Ab wann gilt eine Photovoltaikanlage als Großanlage?

Eine gesetzliche Definition gibt es nicht. In der Praxis werden Anlagen ab etwa 100 kWp häufig als Großanlagen eingeordnet, weil ab dieser Größenordnung zusätzliche Anforderungen an Vermarktung, Messkonzepte und Fernsteuerbarkeit relevant werden. Ab einer Leistung im Megawattbereich kommen weitere Anforderungen bei Netzanschluss, Vermarktung und gegebenenfalls der Förderstruktur hinzu.

Wie viel Fläche braucht eine PV-Großanlage?

Als Anhaltswert benötigt ein Megawatt Peak auf einem Flachdach rund 8.000 bis 10.000 Quadratmeter, auf einer Freifläche etwa 1 bis 1,5 Hektar. Der genaue Wert hängt von Modulleistung, Aufständerung und Reihenabstand ab.

Lohnt sich eine Großanlage ohne Batteriespeicher?

Ja, wenn der Standort einen hohen gleichzeitigen Verbrauch hat. Bei ausgeprägten Lastspitzen oder geringem Tagesverbrauch kann ein Speicher die Wirtschaftlichkeit verbessern.

Was passiert mit dem Strom, den wir nicht selbst verbrauchen?

Überschüssiger Strom kann über einen Direktvermarkter an den Strommarkt verkauft oder im Rahmen eines langfristigen Stromliefervertrags (PPA) vermarktet werden. Bei größeren Photovoltaikanlagen gelten zudem zusätzliche Anforderungen an Vermarktung, Messung und Fernsteuerbarkeit. Für Anlagen mit mehr als 100 kW installierter Leistung ist die Direktvermarktung grundsätzlich der Regelfall.

Wie lange dauert die Umsetzung?

Bei Dachanlagen mehrere Monate, bei Freiflächenanlagen mit Bebauungsplanverfahren ein bis zwei Jahre. Der Netzanschluss bestimmt den Zeitplan häufig stärker als die Bauzeit.

Muss unser Dach vorher saniert werden?

Nur wenn Statik oder Abdichtung es erfordern. Da eine PV-Anlage über zwanzig Jahre auf dem Dach bleibt, ist eine anstehende Sanierung im selben Zug meist wirtschaftlicher als eine spätere Demontage.

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Large-scale PV systems:
when a solar installation counts as large and what that changes for your company

The term “large-scale PV system” is remarkably vague. Some providers use it for installations from 30 kWp upwards. Others mean projects in the double-digit megawatt range. For companies considering their own solar installation, that is not much help. What matters is not the label but the question of the capacity at which a project genuinely starts to behave differently. That affects how the electricity is marketed, the grid connection, the permits and the effort required to operate the system.

Large-scale solar installation on an industrial roof

Contents of this article

When does a solar installation count as large-scale?Roof, open space or car park What makes a large-scale system pay off The path to a large-scale PV system Common pitfalls Large-scale systems in practice Frequently asked questions

Classification

When does a solar installation count as large-scale?

There is no legal definition. What does exist are capacity thresholds at which the requirements for an installation change abruptly. Those thresholds are the real answer to the question.

In practice this means that an 80 kWp installation on an office roof and a 3 MWp installation on a logistics hall are two entirely different types of project – technically, contractually and in terms of schedule. The transition does not happen at a particular number of modules, but where the grid connection and the marketing of the electricity become projects in their own right.

From around 100 kilowatts

From a system size of around 100 kWp, direct marketing becomes considerably more important in practice. Depending on system size and the applicable legal framework, additional requirements for metering, remote control and marketing may apply. This is where what can sensibly be called a large-scale system begins.

Mid three-digit kW range

As capacity increases, the grid connection is often made at medium voltage. Whether that is necessary depends on the grid operator’s requirements and the grid capacity available on site.

From one megawatt

The funding logic changes again. For large installations, EEG auctions can play an important role. Which support mechanisms are available depends on the size and type of installation and on the legal framework in force at the time.

Surfaces

Roof, open space or car park: three routes to the same capacity

Solar installation on the flat roof of a commercial building

Rooftop systems

Rooftop systems use a surface that is there anyway. That usually makes them the most economical option, because no land has to be bought and in most cases no building permit is required. The decisive factor, however, is the structural load capacity. Existing roofs were rarely built with additional loads in mind. A structural assessment therefore comes at the start of every rooftop project, not at the end.

Ground-mounted systems

Ground-mounted systems are barely limited in area and can be oriented optimally. In return they need a site with suitable planning status, a development plan procedure and a sufficiently powerful grid connection point within reach. The lead time is considerably longer, but the economies of scale are greater.

Ground-mounted solar installation with long rows of modules

Solar carport over parking spaces at a company car park

Solar carports

Solar carports are the special case in between: they open up sealed surfaces that would otherwise go unused and combine power generation with weather protection and charging infrastructure. At sites with large staff or customer car parks they complement a rooftop system rather than competing with it.

In larger projects, several types of surface are often combined. What matters is not which design is cheapest, but which combination achieves the highest self-consumption at the site.

Economics

What makes a large-scale system pay off

With small installations, the feed-in tariff determines the return. With large-scale systems it is usually the smallest lever. Four factors count for more.

