Solar panels produce most of their energy around midday. If your home or business uses less than the panels produce at that moment, the extra energy flows into the grid. That energy is called surplus, and in Spain it can be deducted from your bill through simplified surplus compensation (compensación simplificada de excedentes).

This guide explains how it works, who qualifies, and why it matters when you decide how big your system should be.

What simplified compensation is

It is one of the self-consumption schemes set out in Spain's Royal Decree 244/2019. Instead of selling the extra energy as a producer, your electricity retailer values it in euros and subtracts it from the cost of the energy you buy from the grid in the same billing period.

It is the most common option for homes, small businesses and farms because you do not need to register as an energy producer or file energy-sale returns.

Main requirements

To use simplified compensation, the system must meet these conditions, among others:

  • The energy must come from renewable sources, such as solar.
  • The total capacity of the associated generation systems cannot exceed 100 kW.
  • You need a supply contract with an electricity retailer, which applies the compensation.
  • A surplus compensation contract or agreement must be signed.
  • The system cannot receive any additional or specific remuneration scheme.

Legalising the installation and registering it as self-consumption are the steps that allow the distribution company and your retailer to apply the compensation on your bills.

How the discount is calculated

In each billing period (usually one month):

  1. The meter records the energy you took from the grid and the energy you exported to it.
  2. The exported energy is valued at a price:
    • On the regulated PVPC tariff, the surplus price is based on the hourly electricity market price.
    • On a free-market tariff, it is the price set in your contract with the retailer.
  3. That amount is subtracted from the cost of the energy you took from the grid in the same period.

The limits you should know

Compensation has a cap: the discount can never exceed the cost of the energy you bought from the grid in that period. The energy charge can drop to zero, but it cannot go negative.

Also:

  • The capacity charge (término de potencia) and the meter rental are not discounted.
  • Surplus above that cap is neither paid nor carried over under simplified compensation. Some retailers offer their own products (so-called "virtual batteries") to use it; their terms and costs vary, so read them carefully.

Why it matters when sizing your system

The price paid for surplus energy is usually lower than the price you pay for grid electricity. So each kWh you use straight from your panels is normally worth more than one you export.

In practice, this means:

  • It is best to size the system to your real consumption, not to produce as much as possible.
  • Moving consumption to midday (washing machine, dishwasher, heat pump, EV charging) increases your savings.
  • A battery can make sense if you export a lot and use most of your energy at night. It is worth studying case by case.

How to find out how much you could save

Your savings depend on your bill, how much you use during the day, and the solar radiation where you live. Solar production in the Valencia region is high, but every case is different.

You can get a first approximate estimate with our savings calculator. For figures that fit your case, we prepare a free, written study with the recommended system size and the effect of surplus compensation on your bill.