Washing machines are not simply tied to nighttime usage as a guaranteed saving. A year after the government and the National Markets and Competition Commission (CNMC) reshaped how electricity is billed by splitting the price into time slots, many households have adapted their routines. The Iberian mechanism, which parties hoped would make nighttime consumption cheaper, remains a volatile feature that can change quickly. The night period can turn into one of the most expensive windows of the day, and the cheaper hours often shift in the late afternoon, typically from 15:00 to 17:00, while the late evening between 21:00 and 22:00 can be costly as well.
The rationale behind this adjustment is to balance the gas price cap in the electricity market. When demand drops, the compensatory costs for the gas-plant generation rise, especially in the hours when daytime consumption is lower. The managing director of Ecological Transition for the Community of Valencia, Rubén Fresco, notes that at night there is little solar energy and, depending on wind conditions, fossil fuel generation can form a large share of output. That compensation, while small per household, can be substantial overall.
Anyone can glance at the daily charts published by OMIE, the Iberian market operator, to grasp the impact. Prices tend to peak in the early morning hours, around 4 to 6 a.m., and dip again later in the day, often around 15:00 to 17:00. This happens because the afternoon sees higher demand, which spreads the compensation over more users, and the afternoon also benefits from higher solar production, reducing the reliance on fossil fuels.
There are days when the pattern shifts. Wind availability is a key factor since nighttime generation relies less on sun. Summer, however, is not typically windy, unless storms arise, so night rates tend to stay high for stretches. The autumn could bring changes as wind power reaches full capacity, potentially lowering the compensation. Fresco adds that summer is not ideal for the current mechanism, but the system generally behaves more predictably as months pass.
The price paid by a consumer under PVPC, a regulated tariff, depends on three main elements: the daily market price, which is usually cheaper at night; the tolls and fees that are higher during the day; and the compensation paid to gas-plant plants, which accounts for the difference between the cap and actual costs and tends to be higher during the day and night as needed.
The outcome of this equation hinges on the day’s fossil fuel output, the gas price, and how many consumers are affected by the gas compensation adjustment. On a day like today, it can be cheaper to run a washing machine between 10:00 and 13:00, rather than during the early-morning valley from 03:00 to 08:00. Fresco observes that there will be fewer 3 a.m. washes in favor of a 3 p.m. slot.
A year of changes
Two years elapsed for the government and CNMC to implement a mechanism that defined three time slots: peak hours from 10:00 to 14:00 and 18:00 to 22:00; straight time from 08:00 to 10:00, 14:00 to 18:00, and 22:00 to 00:00; and valley from 00:00 to 08:00, with holidays and weekends treated separately. The debate centered on how consumption patterns drive costs, and the aim was to nudge consumer behavior to ease the load on the grid.
The timing coincided with a rise in natural gas prices following reduced imports from Russia, a combination that prompted temporary policy pauses from June to September. On September 14, the Ministry of Ecological Transition announced measures to lower electricity bills, including a substantial cut in billing fees by about 96 percent, which intended to limit price differentials. The effect was to curb outages and narrow hourly gaps, keeping night rates the cheapest option for households.
By January, the discount was reduced to about 30.9 percent of the fares, and the most favorable times shifted as the solar energy mix grew. The early afternoon period, once less competitive, began to attract more cost considerations as new solar capacity came online. Today, the Iberian mechanism continues to evolve, and the night remains the cheapest window, though its advantage varies with wind, sun, and gas dynamics, causing the price story to move through the season.