How will an in-house solar power system pay off for your business in 2026?
Self-consumption instead of grid purchase: Solar power from your own roof costs 6–14 ct/kWh—compared to 18–27 ct/kWh from the grid. Planning, construction, and operation—all from a single source.
Generation Costs for Solar Power from One's Own Roof (Fraunhofer ISE, 01/2026)
Payback period with at least 50% self-consumption
Depreciation over 2 years via IAB + special depreciation (§7g EStG)
Short and to the point: Your own PV system reduces your business’s electricity costs from 18–27 ct/kWh for grid-purchased power to 6–14 ct/kWh for self-generated solar power. With ≥ 50% self-consumption, it pays for itself in about 6–10 years. Under Section 7g of the German Income Tax Act (EStG), you can combine an investment tax credit of up to 50% with a 40% special depreciation allowance.
This guide is intended for companies that want to generate their own electricity instead of purchasing it at high costs—from manufacturing and logistics to agriculture. It provides a step-by-step overview of cost-effectiveness, system size, tax incentives, financing, and the process leading up to commissioning. As a system operator, you’ll use the electricity you generate on-site, feed the surplus into the power grid, and at the same time drive the energy transition within your own operations.
How does my company benefit from having its own solar power system?
A home solar power system pays for itself through self-consumption: Every kilowatt-hour you consume yourself replaces expensive grid electricity. Instead of paying 18–27 ct/kWh, you pay only the generation costs of 6–14 ct/kWh. You can sell any surplus back to the grid for a fee. The higher your self-consumption, the shorter the payback period.
Self-consumption: The portion of solar power that the business uses directly itself—the most significant factor in cost-effectiveness.
Grid supply: Electricity that you continue to purchase from the public grid (commercial electricity rate).
kWp (kilowatt-peak): the system's installed capacity under standard conditions.
Payback period: The period of time it takes for the savings to cover the investment.
Three factors determine the calculation
Cost-effectiveness is determined by three factors: the replaced electricity price (the difference between the grid purchase price and generation costs), the self-consumption rate, and the tax benefits under Section 7g of the Income Tax Act (EStG). A battery storage system further increases self-consumption. Details on storage integration: Battery storage systems.
From the Initial Idea to Your Own Solar System in 6 Steps
It takes about 4 to 9 months from the initial inquiry to commissioning. Logic Energy handles every step—from load profile analysis to grid connection and construction (Logic Glas GmbH) to registration. You’ll receive a turnkey system and yield monitoring starting on day one.
Load Profile & Roof Inspection
Energy Consumption + Roof Structural Analysis · 1–2 weeks
Analysis & Forecast
kWp + Cost-Effectiveness · 2–3 Weeks
Offer & Financing
Purchase, KfW, or Leasing · 2–4 weeks
Power Connection
135 kW and up, medium voltage · 2–6 months
DC/AC Installation
Installation by Logic Glas · 4–10 weeks
Commissioning & MaStR
Acceptance + Registration · 1–2 weeks
Entry in the Market Master Data Register within one month (Section 5 MaStRV); for systems of 100 kWp or more, the direct marketing requirement applies (Section 21b EEG 2023). Remuneration for surplus electricity: EEG remuneration 2026.
Planning: Site analysis, structural analysis of the roof, and feasibility study
Planning a photovoltaic system involves a site analysis and afeasibility study; prior to installation, a structural analysis of the roof anda feasibility assessment must also be conducted. The utility company is contacted early on to verify the feed-in capacity (grid connection application). Depending on the size and location, a building permit may be required for large commercial PV systems; for historic buildings, historic preservation regulations must also be observed.
Installation and commissioning by a licensed electrician
A licensed electrician is responsible for the proper installation of the PV modules and inverters, as well as for grid registration and commissioning. The solar cells absorb sunlight and generate direct current, which the inverter converts into grid-compatible alternating current. Once the system is commissioned, it is entered into the market master data registry, and yield monitoring begins.
Who benefits from having their own solar power system?
