Electricity costs are one of the most significant expense factors for businesses. At the same time, societal and regulatory pressure to operate sustainably is increasing. A solar system on a company roof can address both challenges simultaneously -- but does the investment really make sense for every business? In this article, you will learn under what conditions photovoltaics is economically viable for commercial operations, what tax advantages you can take advantage of, and what a realistic example calculation looks like.
Whether you run a trade business, a manufacturing company, or a logistics firm: the conditions for commercial solar systems have rarely been as favourable as they are today. With our PV Energy Planner you can simulate in advance how much potential your site offers.
Advantages of a Solar System for Businesses
Permanently Reducing Electricity Costs
The most obvious advantage of a commercial PV system is the direct reduction of electricity costs. Commercial electricity prices currently stand at 20 to 35 cents per kilowatt-hour -- depending on consumption, contract, and grid fees. Self-generated solar power, by contrast, costs between 5 and 10 cents per kilowatt-hour, calculated over the entire lifetime of the system. These so-called levelised costs of electricity make photovoltaics one of the most economical energy sources available to a commercial business.
The higher the self-consumption share, the greater the savings. Businesses that primarily consume electricity during the day benefit particularly strongly, since the generation peaks of the PV system coincide with consumption.
Sustainability and Corporate Image
Sustainability has long since ceased to be a purely marketing topic. More and more business partners, clients, and end customers pay attention to the carbon footprint of their suppliers. A solar system on a company roof is a visible sign of responsible business conduct. In addition, commercial PV systems help to meet the requirements of the EU Taxonomy and the Corporate Sustainability Reporting Directive (CSRD).
For companies that participate in public tenders, demonstrably climate-friendly energy supply can become a decisive competitive advantage.
Independence from Energy Markets
The energy price crisis of recent years has shown how vulnerable companies are when they are entirely dependent on external electricity supply. With your own PV system, you significantly reduce your dependence on market price fluctuations. Supplemented by a battery storage system, the self-consumption share can be increased to 60 to 80 percent -- and with it, planning certainty for energy costs.
Which Businesses Benefit Most?
In principle, a solar system is suitable for almost any commercial business. However, the investment is particularly attractive under certain conditions:
- High daytime electricity consumption: Businesses with production equipment, cold stores, or server rooms that require a lot of electricity during the day achieve high self-consumption rates.
- Large roof areas: Warehouses, production facilities, and supermarkets often offer several thousand square metres of roof space that is ideally suited for PV systems.
- South-facing or low-pitched roofs: Flat roofs allow the modules to be optimally aligned using a mounting frame; south-facing roofs inherently deliver high yields.
- Predictable load profiles: Companies whose electricity consumption is well foreseeable can size the system optimally.
- Electric mobility in the vehicle fleet: Businesses that are transitioning their fleet to electric vehicles can use the PV system simultaneously as low-cost charging infrastructure.
Industries such as food retail, manufacturing, logistics, agriculture, and office buildings with high air-conditioning loads are typical candidates for particularly economical PV projects. On our commercial page you will find further information on industry-specific solutions.
Sizing a Commercial PV System
Getting the system size right is crucial for economic viability. A system that is too small wastes potential; a system that is too large produces surplus electricity that must be fed into the grid at low feed-in tariffs.
The Key Planning Parameters
Analyse annual electricity consumption: The first step is a thorough analysis of your load profile. Ideally, quarter-hourly meter readings from the grid operator are available, covering consumption over an entire year.
Define the self-consumption share: For commercial systems, the economically optimal self-consumption share is generally 50 to 70 percent. Higher shares can be achieved with storage, but are not always economically sensible.
Check the roof area and structural load capacity: Not every roof can bear the additional weight of PV modules (approx. 12–15 kg/m²). For older buildings, a structural assessment is essential.
Typical system sizes in the commercial sector:
| Business type | Typical system size | Estimated investment |
|---|---|---|
| Small trade business | 30–50 kWp | 30,000–50,000 EUR |
| Mid-sized manufacturing | 100–250 kWp | 90,000–225,000 EUR |
| Large warehouse / logistics | 250–750 kWp | 200,000–600,000 EUR |
| Industrial operation | 750+ kWp | from 550,000 EUR |
Per kilowatt-peak of installed capacity, you require approximately 5 to 7 square metres of roof space depending on the module type. A mid-sized commercial business with 200 kWp therefore needs around 1,000 to 1,400 square metres of space.
