How do you plan a PV system in PlanElec?

In PlanElec you plan a PV system in the studio's Energy mode: you lay out module arrays on the roof surfaces in the 3D view, add an inverter in the PV system panel and assign the modules as strings to its MPPT inputs. You need a floor plan with a roof and an installation with at least one protective device the inverter can connect to. The result is a documented PV generator in the single-line diagram, one string symbol per string on the situation plan, a PVGIS-based yield forecast and a PV planning register in the self-check report. The string check compares the module and inverter data you document; structural design, shading by surrounding objects and testing of the installed system stay outside PlanElec. The official conformity inspection in Belgium (AREI in Dutch and German, RGIE in French) is carried out by an approved inspection body.

Which steps make up a PV design?

The order is a suggestion. You can also create the inverter in the single-line diagram first and lay out the roof later.

How do you lay out module arrays on the roof?

1. Open Energy mode in the studio. The 3D view shows the whole building including its roof. PlanElec derives the roof surfaces from the floor plan; in the roof bar you choose the Roof shape and pitch.
2. In the PV modules bar, pick a placement tool: Single module (one click), Row (drag a line), Array (drag a rectangle) or Entire roof surface (click a roof surface to fill it completely). With the Best layout toggle, a click on the surface opens the best format variants.
3. Set the defaults for new arrays first: portrait or landscape and, on flat roofs, Flat roof mounting (Flat (0°), South-facing racks or East-west) with Tilt (°). On pitched roofs the modules lie parallel to the roof.
4. Click an array with Select. In the array menu, choose the Module type from the catalogue; its power and dimensions feed into string design and the yield forecast. Dragging moves the array, the handles resize it on the module grid and Delete removes it.

Success check: the bar shows the total module count and installed power in kWp. Every array operation is a single undo step. In the yield forecast, arrays without a module type are calculated with a standard module; assumed dimensions are flagged there.

How do you create the inverter, MPPTs and strings?

1. In Energy mode, open the PV system panel and click Add inverter.
2. In the dialog, search under Verified catalog or in the Synergrid list (all homologated inverters) and take over the device with Add to project. If your model is not listed, choose Create without catalogue. Missing manufacturer values stay empty and are never invented; add voltage limits under Device data and current limits per MPPT under Edit limits.
3. PlanElec connects the inverter to a dedicated PV circuit. An existing circuit breaker already used for a generator is reused. Otherwise a new MCB PV inverter (default C 25 A, 2-pole) is created under the first residual current device. Adjust its rating to your inverter's rated AC current. If there is no protective device at all, PlanElec tells you to create a distribution board with a circuit breaker first.
4. In an MPPT section, click Assign modules, or Assign strings in the PV modules bar. A banner shows the MPPT, the allowed string length and the keys.
5. Click the modules in chain order. The array chip adds all free modules of an array in serpentine order. Enter creates the string, Shift+Enter creates a parallel string on the same MPPT, Esc discards the draft and Backspace removes the last module.

Alternatively, Distribute automatically assigns all free modules in one step. The summary lists the strings created per array and MPPT and the reasons any modules were left over, for example a module current that is too high for an MPPT.

You can deliberately create a blocked string with Create anyway (Ctrl/⌘+Enter); the finding remains. If the draft is too long, the banner proposes an even split across several strings. For microinverters and optimisers the check reports "not applicable", because the manufacturer's rules apply there.

The Conflicts section counts modules without a string, missing module references, strings spanning several roof surfaces and strings mixing module types. PlanElec does not silently repair these conflicts: you adjust the string deliberately or redistribute.

How does a string appear on the situation plan?

On the situation plan, a module symbol stands for one complete string, not a single module. Every string of an inverter needs exactly one such symbol.

1. Switch to Electrical mode and choose Solar panel / PV module from the device palette under Generation. Place it where the array sits on the plan.
2. Select the symbol. In its toolbar, open Select PV string and pick the entry "inverter · string".
3. Repeat for each string. If no strings exist yet, the toolbar asks you to add an inverter with PV strings first.

The symbol then carries a label with the string, module count, module power and kWp. The self-check reports every mismatch:

What does the PV side of the single-line diagram show?

Select the inverter in the Single-line diagram. You can also create an inverter there via the palette group Generation → PV inverter. The inspector groups the PV data in five sections:

From this the diagram shows single and parallel strings per MPPT, the Y branch or combiner, protective devices with their status, the AC isolation point, the documented cable segments and the separate frame PE down to the earthing connection. Strings without an MPPT appear under "Unassigned DC strings (open)". Missing manufacturer limits stay visible and are not filled in.