Businesses with high daytime electricity consumption that aligns with sunlight hours—that is, production, cooling, machinery, or air conditioning that runs during the day—benefit the most. The better consumption and generation align, the higher the self-consumption rate and the faster the payback period.
| Industry | Typical size | Self-consumption without storage | with storage |
|---|---|---|---|
| Manufacturing & Industry | 200–800 kWp | 55–70% | 75–85% |
| Logistics & Warehousing (Roof-Mounted Systems) | 300–1,000 kWp | 40–60% | 65–80% |
| Retail & Crafts | 50–200 kWp | 45–65% | 70–80% |
| Agriculture & Dairy Farming (Agri-PV) | 100–500 kWp | 50–70% | 75–85% |
| Hotels, Clinics & Nursing Care | 100–400 kWp | 35–50% | 60–75% |
| Guideline values based on load profile. Source: Helm Group, 2024 portfolio data; Section 2 of the EEG 2023 (priority for renewable energy). Storage significantly increases self-consumption. | |||
Cost-effectiveness: What savings are realistic?
A realistic savings figure is around 8–15 ct per kilowatt-hour consumed on-site—the difference between the commercial electricity rate and the cost of PV generation. A 130-kWp rooftop system (net investment of approximately €120,000) covers a significant portion of daily electricity needs with 60% self-consumption and saves many times the investment over its lifetime.
What size system is right for my business?
As a rule of thumb, allow for about 1.3 kWp per 1,000 kWh of annual electricity consumption, based on a high level of self-consumption. Key factors include the load profile, the usable roof area (about 5–6 m² per kWp), and the budget. The following table provides some initial guidance.
| Annual consumption | Recommended Power | Roof area (approx.) | Net investment (approx.) |
|---|---|---|---|
| 50,000 kWh | ~65 kWp | ~350 m² | ~70.000 € |
| 100,000 kWh | ~130 kWp | ~700 m² | ~120.000 € |
| 250,000 kWh | ~325 kWp | ~1,750 m² | ~290.000 € |
| 500,000 kWh | ~650 kWp | ~3,500 m² | ~560.000 € |
| 1,000,000 kWh | ~1,000–1,300 kWp | ~6,500 m² | ~€1.0 million |
| Guideline values (Logic Energy model calculation for 2026). The tender requirement for grid feed-in applies to systems of 1 MWp or more (§22 EEG 2023). Large open spaces: open-space installations. | |||
Tax Treatment of the Solar Power System: Section 3, No. 72 of the Income Tax Act (EStG), Income Tax, and Trade Tax
When it comes to photovoltaics and taxes, it’s worth starting with an overview, as different rules apply to small and large systems. Small systems have benefited from extensive tax breaks since the 2022 Annual Tax Act; a commercial photovoltaic system for on-site consumption, on the other hand, is usually subject to regular taxation—and that’s precisely where the depreciation benefits come into play.
Tax-Exempt Income and Withdrawals from Small Investments (Section 3, No. 72 of the Income Tax Act)
Under Section 3, No. 72 of the Income Tax Act (EStG), income and withdrawals from the operation of a photovoltaic system are exempt from income tax if the gross installed capacity does not exceed certain limits; the tax exemption applies retroactively as of January 1, 2022. For systems commissioned after December 31, 2024, a uniform limit of 30 kW peak per residential or commercial unit applies—regardless of the type of building. For older systems, the limit is 30 kW peak for single-family homes and non-residential buildings, or 15 kW peak per unit for multi-family homes and other buildings. A prerequisite is the intent to make a profit—if this is lacking, the tax office classifies the activity as a hobby. Ground-mounted systems are excluded from this tax exemption.
Multiple PV systems and the 100-kW-peak limit
If a taxpayer operates multiple PV systems, their capacities are aggregated to determine whether the 100 kW peak limit is exceeded (ground-mounted systems are excluded from this calculation). If this limit is exceeded, the tax exemption no longer applies—which is particularly relevant for businesses with multiple locations or buildings.
Zero VAT Rate
Effective January 1, 2023, a zero VAT rate of 0% applies to the purchase and installation of eligible systems (Section 12(3) of the German Value-Added Tax Act (UStG)). The requirements are automatically deemed met for systems up to 30 kW peak according to the Market Master Data Register—this applies to typical systems on single-family homes, small commercial properties, and balcony power plants. The Federal Ministry of Finance has set out the details in a BMF circular; when purchasing at the zero-rate, value-added tax is also waived on the self-consumption of the electricity generated.
