Tarifas eléctricas para empresas en España: cómo funcionan la 3.0TD y la 6.1TD
Since 2021, Spanish companies have been operating under an electricity tariff system that completely changed the way electricity bills are calculated. That reform, driven by Circular 3/2020 of the National Markets and Competition Commission (CNMC), remains the foundation of the tariff system today, although toll and charge prices are reviewed every year. Understanding how it works continues to be key for any company wishing to control its energy expenditure.
In essence, an electricity tariff is the price structure applied to a business's consumption and contracted power. It is not just about how much energy you use, but when you use it and how much power you have contracted at any given time of the day. Since the 2021 reform, the variable component of the bill carries much more weight than before, meaning that two companies with the exact same total consumption can end up paying very different amounts depending on how they distribute that consumption throughout the day and year.
The reform replaced the old 3.0A tariff with the 3.0TD, applicable to low-voltage consumers with a contracted power of over 15 kW (the vast majority of SMEs, offices, shops, and premises). The most significant change was moving from a system of three time periods (off-peak, mid-peak, and peak) to a six-period system, for both energy and power. For large high-voltage consumers with power exceeding 451 kW, the old 3.1A tariff became the 6.1TD, also maintaining the six-period scheme.
In practice, this means that the price of electricity varies depending on the period of the day, the month of the year, and the geographical area (mainland, Balearic Islands, or Canary Islands), ranging from P1 (the most expensive) to P6 (the cheapest). The exact intervals and months can vary with regulatory revisions, so it is advisable to check the current calendar of periods each year, available on the CNMC website or through your supplier, rather than relying on an outdated table.
Another element that continues to shape any company's bill is the escalating power rule. The regulations require that the contracted power in each period must be equal to or higher than that of the previous period, following the rule P1 ≤ P2 ≤ P3 ≤ P4 ≤ P5 ≤ P6. If a company does not review and renegotiate its power capacities per period after the system change, it often ends up with much higher power than actually needed in several intervals, resulting in avoidable extra costs. It is worth remembering that contracted power can only be modified for free once a year, so it pays to study each case carefully before changing any numbers.
Penalties for exceeding contracted power also changed with the reform and continue to apply today. Companies with contracted power between 15 and 50 kW (small businesses, offices, homeowner associations) maintain the maximeter penalty system. However, those with between 50 and 450 kW (hotels, shopping centers, universities, medium-sized industrial units) transitioned to a fifteen-minute interval penalty system, just like high-voltage consumers: consumption is measured every fifteen minutes, and if the average for that quarter-hour exceeds the contracted power for that period, the corresponding penalty is applied. This system, combined with a good energy monitoring system, allows for precise detection of when contracted power is being exceeded so action can be taken before it results in extra costs.
Inductive reactive energy also continues to be penalized when it exceeds 33% of the active energy consumed, and this penalty applies in periods P1 to P5. This is an aspect that many companies overlook and which can be corrected with relatively simple reactive power compensation equipment.
An important point for 2026: access tolls to the transmission and distribution networks, as well as the charges added to the bill, are updated annually through a CNMC resolution and ministerial order. For this year, the values in force since January 1, 2026, were set by the CNMC Resolution of December 18, 2025 (BOE-A-2025-26348) regarding tolls, and by Order TED/1524/2025 regarding charges. This means that, although the structure of periods and the escalating power rule remain stable, the specific prices for each period change every year, making it advisable to check the current resolution before making decisions on contracted power.
Beyond the regulatory aspects, there are common-sense measures that help any business reduce its electricity bill: making the most of natural light instead of unnecessarily turning on artificial lighting, investing in good thermal insulation for the premises (the savings on heating and cooling later will more than offset the initial investment), controlling air conditioning and heating with timers to prevent them being left on by mistake, and completely disconnecting standby equipment, which continues to consume power even when it appears to be switched off.
Knowing how much and when your business consumes is the first step toward making informed decisions about contracted power and tariff periods. Having a platform that monitors consumption in real-time, detects anomalies, and helps anticipate energy behavior before it is reflected in the bill makes the difference between suffering from the tariff reform and using it to your advantage. If you want to better understand how your business's consumption behaves before renegotiating power capacities, speaking with an energy management specialist is a great starting point.