With our PV Energy Planner you can make an initial estimate of the optimal system size for your location.
Tax Advantages for Business Owners
One of the biggest advantages of commercial PV systems over private systems lies in the tax planning opportunities available.
VAT Input Tax Deduction
As a business owner, you can claim the VAT on the acquisition costs of the PV system as input tax. On a net investment of 200,000 euros, the actual financial burden is reduced by 38,000 euros of VAT, which you reclaim from the tax office.
Depreciation (AfA)
Commercial solar systems are depreciated on a straight-line basis over 20 years. This means you can claim 5 percent of the acquisition costs as a business expense each year. In combination with the special depreciation under Section 7g of the German Income Tax Act (EStG), small and medium-sized enterprises can write off up to 40 percent of the investment costs in the first year.
Investment Allowance (Investitionsabzugsbetrag, IAB)
Even before the acquisition, you can form an investment allowance of up to 50 percent of the anticipated acquisition costs. This reduces your taxable profit already in the year in which you plan the investment -- before the system has even been installed. The IAB must be dissolved by the actual investment within three years.
Trade Tax Treatment
Income from operating a PV system is in principle subject to trade tax (Gewerbesteuer). However, the investment costs can reduce the trade-tax profit via depreciation. For most commercial businesses, the PV system is part of the business assets anyway, so no additional tax complexity arises.
Financing Commercial Solar Systems
Financing is often the biggest hurdle when deciding to invest in a commercial PV system. Fortunately, several models are available that cover different needs.
Equity Financing
Those with sufficient reserves can finance the PV system from their own funds. The advantage: no interest burden, full control, and the highest total return over the system's lifetime. The payback period for commercial systems is typically 6 to 10 years.
Bank Loans and KfW Subsidised Loans
KfW offers low-interest loans for commercial PV systems through Programme 270 ("Renewable Energies -- Standard"). The terms are frequently below market interest rates, and repayment-free start-up years are possible. Commercial banks and savings banks now also have standardised financing products for solar systems in their portfolios.
Leasing
With PV leasing, the lessor remains the owner of the system. You pay a monthly leasing rate and use the electricity generated. At the end of the lease term, you can often take over the system at a residual value. The advantage: no equity required, and leasing rates are fully deductible as a business expense.
Power Purchase Agreement (PPA)
In the PPA model, an investor installs the PV system on your roof and sells you the generated electricity at a contractually fixed price. You bear no investment risk and still benefit from cheaper electricity. The disadvantage: the price advantage over grid electricity is smaller than with your own system, since the investor factors in their return.
| Financing model | Equity requirement | Tax deductibility | Return |
|---|---|---|---|
| Equity | High | AfA, IAB, input tax | Highest |
| KfW loan | Low | AfA, IAB, input tax, interest | High |
| Leasing | None | Leasing rates as business expense | Medium |
| PPA | None | Electricity costs as business expense | Low (no ownership) |
Example Calculation: PV System for a Commercial Business
To make the economics tangible, let us look at a concrete example: a mid-sized manufacturing business with a production hall and an office building.
Starting Situation
| Parameter | Value |
|---|---|
| Annual electricity consumption | 120,000 kWh |
| Current electricity price | 0.27 EUR/kWh (net) |
| Annual electricity costs | 32,400 EUR |
| Available roof area | 1,200 m² |
Planned PV System
| Parameter | Value |
|---|---|
| System size | 150 kWp |
| Annual yield | approx. 142,500 kWh |
| Self-consumption share | 65 % (92,625 kWh) |
| Grid feed-in | 35 % (49,875 kWh) |
| Investment costs (net) | 165,000 EUR |
Annual Returns and Savings
| Item | Amount per year |
|---|---|
| Savings from self-consumption (92,625 kWh x 0.27 EUR) | 25,009 EUR |
| Feed-in tariff (49,875 kWh x 0.07 EUR) | 3,491 EUR |
| Total return per year | 28,500 EUR |
| Operating costs (maintenance, insurance, meter fee) | -2,500 EUR |
| Net return per year | 26,000 EUR |
Payback Period
| Key figure | Value |
|---|---|
| Investment costs (net, after VAT input tax deduction) | 165,000 EUR |
| Annual net return | 26,000 EUR |
| Simple payback period | approx. 6.3 years |
| Total return over 25 years (without electricity price increases) | approx. 650,000 EUR |
| Total return over 25 years (with 3 % annual electricity price increase) | approx. 820,000 EUR |
This example calculation shows: even without taking into account tax advantages such as special depreciation and the IAB, the system pays for itself in just over six years. Over the entire lifetime of 25 years, it generates many times the investment costs.