Operating a Photovoltaic System for Commercial Use: Determining Profit Using the EÜR Method and Schedule G
A solar power system installed by a business for its own consumption is usually well over 30 kW peak and thus exceeds the limit set forth in § 3 No. 72 of the German Income Tax Act (EStG). It is therefore not tax-exempt: The sale of surplus electricity and the business’s own consumption result in income from commercial operations, which is subject to income tax for sole proprietors and self-employed individuals and to corporate income tax for corporations. The operation itself is considered a commercial activity. In practice, profits are determined using the income-surplus method (EÜR) along with ongoing bookkeeping and are reported in the tax return via Schedule G. For value-added tax (VAT), the standard taxation regime applies with input tax deduction.
The plant operator reports the operation of such a facility to the tax office using the tax registration questionnaire—now handled entirely digitally via ELSTER, a concrete example of digitalization in tax administration. Trade tax is only due if business income exceeds the annual exemption threshold of €24,500; small systems up to 30 kW peak are exempt from trade tax under Section 3(32) of the Trade Tax Act (GewStG) in any case.
| Aspect | Small-scale system (≤ 30 kW peak per unit, max. 100 kW peak) | Commercial self-consumption system (usually > 30 kW peak) |
|---|---|---|
| Income Tax | tax-exempt under § 3 No. 72 of the Income Tax Act (EStG) | Taxable — Income from Business Operations |
| Sales Tax (Purchase) | Zero tax rate 0% (Section 12(3) of the German Value-Added Tax Act (UStG)) | Standard taxation with input tax credit |
| Business Tax | exempt (Section 3, No. 32 of the Trade Tax Act) | only if business income exceeds €24,500 |
| Section 7g of the Income Tax Act (IAB / Special Depreciation) | Not applicable (tax-exempt) | fully usable |
| Profit Determination | Generally none (Appendix G / EÜR not applicable) | EÜR + Schedule G |
| Overview; no case-by-case review. Governing provisions: Section 3(72) of the Income Tax Act (EStG), Section 12(3) of the Value-Added Tax Act (UStG), Section 3(32) of the Trade Tax Act (GewStG), Federal Ministry of Finance (BMF) circular (as of 2026). Have a tax advisor verify applicability in your specific case. | ||
Tax Benefits: Section 7g of the Income Tax Act (EStG), special depreciation, and straight-line depreciation
Because the commercial self-consumption system is subject to tax, its acquisition costs can be depreciated in a targeted manner—which significantly reduces income tax in the early years. Three measures reduce the tax burden: the investment deduction (IAB, Section 7g(1) of the Income Tax Act) of up to 50% upfront, the special depreciation (Sonder-AfA, Section 7g(5) of the Income Tax Act) of 40% of the acquisition costs, and straight-line depreciation over 20 years. Combined, these allow for up to 77.5% to be depreciated in the first two years.
| Instrument | Height | Legal basis | Requirement |
|---|---|---|---|
| Investment Tax Credit (ITC) | up to 50% in advance | §7g, para. 1, EStG | Profit ≤ 200,000 €; total amount: max. 200,000 € |
| Special depreciation | 40 % | §7g(5) of the Income Tax Act (Growth Opportunities Act, March 27, 2024) | Purchases effective January 1, 2024 |
| Straight-line depreciation | 5% per year | §7 EStG / BMF Depreciation Schedule | Useful life: 20 years |
| Declining-balance depreciation | as an alternative to straight-line depreciation | Immediate Investment Program (Federal Law Gazette 2025 I No. 161) | Purchase: July 1, 2025–December 31, 2027 |
| Sources: gesetze-im-internet.de (§7g, §7 EStG); BMF letter; BFH X R 16/23 & X R 17/23 (October 1, 2025). A tax advisor should verify whether these provisions apply in individual cases. | |||
Calculation example: up to €32,550 in tax savings
For a €100,000 investment and a marginal tax rate of 42%, the tax relief can amount to approximately €32,550 in the first two years (internal sample calculation by the Helm Group). The IAB amounts to up to 50% of the planned acquisition costs of a single investment; the maximum total IAB amount per taxpayer as of the balance sheet date is limited to €200,000 (Section 7g(1), sentence 4, of the German Income Tax Act (EStG)).
Note the 90% minimum usage requirement: For IAB and special depreciation, the asset must be used almost exclusively for business purposes—for PV systems that feed electricity into the grid, the scope of this requirement is disputed (BFH III R 39/25, III B 24/24 pending). Complete guide: Save on taxes with photovoltaics—IAB, special depreciation, and declining-balance depreciation.
