Short answer
What you need to know first.
A large PV system in Aargau should first be planned as a building and grid project, not as a mere module area. The standard case starts with a roof survey, structural and electrical pre-check, clarification of the notification or permitting route and a grid-connection request to the responsible distribution grid operator. In parallel, the project must decide whether self-consumption, ZEV/vZEV, site supply or feed-in is the priority. Incentive and tax questions belong in the project file, but they do not replace a property-specific economic calculation.
Important
This page is general guidance for large PV systems in Canton Aargau. It does not replace property-specific technical planning, a grid-connection approval, permitting review, tax or incentive advice, or an assessment of structure, fire safety or roof waterproofing. The current documents of canton, municipality, grid operator, Pronovo and the responsible specialist bodies are binding.
Decision points
What determines the right path.
The usable roof area is not the same as the visible roof area. Edge distances, roof structures, maintenance routes, fall protection, shading, roof membrane and permissible additional load limit the layout. Especially on flat roofs, the combination of ballast, wind uplift, snow load and waterproofing decides whether the system can operate long-term without damage.
Aargau’s focus is clearly on existing roof and facade areas. The cantonal solar offensive identifies large PV potential for Aargau and includes initial measures in areas such as information, advice, the canton’s role model function and support for large systems. Private owners cannot derive an automatic funding promise from this; current eligibility must be checked project-specifically with the official bodies.
For large systems, grid connection is a planning path of its own. Inverter capacity, export capacity, metering concept, meter space, grid reinforcement, feed-in model and commissioning must be clarified with the responsible distribution grid operator. Starting this coordination too late risks schedule shifts or a system size that must be changed economically or technically.
The economic logic depends on the consumption model. A commercial operation with daytime load can reach a different self-consumption share than a warehouse, apartment building or agricultural property. Before quoting, the project therefore needs to clarify whether direct consumption, battery storage, ZEV/vZEV, load management or mainly feed-in determines the project value.
Permitting and design remain relevant even on large roofs. In Aargau, roof-mounted solar systems that comply with design requirements are generally subject to notification; if these requirements do not fit or protection interests are affected, a building permit may be required. For large commercial or agricultural roofs, this route should be clarified with the municipality and specialist planning before material is ordered.
Sequence
How the project stays cleanly managed.
- 1
Define the project objectiveclarify whether the system should primarily serve self-consumption, tenant electricity, site supply, charging infrastructure, heat pump, process electricity or feed-in. This objective determines system size, inverters, metering concept and later billing.
- 2
Survey the roof and buildingroof condition, waterproofing, load-bearing capacity, structures, shading, maintenance routes, fire-safety requirements and fall protection are checked on site. If roof renovation is foreseeable, it belongs before or together with PV planning in the schedule.
- 3
Start authority and grid paths in parallelclassify the notification or permitting route with municipality and canton, while clarifying grid connection, export capacity, metering scheme and meter location with the responsible distribution grid operator. Both paths influence layout and schedule.
- 4
Check incentive logicPronovo category, possible cantonal large-system programmes, municipal contributions and tax treatment are compared with current official documents. Incentive amounts should only enter the economic calculation once project size and eligibility are robust.
- 5
Make quotes comparablerequire separate items for mounting structure, roof protection, scaffolding, electrical work, grid-operator coordination, monitoring, documentation and commissioning. On large roofs, these interfaces are often more important than the module price alone.
Checklist
Questions to settle before the quote.
- Survey roof area, load-bearing capacity, roof membrane and fall protection before module planning
- Compare self-consumption, tenant power model or full feed-in economically at an early stage
- Do not check notification procedure, protection constraints, grid connection and Pronovo category only after the quote
- Confirm cantonal large-system logic and current incentive programmes only through official bodies
FAQ
Common questions on this topic.
Sources
Official sources & references.
The responsible authorities are decisive. Always verify binding details – amounts, deadlines and conditions – for your specific property against the current status of the respective authority.