Virtual battery (batería virtual) at Naturgy and Endesa explained

As of 11/2026 · Solemo

With a solar system you often produce more in summer than compensation can offset. A virtual battery stores this remainder as euro credit. That sounds good – whether it pays off depends on the details.

Without a virtual battery: compensación simplificada

Per billing period (max. 1 month): value of grid energy minus value of surplus, result at least EUR 0. Only the energy term falls; power charge, meter rental and bono social financing remain. Anything not offset is lost every month. A bill of EUR 0 is not possible this way because fixed costs remain.

With a virtual battery

The batería virtual is not a law but a supplier product. The remainder that cannot be offset is stored as euro credit and later deducted from the bill total – depending on the supplier also from power, taxes, gas or other supply points. With large surpluses the bill can drop to about EUR 0.

For tax purposes, credit from earlier months does not reduce the tax base (Dirección General de Tributos, V1146-24) – it is only a means of payment. Energy offset by compensation in the same month, however, is exempt from electricity tax.

Naturgy and Endesa compared (as of 1 Nov 2026)

	Naturgy Batería Virtual	Endesa Solar Plus & Batería Virtual
Fee	EUR 0/month	EUR 2/month
Surplus credit	EUR 0.06/kWh (revisable monthly)	EUR 0.06/kWh
Credit usable	5 years; for all Naturgy bills of the same holder, including other supply point numbers (CUPS)	same supply point number (CUPS) only – per secondary sources
Electricity price (excl. taxes)	depends on the chosen 2.0TD tariff with compensation	EUR 0.1649/kWh; power EUR 0.093666/kW·day (as of 15 Oct 2026) plus EUR 0.024688/day

Other offers our calculator lists for information only: Repsol (EUR 1.99/month, EUR 0.06/kWh, partly secondary source), Iberdrola Solar Cloud and Octopus Solar Wallet (secondary sources only). We show which tariffs are cheapest for you.

What to watch out for

Energy price of the solar tariff: a higher electricity price can eat up the benefit. Compare the annual total, not just the credit rate.
Credit piling up: if the system is large relative to consumption, credit accumulates and can expire (Naturgy after 5 years). The value per exported kWh then falls.
Monthly fee: with small surpluses a fee can exceed the benefit.
Several supply points: if you have e.g. a house and a flat with the same supplier, it helps when credit also applies to other CUPS.

How our calculator handles it

For houses with their own roof the calculator works out the annual bill month by month for each option (PVPC with compensation, Naturgy, Endesa): bill without and with PV, savings, months at ~EUR 0, lowest monthly bill and unused credit. All figures are estimates.

This article summarises public sources (as of 11/2026). Rules and prices change – check the linked original sources before deciding.

Check your own bill

The calculator explains your bill line by line and works with your own figures.

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