13 March 2025
Belgium’s energy strategy is evolving, with major shifts in nuclear policy. The latest decisions on nuclear of the Arizona government led by Prime Minister Bart De Wever could significantly reshape the country’s energy transition, bringing both challenges and opportunities.
Nuclear phase-out… or not ?
- The government plans to extend the lifespans of the Doel 4 and Tihange 3 reactors until 2045—adding another 10 years beyond the previously agreed extension with Engie.
- A major policy shift: the nuclear phase-out law will be revoked, allowing for the lifetime extension of all existing reactors (4 GW).
- Doubling nuclear capacity? Energy Minister Mathieu Bihet announced on the 4th of February 2025, plans to increase nuclear power capacity from 4 GW to 8 GW, combining new reactor construction with lifetime extensions.
What does it mean for the electricity mix ?
Clear signals were needed for electricity security
Belgium’s grid operator Elia has emphasized the need for long-term clarity on power generation in its recent Blueprint study for 2035-2050. Extending reactors requires major investment with long lead times, while renewables and flexibility solutions (storage, demand-side response) need a stable policy framework to scale up.
Nuclear alone won’t be enough
If those announcements bring clarity to the energy sector, betting on nuclear alone won’t be sufficient to meet rising electricity demand in the short-term, warns Elia. The 60TWh electricity generation deficit which had been identified in 2036 could be reduced by extending the lifetime of existing nuclear units and by building new ones as announced by the government. Though, a 30TWh gap would remain which will ask for additional measures like:
- Getting access to non-domestic offshore, yielding a potential of 15TWh of generation by 2036. This lever was found to be the most cost-effective and resilient solution by Elia in their study;
- Increasing the installation rate of domestic renewables, yielding a potential of 9TWh of generation by 2036. This increase would be additional to the installation rate need to reach Belgium’s NECP and would require drastic efforts, as the onshore wind installation rate should be doubled while solar PV installation rate should increase by four. For example, in Wallonia, onshore wind and solar PV capacities have to double in the five upcoming years to meet the 2030 regional target;
- Leveraging energy sufficiency measures, yielding a potential of 18TWh of reduction of the demand by 2036. About 10TWh could be obtained by playing on behavioral levers: 5TWh of which could- be obtained with low efforts measures (by decreasing the temperature set point for example, as during the energy crisis), while other 5TWh would require longer-term change, like reducing the average size of cars and average size of dwellings.
- Extending the lifetime of gas-fired generators could yield a potential of 15-30TWh of generation. However, the energy produced would not necessarily be carbon neutral, putting at risk Belgium’s climate goals.
What about the rest of our energy mix ?
The decarbonization of electricity in Belgium is a key challenge as it raises questions on both Belgium’s means to reach its carbon neutrality by 2050 and energy security strategies, ensuring lights are kept on all year-long.
Yet, Belgium’s energy transition is a challenge extending far beyond electricity. In fact, electricity only represented 18% of the final demand in 2023, with most of the final energy consumed today in Belgium coming from oil products (48% of final energy demand) and natural gas (25% of final energy demand, on top of which natural gas for electricity generation must be added) as shown by Statbel.
This underlines the fact that the energy transition requires a systemic, science-based approach—not just isolated decisions— and that looking at the big picture is crucial.
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At Climact, we help organizations design and explore robust transition scenarios using our Pathways Explorer, while analyzing energy system impacts with PyPSA-Eur, an open-source modeling tool.
So if you are:
- Assessing how evolving policies could impact your organization’s energy strategy,
- Curious about which energy investments are most aligned with your climate objectives,
- Interested in modeling the resilience of your energy system against future uncertainties or
- Looking to understand the role of renewables, nuclear, or hydrogen in your decarbonization roadmap or
- Wondering how much flexibility capacities and infrastructure reinforcements are needed for the energy transition?
Start exploring relevant decarbonation scenarios for your organization here : www.pathwaysexplorer.org
Sources
Belgian electricity system blueprint for 2035-2050 by Elia Group – Issuu
https://economie.fgov.be/fr/publications/belgian-energy-data-overview-2