# Best Energy Providers in Spain for Residents (2026) > Already have electricity or gas in Spain? Compare Iberdrola, Endesa, Naturgy, and Repsol for switching, renewal, and optimizing your existing tariff. Updated: July 2026 · By Jules · URL: https://www.how-to-spain.com/energy/providers-for-residents Updated July 2026. If you already have electricity or gas set up in Spain, this guide compares **[Iberdrola](https://www.iberdrola.es), [Endesa](https://www.endesa.es), [Naturgy](https://www.naturgy.es)**, and **[Repsol](https://www.repsol.es)** for switching, renewal, and optimizing an existing contract, rather than the first-contract setup covered on our [main providers guide](/energy/providers). ## How Do Residents Compare Iberdrola, Endesa, Naturgy, and Repsol? For an existing resident, the comparison that matters is your **current per-kWh energy price and standing charge** against each supplier's current offer for your consumption profile, not brand size. **Iberdrola** leads on renewable-tariff options, **Endesa** offers broad nationwide bundled electricity and gas, **Naturgy** remains strongest specifically for gas, and **Repsol** adds fuel-station loyalty discounts on top of its energy account. Run all four through the [CNMC](https://www.cnmc.es)'s Comparador de Ofertas de Energia using your actual annual consumption for an accurate comparison. Illustration of a lightbulb, a plug, and a home meter, for choosing an electricity and gas provider in Spain.Power, plug, and meter: energy in Spain. ## When Should Residents Switch Supplier? Switch when a competitor's per-kWh price beats yours after accounting for any early-termination penalty on your current contract, when your fixed-term contract is ending, or when you want to move from a fixed contract to the regulated PVPC tariff or vice versa. There is no cost to switch supplier itself. See our [user-review comparison](/energy/providers-comparison) for service and billing-clarity reputation, and our [price research page](/energy/providers-price-research) for illustrative bands. ## What Should You Check at Contract Renewal? At renewal, check whether your supplier has moved you onto a higher-priced default tariff, whether your **potencia contratada** (contracted power) still matches your actual usage, since an oversized contracted power wastes money on the fixed standing charge, and whether you are still eligible for or missing out on the **bono social** discount if your circumstances have changed. If a fixed-term contract includes an auto-renewal clause and you do not cancel within the notice window it specifies (commonly 30 to 60 days before expiry), the supplier can roll you onto a new contract on its own terms, sometimes at a materially higher price, and suppliers are required to notify any price revision at least 30 days in advance; consumer groups recommend reviewing your contract 60 to 90 days before renewal to compare offers and avoid an unfavourable automatic rollover (source: OCU and consumer energy guidance, as of July 2026). Illustration of a lightbulb, a plug, and a home meter, for choosing an electricity and gas provider in Spain.Power, plug, and meter: energy in Spain. ## Related Guides [### Energy Providers: User Reviews Sentiment scores for every supplier.](/energy/providers-comparison)[### Electricity & Gas for Residents PVPC vs fixed, bono social, and switching.](/energy/electricity-gas-for-residents) ## Frequently Asked Questions ### Which energy provider should residents switch to for the best price? There is no single answer, since Iberdrola, Endesa, Naturgy, and Repsol reprice frequently and the best offer depends on your consumption profile, contracted power, and whether you want green sourcing or bundled gas. Run your current per-kWh price through the CNMC's Comparador de Ofertas de Energia against current offers from all four before switching, and see our user-review comparison for reputation on service and billing clarity. ### Is it worth switching suppliers if I am still under contract? Check your existing contract for an early-termination penalty clause (clausula de permanencia) first. Many free-market contracts in Spain, including standard offers from Iberdrola, Endesa, Naturgy, and Repsol, allow switching without a fee, but fixed-term promotional offers can include a penalty. By law, any such penalty on a low-voltage household contract is capped at 5% of the remaining energy cost owed under the contract, so even a worst-case penalty is usually modest compared to what a cheaper tariff saves over a year (source: Real Decreto 88/2026, in force since 12 February 2026, as of July 2026). ### Do Iberdrola, Endesa, Naturgy, or Repsol offer loyalty discounts for long-term customers? Yes. Repsol's Waylet app credits fuel-station discounts to customers who also hold its electricity, gas, or solar contracts, up to around 20-25 cents per litre in combined promotional savings depending on which Repsol products a household holds, plus its Waylet card adds a 2% cashback on electricity and gas bills; check the current terms directly on Repsol's site since promotional fuel discounts change frequently (source: Repsol, repsol.com and repsol.es, as of July 2026). --- Source: https://www.how-to-spain.com/energy/providers-for-residents Last updated: Updated: July 2026 Format: LLM-readable Markdown twin (.md) of the canonical HTML page.