Several of our customers have already received limited tax audits from Hacienda for claiming the solar installation tax deduction… and later collecting a Next Generation grant on the same euros. This is not theory: Hacienda crosses the cadastral reference of your home with the Autonomous Community’s aid resolutions. If both appear, they catch you easily.
We told you when we stopped processing NextGen: the subsidised share is excluded from the deduction base. Anyone who ignored that advice has found, three years later, an expensive cocktail: amount to repay + late-payment interest + penalty, plus what they already paid external advisors for a NextGen file that takes years. Pathetic bureaucracy with real financial damage.
Nuance: PV NextGen (RD 477/2021) is not taxed in IRPF (DA 5ª.4 LIRPF; V0012-25) — it is not like MOVES. That is why in the tables below the grant enters in full. The problem is not IRPF on the aid: it is that it still pulls you out of the deduction base, takes years and, if you deducted too much, Hacienda regularises with interest and a penalty.
The rule is not optional
Additional provision 50ª, section 4, of Law 35/2006 on IRPF says you must subtract subsidised amounts (or amounts that will be subsidised by a final grant decision) from the deduction base.
The Directorate-General for Taxes has confirmed this in binding rulings:
- V2092-24 (26/09/2024): remove the granted amount from the base even if you have not collected it yet.
- V1125-25 (27/06/2025): if you already deducted and the grant arrives later, you must regularise (art. 59 IRPF Regulation): add to the tax due in the year of the grant what was wrongly deducted + late-payment interest.
This is not a slogan about “NextGen incompatibility”. It is IRPF law applied to your cadastral reference.
Concrete example: an €8,800 installation
Main home in the Valencian Community, improvement accredited for the 60% state band, plus the 40% regional band. On €8,800 that can reach 100% of the investment via deductions (€5,280 state + €3,520 regional).
Three years later a Next Generation grant of €6,500 arrives on that same installation.
Path A — you listened: deduction only, no NextGen
| Item | Amount |
|---|---|
| Installation cost | €8,800 |
| State deduction 60% | €5,280 |
| Regional deduction 40% | €3,520 |
| Total tax saving | €8,800 (100%) |
| NextGen file, advisors, waiting | €0 |
| Hacienda check for double benefit | None |
| Net cost of the installation | €0 |
End of story. Certificates, tax return, done.
Path B — you ignored us: 100% deduction plus NextGen
Year 1: you claim €8,800 in deductions. Years 1–3: you pay an external agency, paperwork, requests. Year 3: you collect €6,500. Soon after: a limited check. Hacienda crossed your cadastre with the aid resolution.
Correct base after the grant: 8,800 − 6,500 = €2,300. You should only have deducted on those €2,300:
- State 60% of €2,300 = €1,380
- Regional 40% of €2,300 = €920
- Correct total: €2,300
Because you claimed €8,800, the undue amount is €6,500 of deduction. That is not “repaying the grant”: it is repaying the tax saving you were not entitled to on those same euros. Then come interest and a penalty.
| Item | Amount |
|---|---|
| Installation cost | €8,800 |
| Deduction claimed at the start (60% + 40%) | − €8,800 |
| NextGen grant collected (years later) | − €6,500 |
| Tax to repay Hacienda (undue deduction) | + €6,500 |
| Late-payment interest (e.g. ~3 years) | + €900 |
| Penalty (realistic example; we have seen cases like this) | + €3,250 |
| NextGen advisors / agency (years of file) | + €1,200 |
| Real final cost for the customer | €5,350 |
| Real cost on Path A (deduction only) | €0 |
Practical result: the installation costs you €5,350 net in this example, versus €0 on Path A. You keep the grant — but you repay the undue tax saving, interest, penalty and agency fees. Being clever did not pay.
Why they catch you so easily (cadastral reference)
No cinematic inspection is required. The rules provide for information exchange between Autonomous Communities and the Tax Agency on final aid resolutions tied to energy-efficiency works, with the cadastral references affected. If your tax return shows the deduction for that home and the aid file shows the same plot/property, the cross-check is automatic.
What to do depending where you are
- You have not applied for NextGen / you can withdraw: keep the 100% deduction. That is what we recommend and process.
- Application pending, no final resolution: until there is a firm grant, the deduction base does not force a subtraction (ruling V1368-23). Consider withdrawing before they grant it.
- You already have a resolution / you already collected: do not deduct the subsidised share. If you already did, regularise in the tax year of the grant (undue tax + interest). Better with your advisor, before the letter arrives.
Our conclusion
PV Next Generation does not “add” to the deduction: even if it is IRPF-exempt, it competes on the same euros, takes years and leaves a cadastral trail. We have already seen the end of that film for customers who ignored the advice: limited check, amounts to repay, interest, penalty and money wasted on external advisors.
If you can choose, choose the clean tax route. If you are already tangled, talk to your tax advisor now — not when the letter arrives.
This is general information based on the LIRPF, the IRPF Regulation and DGT binding rulings; it does not replace personalised advice for your case. To review numbers for your installation, use the savings calculator or go back to Next Generation vs tax deduction.