this file.

    The self-created climate data records are stored under “C:\ProgramData\Valentin EnergieSoftware\MeteoSyn\WBV\_userfiles” in the different country folders. You have to either copy all the individual files or the entire country folder to the new computer.

    To copy of any favourites, these details are stored in the program's 'ini' file. Do not copy the whole file, just the part indicated below:

    • Close both programs
    • Using Windows Files and Folders, navigate to the following directory on the newer PC:
      • C:\Users\\Documents\Valentin EnergieSoftware\PVSOL premium 2018
    • Right-click on "pvsol premium.ini" and 'Copy' then 'Paste' a temporary back-up copy to your Desktop. Rename it if wished. If all goes well this file can be deleted later.
    • Then right-click again on the original "pvsol premium.ini" and 'Open With' a simple editor such as Notepad
    • Scroll down and select & copy (Right-click then 'Copy') everything between and including the terms "Favoritenverwaltung" which appears twice as it is marked in the screenshot below. The number of items found items will vary depending on how many favourites were previously saved.
    • pvsol copying favourites
    • Open the current pvsol premium.ini" The file can be found under: "C:\Users\\Documents\Valentin EnergieSoftware\"
    • Paste everything in the same place, overwriting everything between and including the terms "Favoritenverwaltung" which appears twice
    • Open PV*SOL premium. The favorites should now be in the new version

    Any selections in the User and Extended Program options like the company logo, units and language choices should be manually set and the logo re-imported.

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  • Why can't I find Tesla and similar products in the battery system database?

    Since the PV*SOL 2016 version, it is possilbe to design for grid-connected AC-coupled battery storage systems and the SMA brand of off-grid DC-coupled battery systems. Some grid-connected battery systems on the market (such as Tesla) use a DC-coupled battery, and so may not be currently listed in the database.

    However, it is possible to add a battery of any brand / model to a custom battery system and then add a battery inverter of your own choice (providing the technical details are known).

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  • Are there load profiles suitable for the Southern hemisphere?

    If a load profile is imported from say a smart meter that was already based in the Southern hemisphere then the seasons and months will already be synchronised. If a profile from the Northern hemisphere is found, such as those that come bundled with the program, then the months must be inverted to match the different seasons. This can be done from the results Excel spreadsheet option where the load profile can be isolated in either hourly or minute resoloution. The data can then be manually inverted so that summer becomes winter etc. then saved as a CSV format. This can then be re-imported back into PV*SOL with a new file name.

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  • Can online sources of 2D terrain profiles be imported into the 2D shading diagram?

    See:'General FAQ Horizon'

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  • How do I select 'From-grid' electrical tariffs that vary during the days or seasons?

    There are so many variants of this appearing every day that you are likely to need to create a custom one to match your customer's local supplier. First view one of the Example Projects > ‘Example TOU’(= Time-of-use). Open this and navigate the ‘Financial analysis tab > ‘Select’. This is opposite the Net Metering section. Then right click > Edit on either ‘Example Rate Net Metering’ or ‘TOU Polyphase’. Viewing these will help you understand how that dialogue works. Now you will more easily save a new tariff for your own country.

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  • How do I view the part load data for a module?

    For part load data, follow this file path: Main menu > Databases > PV Module. Then right-click > Edit

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  • Can PAN format files for modules characteristics be imported into PV*SOL?

    The PAN format is a proprietary (and binary) format from PVsyst which you cannot open in PV*SOL. However you could first import your PAN file into PVsyst and then export it to clipboard. Then you can paste the module data to an Excel sheet (separating the entries by semicolon). Using PVsyst 6.4.1, an Excel sheet can be downloaded here where you can paste your data and you'll already have the correct column description for to know which value must be entered in PVSOL:

    'PAN files for PVSOL.xlsx'

    You would then open the PV module database of PV*SOL, then choose "New module" and enter the data accordingly.

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  • What is the ‘Emissions Coefficient’ in the module database specification ?

    This parameter is a leftover from the old programs PV*SOL Pro and PV*SOL Expert. It was used for the thermal balance equation in the dynamic temperature model. But this temperature model is not used anymore in the current versions. The manufacturers can also not enter the value anymore in the online database. Nevertheless the parameter is still in the database because of the old modules which we not delete. If new modules are enter then the value is set to an default value. i.e. 85 %.

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Definition of Terms

  • Where can I find definitions of common terms used in the PV*SOL report?

