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Since 1 January 2026, the way distribution grid costs are allocated to consumers in Wallonia has changed significantly. The bihoraire — Belgium's two-rate tariff system — has been given a new schedule, and a third rate (the trihoraire) has been introduced for smart meter users.

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Why change a 40-year-old system?

The original bihoraire was introduced over 40 years ago to encourage consumption during periods when Belgian nuclear plants produced surplus electricity — mainly at night and on weekends when industrial demand was low. That logic made sense then. It no longer does today.

The distribution grid now faces fundamentally different pressures: decentralised and intermittent renewable generation (solar panels, wind turbines), and a sharp increase in power demand driven by heat pumps and electric vehicles. These patterns do not follow the old weekday/weekend divide. The new schedule is designed to better reflect when the grid is actually under stress — and to incentivise consumers to shift consumption accordingly.

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What changes for market participants

Under the old schedule, peak hours applied on weekdays only (roughly 7:00–22:00), while weekends were entirely off-peak. From January 2026, peak hours apply every day of the week — but are now limited to a tighter 7-hour window (07:00–22:00 excluding midday). The midday slot (11:00–17:00), previously peak, is now off-peak. Weekends, previously entirely off-peak, now include peak hours on the same schedule as weekdays.

For smart meter users, a new third rate — the trihoraire — is also available on request. It introduces a midday eco-rate (the cheapest), a standard rate, and a peak rate, giving consumers with flexible usage patterns a finer tool to reduce their grid costs.

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Two perspectives worth considering

The consumer signal is hard to explain

Sunday afternoon is the moment when wholesale electricity prices are typically at their lowest — solar generation is high, industrial demand is minimal, and the market is at its most relaxed. Yet under the new schedule, Sunday afternoons now fall within peak hours for distribution grid costs. The result is a mixed message to the consumer: the energy itself is cheap, but the cost of using the grid is at its highest. This is not easy to explain, and risks undermining trust in a tariff reform that is otherwise well-founded.

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A fragmented approach across regions and stakeholders

Wallonia is moving now, Brussels is targeting 2028, Flanders 2029 — each with their own methodology. While regional regulators each have their own mandate, the result is a patchwork that adds complexity for market parties operating across borders. Distribution grid costs, tariff structures, and time-of-use schedules will differ by region for years to come. One can ask whether a more coordinated approach — involving all regions, TSOs, energy suppliers, and market partners from the outset — would not have led to a more coherent and efficient outcome for everyone, including the end consumer.

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What this means in practice

The financial impact for any given customer depends on their consumption and injection pattern across the day, their region, and which tariff they are on. The new schedule affects only the proportional (variable) part of the distribution tariff, so the overall impact will vary widely.

For energy suppliers and service providers, this means updating billing systems, forecasting models, and customer communications — not just for Wallonia, but in anticipation of further changes in Brussels and Flanders in the years ahead.

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