Financing: Equity, KfW 270, and leasing
A typical structure consists of a mix of 20–30% equity and 70–80% debt. There are four options to choose from—the decision directly affects the tax benefits available, particularly under Section 7g of the German Income Tax Act (EStG).
Equity & Primary Bank
20–30% equity; the remainder through the company's primary bank. Full use of IAB and special depreciation, since the company becomes the owner.
KfW 270
"Renewable Energy – Standard" promotional loan of up to €150 million, with a term of up to 30 years (kfw.de/270). Section 7g remains applicable.
Leasing
Preserves liquidity and has no impact on the balance sheet (off-balance). Economic ownership remains with the lessor—Section 7g of the German Income Tax Act (EStG) does not apply.
Hire Purchase
Transfer to economic ownership — Section 7g of the Income Tax Act (EStG) remains applicable. A good alternative when liquidity is tight.
If you’d rather invest in photovoltaics than operate a system yourself, the Helm Group offers a profit-sharing model (contract partner: mediplan Helm e.K.). Learn more: Become a PV Investor and PV Investment 2026.
Your Own PV System or a PPA Model?
With an in-house system, the business owns the system and uses the electricity directly—maximizing savings, but the investment and operational responsibilities fall on the company. With a PPA (Power Purchase Agreement), a third party supplies the solar power at a fixed price, without requiring any investment on your part. A hybrid model combines both approaches.
| Feature | Own facility | PPA Model | Hybrid model |
|---|---|---|---|
| Investment | by the company | none | in part |
| Electricity Price Advantage | maximum (generation costs) | fixed PPA price | high |
| Tax Benefit Under Section 7g | usable | unavailable | pro rata |
| Operator Responsibilities | during operation | from the provider | shared |
| Capital Commitment | high | none | medium |
| Getting Started Without Equity: Solar Power Without Equity. Industry Case Study: Photovoltaics in Industry. | |||
Why Choose Logic Energy for Your Solar Power System?
At Logic Energy, everything comes from a single source: planning, permitting, grid connection, general contractor construction (Logic Glas GmbH), commissioning, maintenance, and monitoring. This level of integration reduces risks over the entire project lifespan and makes revenue predictable. High-quality N-type modules degrade at a rate of approximately 0.25–0.4% per year—below the industry median of about 0.5% (NREL).
Increasing Self-Consumption of Generated Electricity: Self-Sufficiency and Carbon Footprint
A battery storage system can increase the self-sufficiency rate from around 30% to as much as 70% and significantly boost the amount of generated electricity that is consumed on-site. Electricity generation is emission-free during operation and reduces the company’s carbon footprint—an increasingly important selling point for customers, banks, and within the supply chain. Learn more: Battery storage systems.
Everything under one roof
Planning, construction, operation, and maintenance all under one roof—no risk of coordination issues.
Lowest Electricity Costs
Self-consumption permanently lowers the price of electricity. Payback period: 7–12 years, depending on the profile.
N-type modules
Durable technology combined with a proprietary roof bridging system for industrial roofs.
Customized Invoice
Profitability forecast based on your actual load profile—no flat-rate figures.
Independence
Generating your own electricity protects against rising grid rates and provides planning certainty.
Battery Storage Integration
Optional storage increases self-consumption to up to 85%. Learn more.
Monitoring & Maintenance
Yield monitoring and O&M from the start of operations—the plant remains in top condition.
Tax Benefits & Value Appreciation
§7g leverage, property appreciation, and predictable electricity costs over 25+ years.
About Logic Energy and the Helm Group
Logic Energy is the photovoltaic brand of Logic Glas GmbH. As part of the Helm Group, which has been in existence since 1982, it supports companies with over 40 years of experience—from planning and general contracting through construction to operation. The project partner for investment and revenue models is the personally liable mediplan Helm e.K. (a registered merchant under §§ 1, 17, 19 HGB).
Conclusion: A Private Solar Power System for Your Business in 2026
A home solar power system permanently reduces electricity costs, pays for itself in 6–10 years if you use a significant portion of the electricity you generate, and offers tangible tax benefits under Section 7g of the German Income Tax Act (EStG). Key factors include a suitable load profile, proper sizing, and a partner who provides planning, construction, and operation all under one roof.
