Courtesy translation. The Spanish text at solargpu.es/fiscalidad is the one that applies.

Host taxation: what you declare, what you recover and what you don't have to do

You get paid for letting your node work. The Spanish Tax Agency has a name for that, and it is not "business owner": you are a lessor of movable property. That word decides everything that follows: you don't register as self-employed, you don't pay business activity tax (IAE), you recover the equipment's VAT and, while you depreciate it, you pay no income tax on what you earn.

Self-employed registration

NoYou lease an asset; you don't carry out an activity (Social Security Act art. 305.1)

Business activity tax (IAE)

€0Private individuals are exempt (Local Finance Act art. 82.1.c)

Income tax on the node

€0Almost four years: the node's depreciation (€715/year) exceeds what you earn (€617/year)

Equipment VAT

Comes back€577.50 on an SG1, in your first annual return (VAT Act arts. 92, 111, 115)

What you do

Three thingsSign the tax census registration we prepare, accept invoices in the app, and file your usual annual return

Assumptions in the examples: an SG1 at €2,750 plus €577.50 of VAT; 147 kWh per month at €0.35/kWh (€51 per month, €617 per year), rates in force on 15 September 2026; simplified depreciation table (26 % a year); a 30 % marginal rate as an example from the fifth year; each year's income tax is paid in the following year's return; the node's electricity is not deducted, since with solar surplus it is worth a few cents per kWh.

1. What you are to the Tax Agency, and why it matters
2. What happens every month
3. What happens every quarter and every year
4. The node's VAT comes back
5. The node's depreciation: why you pay no income tax
6. All together: an SG1 over ten years
7. If you live in the Basque Country
8. If you are a company or self-employed
9. Who does what
10. Sources, article by article

1What you are to the Tax Agency, and why it matters

The host contract is a lease of use: your node is yours, it is in your home and consumes your electricity, and SolarGPU operates it remotely and rents it to whoever needs compute. You sell nothing, serve no customers, set no prices and never touch the machine. What you earn is the rent from that lease, calculated per kilowatt-hour the node consumes while working.

The Spanish income tax act calls that investment income (article 25.4.c): "income from the leasing of movable property […] that does not constitute an economic activity". And it is not an economic activity because an economic activity is "the organisation, on one's own account, of means of production" (article 27.1), and the one organising the means here is SolarGPU, not you. That is why the contract puts two things in writing that protect you:

• You do not provide a service of hosting and compute. If you did, you would be a business: economic activity for income tax, activity registration and, in all likelihood, self-employed social security contributions.
• You do not sell energy. If you did, you would be an electricity producer, with its obligations, and you would stop being a self-consumer, which requires the energy to be for your own use. The energy is consumed by your own equipment: no kWh is sold to anyone.

With that classification the two obligations that scare anyone earning something on their own disappear. The RETA (the self-employed social security scheme) is for those who carry out "habitually, personally, directly, on their own account […] an economic activity" (Social Security Act art. 305.1); a lessor carries out no personal or direct activity. Don't count on the "I earn less than the minimum wage" argument: the Supreme Court said in 2025 and 2026 that this alone is not enough. What keeps you out is that you carry out no activity at all. The Business activity tax (IAE), for its part, exempts "natural persons, whether resident or not" (Local Finance Act art. 82.1.c): €0. All it requires is that the registration appears in the tax census, which is the same box filled in for VAT.

2What happens every month

Every month SolarGPU pays you the node's rent and, as lessor, you are a VAT taxable person: the invoice carries 21 % VAT, which you collect and then pay in, and a 19 % withholding on account of your income tax, which SolarGPU pays in for you and which is refunded in your annual return. You don't make the invoice: SolarGPU issues it on your behalf (self-billing, provided for in art. 5 of the Invoicing Regulation) and you accept it in the app.

VAT is neutral: the extra €10.71 you collect is the same amount you pay in later, and SolarGPU deducts it. No one gains or loses from it; it just circulates. What does leave you money is the withholding: €117 a year that the Tax Agency refunds you because, as you will see in point 5, you owe no income tax on the node.

3What happens every quarter and every year

Nothing else. No accounting books, no instalment payments, no Form 347 (transactions with withholding are reported through Form 193), no monthly contribution. The only thing there is, is VAT, and it is paperwork, not money; that is why we take it on.