    Go to the Help menu > Glossary.

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  • What is the 'energy from grid'?

    The energy from grid consists of the property's electricity requirement which is met by the grid (if connected), plus the PV system's own requirement for inverter stand-by and night use.

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Economic Questions

  • Why can I not see the choice for Surplus or Net metering concepts instead of only full feed-in? And why does the From-grid tariffs or Bankability sometimes not appear in the Financial Analysis ?

    These options are affected by the previous choice of ‘System Type’ in the dialogue ‘System Type, Climate and Grid’.

    For grid-connect systems if there are no Appliances enabled then the financial choice is only Full-Feed in with Bankability.

    If Appliances are enabled then first the annual load must be entered there and then you will see there is a choice of finance of Surplus or Net metering. Plus the from-grid tariffs are now considered.

    All tariffs can be defined at any time through the main Menu ‘Databases’.

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  • How do I use the current UK FiTs in PV*SOL?

    These are available in the Tariffs selection of the Financial Analysis. Both the Export and Generation tariffs are separately applied. Options to use 50% deeming are also available.

    If the latest ones are not shown then you can easily add your own based on the a previous one. In the databse view, right-click and copy an exisitng tariff. Rename to suit the new period and change the 'valid from' date. Then adjust the tariff rates that are different by comparing to the official announmcents from OFGEM. Then click 'OK' and the new tariff will appear in your list. Repeat this for the different building classifications and export tariiff as required.

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  • I have to load my preferred feed-in tariff each time I set up a new project. Is it possible to save the tariff settings to be used for new projects centrally?

    The best way to use PV*SOL is to create some templates on which to base future projects and in this way many options do not have to be repeatedly entered. There are also frequent choices in the program to save favourite climate, module, inverters and other dialogues 'Save as Default'.

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  • Does PV*SOL know the capital cost or exchange rates of any items?

    In short, no. However in the Financial Analysis, it is possible to use normalised costs/kW, and these can be stored as template projects. The 'Detailed' view on these allows individual items to be summed.

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  • In the results, why does the Feed-in/Export tariff cash flow rate change every year?

    These values are affected by the module degradation, inflation of the tariffs and annual average return on capital (otherwise employed). The latter can be considered the opportunity-loss of interest-bearing capital that would otherwise be gained if the PV project had not proceeded.

    For cashflow tables, degradation and inflation rates are applied on a monthly basis over the entire assessment period. This is applied from the start of the first year. If the start of operation is a part-year then the first year will not match subsequent years. Whereas in the results, 'Total payment from utility in 1st year' is shown as if a complete year.

    This value is affected by module degradation, opportunity-loss of interest-bearing capital and inflation of tariffs.

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  • I am involved with a Power Purchasing Agreement - how is this represented in PV*SOL?

    More complex arrangements are best created in a separate spreadsheet after copy/pasting the cash-flow table in the results.

    However, there is the option within the program to use 'Price of Electricity sold to Third Party' in the Financial Analysis dialogue [currency/kWh]. This is used to calculate the income from the electricity that is not compensated by the power company but is sold directly to third parties at market prices.

    If entered, this rate is multiplied with the grid feed-in (export energy to grid). If a feed-in tariff is selected, then then this is first used for the calculation of the income. Only if the feed-in tariff is not used or has expired then the third party tariff is used. The third party tariff is also used if you have defined that you are not paid for the full amount of the feed-in energy such as when the feed-in tariff contains an un-compensated portion of the electricity.

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  • What effect does the starting date have on the economic calculation?

    The starting date is adjusted in the initial project date tab. The default is the date of first creating the project. If there is a mismatch of this date and any defined tariffs such as Feed-In tariffs then a non-critical advisory message appears at the bottom of the screen and so you may wish to adjust the starting date or adjust the choice of tariffs before completing the project.

    If you chose the 1st of January the first year’s economic calculation will then run from the January 1st to December 31st. For any other staring date in the year the first year’s economic period is from the starting date to the end of the month before the starting month e.g. If the starting date is set to 31 December it goes from December 31st to November 30th. All other years are counted as complete 365 days.

    If the starting date is other than the first of the month, the shortfall of the ‘lost’ days in the first year is calculated from the mean daily feed-in rate (energy export to grid) multiplied by the number of ‘lost’ days multiplied by the chosen feed-in or third party rate.

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