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PV*SOL Frequently Asked Questions

Setup and Error Messages

Building and site modelling

Configuration

Results

Database Questions

Economic Questions

Setup and Error Messages

Building and site modelling

Configuration

Results

  • Where are the results for mains voltage, 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.

    If you plan a grid connected system then for grid-connect systems adjusting the mains voltage value has no effect other than display on the circuit diagram. For off-grid systems the program checks if the battery inverters nominal voltage matches the internal 'grid' voltage. Depending on that you can use a battery inverter or not.

    For power-clipping/down-regulation 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 is 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?

    In 3D projects you can export/print the roof layout via the options in 'Project Report' - Overview or Dimensioning Plan. In 2D the graphic roof layout will be the choice. In 3D, the 'Snapshot' feature also 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?

    From versions 2019 onwards, the cabling schematic can be customised with user defined items. In any case 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 which is then converted inside Excel. 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 example 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 dependent 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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  • What is the definition of the performance ratio (PR) ?

    In PV*SOL the Performance Ratio is calculated as follows:

    Performance Ratio = (PV Generator Power + Stand-by Consumption) / ([{Global Radiation at the module - Reflection on the Module Interface} x Size of the PV field] * [Module efficiency / 100])

    •PV Generator Power (= Grid-Feed-In with full feed-in)

    •Stand-by Consumption

    •Global Radiation at the module

    •Reflection on the Module Interface

    •Size of the PV field

    •Module efficiency

    The above values can be found in the energy balance. The mathematical sign of the values have to be considered, if you use them in the above formula.

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  • How is the peak consumption power calculated and how can it be changed ?

    Peak power consumption is displayed in the consumption dialogue and used to assist with the choice of battery inverters with Battery System.

    Consumption charts and exportable tables down to one minute resolution can be found on the Results Page > Diagram Editor. The hourly plots are also shown in the Consumption dialogue > Time Series.

    For individual appliances see this FAQ: https://help.valentin-software.com/pvsol/en/calculation/consumption/

    Dependant on the format of the consumption will alter how the peak power is calculated. The choice of one hour or one minute resolution will also affect how this value appears in the exported tables. Note that if the overall calculation is set to one hour resolution, then the consumption is assumed to be constant across each hour. In this case, an individual appliance originally created with an operating time of 15 minutes per hour would be simulated as a device that runs for 1 hour with a quarter of the load. If subsequently the general calculation resolution is changed to minute resolution there would be 15 values shown of the same power per minute for 15 minutes and so the peak power would be displayed the same.

    Load profiles from daily profiles are created as hourly. A higher peak value can be created if all the daily consumption is set to occur in one hour @ 100%. The lowest peak occurs if spread equally over 24 hours @ 4.16%. Alternatively simply add a short-term use appliance to a base profile that operates for example 1 hour on one day at midday in summer.

    For load profiles from measured values the highest power found will be reported regardless of resolution. However if original consumption values were imported at resolutions less than one hour and subsequently the general calculating resolution is set at one hour then the values are averaged in each hour. The peak power is still reported correctly as above but if the final consumption values are exported in hourly mode then the peak values will appear less as they would have been averaged.

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  • How can I change the images used in the presentation report?

    The image on the front of the report is independent of any other shown inside via the Project data scree. This is controlled in the Project Data section were you can add any extra images.

    You can chose your own photos from any 3D viewpoint using the camera snapshot icon inside 3D. Once taken in the Screenshot Manager, right-click your preferred image and allocate as the Overview image. If using 3D, the overview photo can also be switched off via the program options and saved as a presentation template.

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  • How can the results chart 'Cumulative Total Energy Generation' show just the AC inverter generation ?

    The graph normally shows the balance between generated PV energy (yellow) and the demand (grey). To display just the cumulative generation on this chart, temporarily adjust the consumption to the smallest amount = 1 kWh. The chart can then be manually copied and appended to the report in Word if required.

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Database Questions

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

    From 2020 the consumption dialogue allows HH import to be selected. The import can be done using various resolutions from per minute to hourly. For detailed instructions see 'Consumption' > 'Import Load Profile' >'Import New Load Profile'. Then press 'F1' for context help.

    In the case of importing leap years the calendar must be used to for one of the leap years. If the year the data is less than a year then the start date and number of complete data days are chosen. The extra or missing days will not be shown in the results as these will instead be interpolated. In the results only complete year @365 days are shown.

    We recommend first using Excel to analyses data before import in case of accidental missing days. With persistent file import problems also inspect the file with a plain text reader such Windows Notepad. If duplicate commas are discovered then try cut/paste on the affected column or use a Find/Replace feature found in a 3rd party app Notepad++.

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

    Assuming the licence has a current software maintenance agreement then the program will automatically check for updates and additions to the database if you select from the menu 'Options' > 'Program Options'. From 2020 the databases are stored online.

    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. Also see further at this link: https://pvsol-database.valentin-software.com/

    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.

    From the 2020 versions user customised databases are stored online and can be easily shared with other users. See Main Menu > Options > Database Options

    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 carbon dioxide (CO2) savings come from? ('CO2 Emissions avoided' in the project report.)

    The database delivered with the program includes a generic value of 470 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 to adjust the CO2 grid rate over time ?

    To account for module degradation over time, use the 'PV Energy during Observation period' chart in the results. Right-click and copy table to clipboard. Then paste in a spreadsheet to total the energy of the period of years set in the Financial section. Within the spreadsheet a diminishing CO2 rate can then be applied to each year and then totalled.

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

    From 2020 an online database is used which can accessed from any licence holder or computer providing the user ID are remembered. These can be found in the program options.

    Prior to this to 2017 many of details are stored in each saved project. These are then automatically transferred 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 enable the option "Show hidden files and folders" in the Windows folder settings.

    If you have custom load profile to import 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 favourites 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 some brands of battery systems in the battery system database?

    The brand name used in the listings can vary between the battery or inverter manufacturer. It is possible to design for grid-connected AC-coupled, DC-coupled or hybrid (DC-intermediate) battery storage systems as well as off-grid. Some grid-connected battery systems on the market.

    It is possible to add a battery of any brand / model to a user-created custom battery system and then add a name of your own choice assuming the technical details are known.

    Note if a hybrid battery system is used, the same type of module inverter should be selected.

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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 resolution. 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. Alternatively when creating a measured-value profile there is a simple option 'Shift load profile by half a year'.

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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?

    Yes from 2022 a direct import is possible. The PAN format is a proprietary (and binary) format from PVsyst which you cannot directly open in PV*SOL.

    An Excel template can assit manual PAN format export: '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 entered 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 including the SEGs 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 a previous one. In the database view, right-click and copy an existing 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 announcements from OFGEM. Then click 'OK' and the new tariff will appear in your list. Repeat this for the different building classifications and export tariff 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 allow 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 and differ from the utility payment ?

    These values are affected by the module degradation, inflation of the feed-in tariffs (or third party resale) 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.

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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 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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