4The node's VAT comes back

An SG1 costs €2,750 plus €577.50 of VAT: €3,327.50 on the invoice. As lessor you are a VAT taxable person and the node is assigned directly and exclusively to the lease — SolarGPU operates it; you use it for nothing else — so that VAT is deductible (VAT Act arts. 92 and 95). And it is even if you buy it before collecting the first rent, because the signed contract is the "objective element" that art. 111 requires to deduct VAT paid before the start.

1. You buy the node and sign the contract. You pay €3,327.50. With the contract and the invoice, we prepare your tax census registration (Form 036: lessor of movable property, heading 859). It is one signature.
2. The year's 303s come out "to be offset". Every quarter you charge about €32 and have €577.50 of input VAT: you pay nothing in and the balance in your favour goes down little by little.
3. In January you request the refund. In the fourth-quarter 303 you request the outstanding balance (art. 115.One). The Tax Agency has six months to pay it (art. 115.Three); in practice it usually arrives in spring.

The node stays below the €3,005.06 the law uses to call something a "capital good" for VAT purposes (art. 108.Two.4), so the deduction is final: there are no adjustments over five years. There is only one case in which the Tax Agency looks again: if one day you stop leasing it and keep it for private use, that transfer to your personal assets is a self-supply (art. 9.1.a) and you return VAT on what the equipment is worth then. If you sell it, the sale carries VAT, like any asset of a lessor.

5The node's depreciation: why you pay no income tax

From investment income you subtract "the expenses necessary to obtain it and, where applicable, the amount of the deterioration suffered by the assets" (Income Tax Act art. 26.1.b). The Regulation (art. 20) refers to the same rules as property rentals and without the limit that exists there for interest and repairs. The node's deterioration is deducted with the Tax Agency's simplified depreciation table: data processing equipment, 26 % a year, for a maximum of ten years.

In the common tax territory the negative result is not lost: art. 48.a integrates the income of the general tax base "without any limitation", so those €98 are subtracted from your salary or pension and save you a little more income tax (about €30 at a 30 % marginal rate). In the Basque Country the net stays at zero (point 7).

6All together: an SG1 over ten years

"Cumulative" is what you have in your pocket: in the first year you pay €3,327.50, recover €577.50 of VAT and earn €617. Each year's income tax on the node is paid in the following year's return, and the cumulative figure deducts it when it is paid; the final figure, +€2,306, is what remains after the tenth year's return. The withholding comes back in full for the first four years; from the fifth it covers part of the €185 and the rest is paid with the return. The 30 % marginal rate is an example: if yours is different, years 5 to 10 change and nothing else.

Assumptions in the examples: an SG1 at €2,750 plus €577.50 of VAT; 147 kWh per month at €0.35/kWh (€51 per month, €617 per year), rates in force on 15 September 2026; simplified depreciation table (26 % a year); a 30 % marginal rate as an example from the fifth year; each year's income tax is paid in the following year's return; the node's electricity is not deducted, since with solar surplus it is worth a few cents per kWh.

7If you live in the Basque Country

Álava, Bizkaia and Gipuzkoa have their own income tax, and the three provincial acts (Normas Forales) copy the state rule: the payment is investment income under article 37.c of each (NF 13/2013 of Bizkaia, NF 3/2014 of Gipuzkoa, NF 33/2013 of Álava), with the same expenses and the same node depreciation. The differences:

VAT is the same tax with the same rules (it is covered by the Agreement): Form 303 is filed with your provincial treasury instead of the AEAT, with the same figures and the same dates.

8If you are a company or self-employed

For a company or a professional the node is just another asset, and the tax treatment is the one you already know: no new obligation appears. What changes compared with a private individual is where the income goes, which depreciation table is used and whether there is withholding.

A self-employed person can also keep the node outside their activity — a physiotherapist with panels at home, for example —: then they are taxed exactly like a private individual, and the only thing to decide is in which box of Form 036 the lease is declared. SG2 and SG70 nodes are almost always bought by a company, which is why their prices are shown excluding VAT.

9Who does what

10Sources, article by article

Version 1.0, 16 September 2026. We will publish changes at this same address with their date. Questions: hola@solargpu.es.