Respuesta rápida
With self-consumption in Spain, your surplus compensation only reduces the variable (energy) term of your bill — never the fixed term (contracted power, tolls, taxes). To maximise solar ROI: right-size contracted power post-install (often you can lower it), compare surplus-compensation €/kWh (usually €0.05–€0.15), and consider a 'virtual battery' if you regularly over-produce.
En 30 segundos
- ✓Locate the 'Potencia Contratada' section and compare it with your peak usage in the distributor's portal.
- ✓Check the 'Excedentes' (Surplus) line to see the price per kWh your provider pays you.
- ✓Identify any 'Servicios Adicionales' or maintenance fees that don't relate to energy consumption.
Is your solar investment underperforming?
Upload your bill and get a forensic breakdown of your fixed terms and surplus compensation in 30 seconds.
Why you can trust it
- Free and no signup
- AI trained on the Spanish market (~30s)
- Privacy-first: ephemeral processing (we don't store your bills)
Transparencia y fuentes
Autoría
Equipo ahorr.ai
Auditoría energética (España)
Actualizado: 21 de abril de 2026
Metodología orientada a decisión: separar coste fijo/variable, detectar extras y comparar opciones con números claros.
Metodología
- →Separamos coste fijo (potencia/término fijo), energía y cargos/impuestos.
- →Buscamos sobrecostes típicos: potencia sobredimensionada, servicios extra, lecturas estimadas.
- →Damos pasos accionables (qué tocar primero) con ejemplos orientativos, no promesas.
- →Enlazamos fuentes oficiales y marcamos lo que puede variar por comercializadora.
Información orientativa (España). Comprueba condiciones con tu comercializadora: precios, peajes, cargos e impuestos pueden variar.
Typical Causes (And How They Appear in the Breakdown)
Understanding your bill requires looking past the total amount and into the specific line items.
Fixed vs Variable
Your bill is split into the fixed term (power and taxes) and the variable term (energy consumed). Solar panels primarily reduce the variable term. If your fixed term is too high, your savings will always have a ceiling.
Invisible Extras
Many providers sneak in 'protection' or 'emergency' services. In a self-consumption setup, these 'vampire' costs often negate the financial benefit of the energy you export to the grid.
What to Review in Your Bill (The Paper Trail)
To diagnose the health of your installation's ROI, you need to track these specific numbers.
- →The 'Facturación por potencia' line: Are you paying for more than you use?
- →The 'Descuento por excedentes': Is the price per kWh fair (usually >0.08€/kWh)?
- →The 'Cargos y Peajes': These are regulated but can be optimized by adjusting your profile.
Real Case: The Culprit Wasn't the kWh
In our forensic audits, we often find that the price of energy is secondary to the structure of the contract.
The Clue
A user noticed that even in summer with maximum production, their bill never dropped below 40€. The autopsy showed 4.6 kW contracted while their inverter logs showed they never drew more than 2.5 kW from the grid.
The Correction
By lowering the power to 3.3 kW and removing a 7€ maintenance fee, the user saved over 150€ per year without changing their consumption habits.
Quick Solution: Autopsy with ahorr.ai
Stop guessing and let technology do the forensic work for you.
What it Detects
Our IA scans for oversized power, hidden services, and compares your surplus compensation against the 'Price Guardian' database of current Spanish rates.
What You Do with the Report
You receive a clear PDF with specific actions: 'Lower power to X', 'Cancel service Y', or 'Switch to provider Z for better surplus rates'.
Checklist for Electricity Bills with Self-Consumption
- ✓Locate the 'Potencia Contratada' section and compare it with your peak usage in the distributor's portal.
- ✓Check the 'Excedentes' (Surplus) line to see the price per kWh your provider pays you.
- ✓Identify any 'Servicios Adicionales' or maintenance fees that don't relate to energy consumption.
- ✓Verify the 'Término Fijo' cost; this is paid regardless of how much solar energy you produce.
- ✓Compare your surplus compensation rate against the current PVPC or free market average.
- ✓Decide if a 'Virtual Battery' service would be more profitable than simple surplus compensation.
Symptoms of an Inefficient Self-Consumption Bill
| Symptom | Likely Culprit | Recommended Action |
|---|---|---|
| High bill despite high production | Oversized Contracted Power | Lower your kW power setting |
| Surplus credit is very low | Poor Compensation Rate | Switch to a provider with better surplus prices |
| Fixed costs exceed 30€ | Hidden Maintenance Services | Cancel non-essential insurance or services |
| Negative balance not possible | Lack of Virtual Battery | Look for 'Hucha Solar' or Virtual Battery plans |
Fixed terms cannot be compensated below zero unless you use a Virtual Battery service.
The Swedish Family in Costa Brava: Solar Without Power Right-Sizing
A Swedish family with a new 4.2 kWp PV installation on their 120 m² Costa Brava holiday home couldn’t understand why summer bills still hit €55 despite strong production. Audit showed 5.75 kW contracted while the inverter never drew more than 2.9 kW from the grid, plus a €6.20/month 'home protection' add-on. Downgrading power and cancelling the service added around €140/year of real savings on top of surplus compensation.
Hallazgos
- ✓Contracted 5.75 kW post-PV vs. real grid draw peak of 2.9 kW.
- ✓€6.20/month home-protection add-on never used.
- ✓Surplus compensation price of €0.06/kWh — below current top market offers (€0.10–€0.15).
No bill handy?
You can still create a profile to monitor market prices and receive alerts when a better surplus rate appears.
Preguntas frecuentes
Privacy-First Auditing
We don't store your data. No commercials will call you. Just pure data for your decision-making.
Disclaimers
- Informational tool; not financial advice.
- We don’t guarantee savings: these are estimates.