Next steps:
YMYL Disclaimer (displayed in the body): The information on this page is general in nature and does not constitute investment, tax, or legal advice. Return and savings figures are sample calculations based on real projects carried out by the Helm Group and do not guarantee future results. Every investment decision should be reviewed individually with a tax advisor. Tax regulations: Section 7g of the German Income Tax Act (EStG) as amended by the Growth Opportunities Act of March 27, 2024 (Federal Law Gazette I No. 108); BMF depreciation table. Proceedings are pending before the Federal Fiscal Court (BFH) regarding the scope of the IAB (III R 39/25, III B 24/24)—the legal situation may change. As of June 2026.
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FAQ
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Generally, yes: Section 7g(1) of the German Income Tax Act (EStG) allows up to 50% of the planned acquisition costs to be deducted in advance if the profit does not exceed €200,000. The maximum total IAB amount is capped at €200,000. A tax advisor should verify whether this applies in your specific case.
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For IAB and special depreciation (Sonder-AfA), the asset must be used almost exclusively (≥ 90%) for business purposes. For PV systems that feed electricity into the grid, the scope of this requirement is disputed; proceedings on this matter are pending before the Federal Fiscal Court (BFH) (III R 39/25, III B 24/24).
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Yes. Before construction begins, you must submit an application for a utility connection; for systems of 135 kW or more, the connection is made to the medium-voltage grid in accordance with TAB. In addition, the system must be entered in the Market Master Data Register within one month (§5 MaStRV).
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Yes. In the hybrid model, you use the electricity yourself and sell the surplus through a PPA or direct sales. For systems of 100 kWp or more, direct sales are mandatory (Section 21b of the EEG 2023).
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25–30 years and more. N-type modules degrade at a rate of about 0.25–0.4% per year (NREL). Inverters are usually replaced after 12–15 years; maintenance and monitoring ensure performance throughout the system’s lifespan.
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For business use, standard taxation generally applies: input tax credit on the purchase, and sales tax on electricity fed into the grid and drawn from it. A tax advisor can clarify the specifics of your individual case.
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Yes. Your company owns and operates the facility. You sell the surplus electricity through the EEG feed-in tariff or—mandatory for systems of 100 kWp or more—through direct sales.
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Usually not. The tax exemption under Section 3, No. 72 of the Income Tax Act (EStG) applies only up to 30 kW peak per residential or commercial unit and up to a maximum of 100 kW peak per taxpayer. A system for on-site consumption by a business generally exceeds these limits and thus generates taxable income from business operations. You must report the operation to the tax office using the tax registration questionnaire; for this purpose, you can utilize the §7g incentives (IAB, special depreciation) and the input tax credit.
In-Depth Content
Solar Power with Battery Storage: Increasing Self-Consumption
Save on Taxes with Solar Power — IAB, Special Depreciation, Declining-Balance Depreciation
Become a Solar Investor — Share in the Profits Instead of Operating the System Yourself
References
§7g EStG (gesetze-im-internet.de) — Investment deduction and special depreciation
§7 EStG (gesetze-im-internet.de) — Depreciation Allowance (Straight-Line Depreciation)
§5 MaStRV (gesetze-im-internet.de) — Mandatory Registration in the Market Master Data Registry
EEG 2023 (gesetze-im-internet.de) — §2, §8, §21b, §22 (Direct Marketing, Tender Process)
Letter from the Federal Ministry of Finance (BMF) dated June 15, 2022 — Tax Treatment of Photovoltaic Systems
BFH X R 16/23 & X R 17/23 (Oct. 1, 2025) — Investment Tax Credit
BFH III R 39/25 & III B 24/24 — pending, IAB coverage for PV
Fraunhofer ISE — Levelized Cost of Electricity for Photovoltaics (as of 01/2026): 6–14 ct/kWh
BDEW — Commercial Electricity Rates (as of 01/2026)
HTW Berlin — Energy Storage Inspection 2026
Federal Network Agency — Solar Auctions, 2026 Cap Values
kfw.de/270 — KfW Program “Renewable Energy – Standard”
NREL — Photovoltaic Degradation Rates (N-type modules ~0.25–0.4% per year)
Helm Group — Portfolio Data for 2024 & Logic Energy Model Projections for 2026
Last updated: June 16, 2026 · Edited by Logic Energy Legal Basis: §7g, §7 of the Income Tax Act (EStG) as amended by the Growth Opportunities Act of March 27, 2024 · §§ 1, 17, 19 of the Commercial Code (HGB) · Renewable Energy Act (EEG) 2023 · §5 of the Measure Regulation (MaStRV)