Does solar pay — after tax?
Germany runs two photovoltaic worlds with exactly opposite rules. Tell us which one you are in and we will run the right one.
The system nets €862 in year one — that is 6.9 % of the purchase price.
It has paid for itself after 14.3 years. Across the whole term that corresponds to 4.6 % per year.
Output, year 1
9,500 kWh
of which self-consumed
1,200 kWh
electricity saved
€373
exported (7.70 ct)
€639
Limited by your consumption
Your household cannot absorb any more solar electricity directly. Every additional module therefore goes to the grid for around 7 ct instead of saving around 31 ct — the system is already large enough for this consumption. 37 % of the benefit comes from self-consumption.
Tax: exempt — and therefore nothing is deductible
Up to 30 kWp per unit the entire income is tax-free under § 3 Nr. 72 EStG, exports and self-consumption alike. That is exactly why § 3c Abs. 1 EStG rules out every deduction: no depreciation, no special depreciation, no investment deduction, no maintenance and not the interest on a loan either. The relief is instead the zero VAT rate on purchase under § 12 Abs. 3 UStG — already inside the prices above. There is deliberately not a single tax line in this calculation.
Calculated at €1,250 per kWp. The 2026 market is roughly 1,000–1,600 € per kWp without a battery — get several quotes, the spread is real.
Property, an equity fund, savings and a commercial solar direct investment after tax, on identical capital. A system on your own roof is deliberately absent there: it presupposes a roof, so it is not a pure capital decision.
A scenario calculation — not tax or investment advice. Not modelled: heat pump, wallbox, dynamic tariffs, inverter replacement beyond the running costs, roof renewal and curtailment. Calculated unfinanced — the interest would not be deductible under § 3c Abs. 1 EStG anyway. The self-consumption and self-sufficiency figures are assumptions; a reliable value only follows from your actual load profile.
Almost everything written about "writing solar off against tax" in Germany conflates two regimes that exclude one another. Up to 30 kWp per unit the income is tax-free under § 3 Nr. 72 EStG — and precisely because it is tax-free, § 3c Abs. 1 EStG forbids every connected deduction: no depreciation, no special depreciation, no investment deduction, not even the financing interest. The relief in that regime is the zero VAT rate on purchase under § 12 Abs. 3 UStG, a discount at the till rather than a depreciation scheme. Above that threshold — commercial roof, ground-mounted, direct investment — the system is a Gewerbebetrieb and fully taxable, which is why the entire toolkit opens up instead: a 50 % investment deduction under § 7g Abs. 1, 40 % special depreciation under § 7g Abs. 5, and the declining-balance rate under § 7 Abs. 2. In exchange there is no ten-year clock as there is on a let property: the gain on business property is always taxable. This calculator models both cases, using the § 48 EEG feed-in rates for commissioning from August 2026 and the tranche structure that pays them per capacity band.
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Common questions
Can I write a solar system off against tax?
Up to 30 kWp per unit: no, and that is not an oversight. The income is tax-free under § 3 Nr. 72 EStG, and because it is tax-free § 3c Abs. 1 EStG rules out every deduction — depreciation, special depreciation, the investment deduction, maintenance, even the financing interest. What exists instead is the zero VAT rate on purchase under § 12 Abs. 3 UStG. Above 30 kWp, for commercial systems and direct investments, it inverts completely: everything is taxable and therefore everything is deductible.
Why does a bigger system not earn more?
Because your consumption decides this, not your roof. A self-consumed kilowatt-hour saves about 31 ct of purchase price; an exported one earns about 7 ct — more than a fourfold difference. But how much you can consume yourself is bounded twice: by what the system generates at the moment you draw power, and by what your household draws at all. Once the second ceiling is reached, every further module goes to the grid instead of the socket. The calculator tells you which of the two binds in your case.
Is a battery worth it?
It is an investment in its own right and is calculated as one here. A battery raises self-consumption but costs 500–800 € per kWh of capacity, and that has to be earned back out of the spread between the electricity price and the feed-in tariff. Often a small battery pays and a large one no longer does — because self-consumption is already at the ceiling of what you use and extra capacity adds nothing. The calculator prices the battery separately instead of hiding it in a package price.
What is the difference between surplus and full feed-in?
With surplus feed-in you consume first and export only the rest, which pays 7.70 ct/kWh up to 10 kWp. With full feed-in everything goes to the grid and the EEG pays considerably more: 12.22 ct up to 10 kWp and 10.24 ct up to 100 kWp. For a normal household surplus feed-in still wins almost always, because a self-consumed kilowatt-hour is worth around 31 ct — more than any tariff. This calculator therefore models surplus feed-in.
What is a solar direct investment, and what is the catch?
You buy a section of a commercial solar park and become its operator, with every tax consequence that follows. The prospectuses lead with "77 % written off in the first year", which is arithmetically true and still misleading: the total volume of depreciation remains exactly the investment, it is only pulled forward. On sale the tax office recovers the gap between book value and market value, at any point in time, because there is no speculation period here. The calculator shows both and quantifies what the accelerated depreciation is actually worth in your case — not rarely it is negative.
Why is the advertised return higher than yours?
Because offers usually quote the first year's distribution rather than the return. A solar system is a wasting asset with little residual value: much of what it pays out each year is your own capital flowing back. Discount the payments across the full term and take off the tax, and what typically remains is a fraction of the advertised number. Both figures are shown side by side here.
Is this investment advice?
No. The calculator evaluates the numbers you enter and names no product, no provider and no specific solar park. It tells you what follows arithmetically from your own assumptions — not what you should do.