Approvals and Technical Requirements
Planning Permission
PV systems on existing buildings are exempt from planning permission in most German federal states, provided they are not installed on listed buildings and the structure can bear the additional load. For ground-mounted systems or systems above certain capacity thresholds, building permission may be required. Check with your local building authority regarding local regulations.
Grid Connection and Registration
Every PV system must be registered with the responsible grid operator. For commercial systems above 30 kWp, feed-in management is generally required, which allows the grid operator to reduce feed-in during grid overload. The system must also be registered in the core energy market data register (Marktstammdatenregister) of the Federal Network Agency (Bundesnetzagentur).
Technical Requirements
- Inverters: Commercial systems use string inverters or central inverters. The choice depends on the system size and roof geometry.
- Metering concept: Commercial systems generally require a bidirectional meter and, if applicable, a separate generation meter.
- Lightning protection: For commercial buildings with existing lightning protection, the PV system must be integrated into the lightning protection concept.
- Fire protection: Fire brigade disconnection switches and isolation devices are required for commercial systems to enable emergency responders to work safely.
- Monitoring: A professional monitoring system enables real-time surveillance of system performance and early detection of faults.
Maintenance and Operation
Commercial PV systems should be serviced at least once a year by a qualified contractor. Maintenance includes a visual inspection of the modules, checking the electrical connections, and inspecting the inverters. Annual maintenance costs amount to approximately 1 to 1.5 percent of the investment costs.
Frequently Asked Questions
From what company size does a commercial solar system pay off?
A commercial PV system is generally worthwhile from an annual electricity consumption of approximately 20,000 kWh and an available roof area of at least 150 square metres. This corresponds roughly to a small trade business. What matters less is the size of the company and more the relationship between available roof area, electricity consumption, and consumption profile. Even smaller businesses can achieve attractive returns with a well-sized system.
How long does it take to install a commercial PV system?
From the initial enquiry to commissioning, commercial PV systems typically take 3 to 6 months. The actual roof-mounted installation takes between one and four weeks depending on system size. The largest time investment comes from the planning phase, the structural assessment, grid operator approval, and procurement of components. Operations can generally continue without interruption during installation.
What funding programmes are available for commercial solar systems?
In addition to the nationwide feed-in tariff under the Renewable Energy Sources Act (EEG) and KfW subsidised loans (Programme 270), there are numerous funding programmes at state and municipal level. Some German federal states offer grants for battery storage or advisory services. Furthermore, companies can use the investment allowance (IAB) and special depreciation, which, while not classic subsidies, represent a significant tax relief. An energy consultant or tax adviser can help you identify all available funding opportunities.
Can I install a PV system on a rented commercial roof?
Yes, this is generally possible, but requires the landlord's consent and a clear contractual arrangement. Key points are the rights of use for the roof, the duration of the agreement, the obligation to restore the roof to its original condition, and liability for damages. Alternatively, the landlord can install the system themselves and offer you the electricity at a reduced price via a tenant electricity model or a PPA. This arrangement can be economically attractive for both parties.
How does a PV system affect the value of my commercial property?
A professionally installed PV system generally increases the value of a commercial property significantly. Studies show a value increase of 3 to 5 percent, depending on system size, condition, and remaining useful life. In addition, commercial properties with their own energy generation are increasingly favoured on the rental and sales market, as they offer lower ancillary costs and a better energy balance. This is particularly relevant in view of the rising requirements of the German Building Energy Act (Gebäudeenergiegesetz).
Take the Next Step Now
A solar system for your business is more than an ecological decision -- it is a sound economic investment with attractive returns, tax advantages, and long-term planning certainty. The conditions for commercial PV systems are currently as favourable as they have rarely been before.
If you would like to know what potential your business premises offers, use our free PV Energy Planner for an initial simulation. On our commercial page you will also find further information, industry-specific solutions, and the option to request a no-obligation quote.
Make your business more independent, more sustainable, and economically stronger -- with solar energy from your own roof.