For the frame PE, AREI 7.112.2 requires earthing of the modules' metal frames and their structures, unless the manufacturer prohibits it, with a protective conductor at least as large as the AC protective conductor and no smaller than 2.5 mm² with mechanical protection or 4 mm² without. The self-check compares your cross-section with that minimum. If you select "Prohibited by manufacturer", it expects a reference as evidence.

Deriving DC lengths: in the 3D view, place a Roof penetration anchor on the roof and assign it in the string row under Penetration. PlanElec then derives three segments: across the roof to the penetration, vertically through the ceiling and through the building to the inverter. A typed length takes priority; Restore derived value returns to the geometry. If a segment is missing, the total length stays unknown rather than zero. The building segment is a direct connection; a custom route cannot be drawn for it yet.

How do you calculate the yield forecast?

1. In the PV system panel, expand the PV yield forecast and open the Inputs tab.
2. Choose Set site. PlanElec takes the installation address from the project metadata and searches Belgian addresses. Check the map and north direction, tick Confirm site and north direction and click Confirm site. Without this confirmation the forecast does not run.
3. Review the Assumptions: System losses (%) (14 % by default), module technology, mounting, horizon (PVGIS terrain model or none) and radiation database.
4. Click Calculate. The Result tab shows annual yield, power, specific yield in kWh/kWp and the monthly chart.

The calculation uses PVGIS 5.3 from the EU Joint Research Centre, per orientation group. Only coordinates and physical parameters are sent, never project or customer names.

The loss chain needs an inverter with strings. Without rated AC power it calculates without clipping at a constant efficiency. Without a verified efficiency, the flagged 96 % assumption applies. The DC cable loss uses the length, the cross-section from the inspector and the module voltage; if anything is missing, the string uses 2 % and states why. If a battery is documented on the inverter, the clipping figure is an upper bound.

In the Variants tab you compare other modules with Same layout or Same area; variants change neither the design nor the strings. When you change geometry, site, assumptions or strings, the result is marked Result is stale and the report stays locked until you recalculate. Open report creates the PV yield report from the frozen state; it is also available under Export.

Limits: P50 and P90 describe past weather years, not a yield guarantee. Shading by objects in the scene is not taken into account and there is no financial calculation. A failed orientation group stays visible as a partial result, never as zero yield.

Can you estimate self-consumption, battery storage and an EV?

Yes, as a pilot feature inside the yield forecast. In the Inputs tab, enter the annual consumption under Electricity consumption and choose a profile; under Electric vehicle you can add one or two vehicles. In the Result tab, Calculate self-consumption runs a quarter-hourly calculation for a typical year: self-consumption rate, self-sufficiency, grid import and feed-in per month. The Battery storage section compares the situation without and with the project battery and ranks capacities in the Size comparison; the proposal is based on an assumed threshold.

The profiles are averaged Flemish households (Fluvius, 2024), not your meter; Wallonia and Brussels are assumed to follow the same curve. Peaks are smoothed, so the benefit of a battery may be overestimated. There are no tariffs, no savings or payback calculation, and these figures appear neither in the yield report nor in the dossier.

What does the self-check report say about PV?

As soon as the project contains an inverter, the AREI/RGIE self-check report adds the section PV installation data for inspection. It is explicitly labelled as a project planning register and is not a report issued by an approved inspection body. For each inverter it lists:

• name, manufacturer and model,
• serial number and maximum AC power,
• PV generator with module count, kWp, number of MPPTs and strings.

This gives you the data that AREI 7.112.4 requires in the conformity inspection report for a domestic PV installation. Values you have not entered appear as "Not provided". The report also shows the findings of the PV rules, for example on frame PE under AREI 7.112.2 and on string design. Which rules PlanElec evaluates is listed in What the self-check verifies. If the self-check is switched off for the project, the report is not available.

What does the material list take from the PV design?

The material list is a pilot feature under Export. From the PV DC side it only takes structured data: modules with type and count, protective devices explicitly documented as present, and known cable segments. Positive and negative conductors together count twice the route length; an accompanying PE/PA conductor counts once. Integrated protective devices and an AC isolation point provided by the source protective device are not counted twice.

The PV system bill of materials in the material overview adds mounting items with the status Documented, Assumption, Open or Sized externally. Open items show a gap instead of zero. The DC count does not add frame PE, connectors, reserves or offcuts. The list is manufacturer-neutral, has no prices and is not an order list; structural design and fixings are sized with the manufacturer's configurator or by a structural engineer. See also Export documents.

What does PlanElec not cover for PV?

You plan the inverter circuit like any other circuit: see Plan installation and distribution boards. How to place and connect symbols on the situation plan is explained in Place and connect electrical symbols.