Self-consumption

Every kilowatt hour used on site is measured against the purchase price, not against the feed-in tariff. The gap between those two figures is the real driver of returns. That is why we size a large-scale system around the site’s load profile rather than around the maximum possible roof coverage.

Peak shaving

In energy-intensive operations, grid fees are driven by the annual peak load. Combined with an intelligently sized battery storage system, a PV installation can reduce those peaks and lower grid fees as a result.

Direct marketing

Surplus electricity is sold on the exchange through a direct marketer. For larger installations in particular, direct marketing plays an important role in putting the electricity generated to economic use. With the right marketing strategy it becomes a source of revenue rather than an obligation.

Operations management

Over twenty years, availability determines total yield. A fault that goes unnoticed for three weeks costs more than a full year of maintenance. Monitoring therefore belongs in the business case.

Process

The path to a large-scale PV system

Site and grid analysis

Yields, load profile, available surfaces and above all the question of what feed-in capacity the grid operator permits at the site. That enquiry should be made early. It determines the maximum system size and is often the longest item in the schedule.

Structural assessment and permits

For rooftop systems the structural assessment, for ground-mounted systems the planning status. Both are prerequisites for detailed planning and cannot be negotiated in parallel.

Technical design

Module and inverter concept, wiring, transfer station, storage sizing and the connection to an energy management system.

Marketing concept

The split between self-consumption, direct marketing and, where applicable, supply to third parties at the same site.

Construction and commissioning

Installation, grid connection, certification and registration in the market master data register.

Operation

Monitoring, maintenance, yield checks and fault clearance throughout the entire operating life.

Realistically, several months pass between the first assessment and commissioning for a rooftop system, and rather one to two years for a ground-mounted system with a development plan procedure. Planning for that lead time avoids the usual friction at the grid connection.

Practice

Common pitfalls

The grid connection is checked too late.

The system size is planned before it is clear what the grid can take. The result: replanning mid-project.

The roof structure will not take the load.

This applies to older halls in particular. A roof refurbishment combined with the PV installation is often cheaper than two separate construction projects.

The system is oversized.

Maximum coverage without regard to the load profile leads to high feed-in shares and a poorer payback.

Operations are not organised.

After commissioning, no one is responsible for monitoring and maintenance. Yield losses then only show up in the annual statement.

Projects

Large-scale systems in practice

Rooftop PV system with battery storage at a logistics centre in Dorsten

Dorsten, Nordrhein-Westfalen

Rooftop PV system & battery storage Dorsten

3.5 MWp

2023

View project

Emstek, Niedersachsen

Rooftop PV system Emstek

1 MWp

2025

View project

Aldenhoven, Nordrhein-Westfalen

Ground-mounted PV system Aldenhoven

20 MWp

2025

View project

FAQ

Frequently asked questions about large-scale PV systems

The key answers on capacity thresholds, land requirements, electricity marketing and project duration, in brief.

When does a solar installation count as large-scale?

There is no legal definition. In practice, installations from around 100 kWp upwards are often classed as large-scale, because at that order of magnitude additional requirements for marketing, metering concepts and remote control become relevant. From the megawatt range upwards, further requirements apply to grid connection, marketing and, where applicable, the support structure.

How much space does a large-scale PV system need?

As a rule of thumb, one megawatt peak needs around 8,000 to 10,000 square metres on a flat roof, or roughly 1 to 1.5 hectares on open land. The exact figure depends on module output, mounting system and row spacing.

Is a large-scale system worthwhile without battery storage?

Yes, if the site has high simultaneous consumption. Where load peaks are pronounced or daytime consumption is low, storage can improve the economics.

What happens to the electricity we do not use ourselves?

Surplus electricity can be sold to the market through a direct marketer or marketed under a long-term power purchase agreement (PPA). Larger installations are also subject to additional requirements for marketing, metering and remote control. For systems above 100 kW of installed capacity, direct marketing is generally the norm.

How long does implementation take?

Several months for rooftop systems, one to two years for ground-mounted systems requiring a development plan procedure. The grid connection often drives the schedule more than the construction work does.

Does our roof need refurbishing first?

Only if the structure or the waterproofing requires it. Since a PV system stays on the roof for twenty years, carrying out a due refurbishment at the same time is usually more economical than dismantling later.

Contact

We plan, build and operate large-scale systems

From site analysis and grid connection through to operations management – in Germany and in six other European countries. Because planning, delivery and operation are all in one pair of hands, there are no gaps in responsibility at the critical interfaces.

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Large-scale PV systems: when a solar installation counts as large and what that changes for your company

When does a solar installation count as large-scale?

Roof, open space or car park: three routes to the same capacity

Rooftop systems

Ground-mounted systems

Solar carports

What makes a large-scale system pay off

Self-consumption

Peak shaving

Direct marketing

Operations management

The path to a large-scale PV system

Site and grid analysis

Structural assessment and permits

Technical design

Marketing concept

Construction and commissioning

Operation

Common pitfalls

Large-scale systems in practice

Rooftop PV system & battery storage Dorsten

Rooftop PV system Emstek

Ground-mounted PV system Aldenhoven

Frequently asked questions about large-scale PV systems

We plan, build and operate large-scale systems

Large-scale PV systems:
when a solar installation counts as large and what that changes for your company