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Role of nuclear extension and restart in the energy system

In the course of 2023, Febeliec commissioned EnergyVille to calculate sensitivity scenarios to analyse the impact of increasing the extension of the lifetime of the nuclear power plants in two ways:

- What if the Doel 4 and Tihange 3 nuclear power plants would be operational until 2045 instead of 2035?
- What if the lifetime of two additional nuclear power plants would be extended?

The model setup and parameters relied on to calculate these sensitivity scenarios are identical to those of the PATHS2050 study, in which the parameters related to nuclear power plants were updated. The new sensitivity runs are based on the ‘Electrification scenario’ of the PATHS2050 study, where we allowed investments in 16 GW additional offshore wind imported from the far North Sea to Belgium from 2030 onwards, and Small Nuclear Reactors operational from 2045 onwards.

Important to note is that this most recent study looks at the potential economic benefits and costs of nuclear extension from the energy system point of view. In other words, the study sheds light on what the maximum cost per unit of electricity produced can be to make a lifetime extension cost-effective in the energy system. This study does not assess the investment business case for a nuclear extension.

Furthermore, it is to be noted that all numbers regarding costs in this study are in €2019, in accordance with our other PATHS2050 results.

##### Summary

**Note 1**:**Estimated costs for nuclear extension projects in Doel 4, Tihange 3, and other Belgian plants were not available.**

Therefore, in this study, it is assumed that the total cost of expanding the nuclear power plants is equal to the strike price for nuclear energy, ranging from 65€/MWh to 75€/MWh. This study does not provide information on the bottom-up costs of extending the operational lifespan or restarting nuclear power plants.

**Conclusion 1: Extending Doel 4 and Tihange 3 by 20 years at a total cost of 65€/MWh would be cost-effective.**

A scenario was examined in which 65€/MWh was considered to be the total costs of extending nuclear energy over 20 years. The results indicated that this extension is part of a cost-optimal mix.

**Conclusion 2: Restarting an additional 2 GW of nuclear power plants in 2030 for 20 years is only cost-effective if the cost is less than 75€/MWh.**

The question examined was the following: if Doel 4 and Tihange 3 are extended for the period 2025 - 2045, what would be the impact of restarting an additional 2 GW of nuclear power plants, namely Doel 3 and Tihange 2, from 2030 to 2050? A sensitivity analysis indicated that this investment could be cost-effective under a price of up to 75€/MWh. This is an upper limit, meaning that an investment above 75€/MWh would not be cost-effective. The costs for restarting this additional 2 GW will certainly be higher than for the already planned restart of Doel 4 and Tihange 3, as Doel 3 and Tihange 2 have been closed in the meantime. Costs for grid extensions were not included in this calculation.

**Conclusion 3: The cost-effectiveness of restarting an additional 2 GW of nuclear power plants decreases over time.**

Currently, no public information is available from the operators regarding the operational extension of nuclear power plants other than Doel 4 and Tihange 3. Therefore, preparing Doel 3 and Tihange 2 for energy production by 2030 comes with a significant amount of uncertainty and challenges. Given the many obstacles still in place to restart nuclear power plants currently being prepared for decommissioning, a sensitivity analysis was performed, assuming that technical updates or investments for a restart would only be ready by 2035 instead of 2030. In that case, the threshold for a cost-effective investment would be 70€/MWh instead of 75€/MWh. The reason for this is that in the next decade, a substantial amount of electricity will still be produced from gas, while towards 2050, more and more electricity will be produced from cheaper renewable energy sources, reducing the profitability margin for extending the operational lifespan of nuclear power plants.

**Conclusion 4: Extending Doel 4 and Tihange 3 by 20 years results in lower investments in renewable energy; the restart of Doel 3 and Tihange 2 reinforces this effect.**

Significant amounts of renewable energy sources would be replaced by nuclear energy when 4 GW of nuclear energy is extended by 20 years. In 2030, for one terawatt-hour (TWh) of nuclear energy (13.5 TWh in total annually, assuming 80% availability), only 0.1 TWh of renewable energy would be displaced by nuclear energy. By 2040, the first 2 GW of nuclear capacity would already replace 0.6 TWh of renewable energy; however, the second 2 GW would replace 0.8 TWh of renewable energy per terawatt-hour of nuclear energy. Thus, the 20-year extension/restart of nuclear energy also has a negative impact on the investment certainty/profitability of renewable energy sources.

**Conclusion 5: Restarting an additional 2 GW of nuclear power plants, in the shape and form of Doel 3 and Tihange 2, and extending Doel 4 and Tihange 3 by 20 years, have an impact on the energy system and reduces emissions, but they do not fundamentally change the emission reduction pathways.**

When extending 4 GW of nuclear power plants, there is a CO_{2} emission reduction of 2.1 Mt/year in 2030 and 1.8 Mt/year in 2040. The CO_{2} emission reduction by adding the first 2 GW – by extending Doel 4 and Tihange 3 – and the last 2 GW – by restarting Doel 3 and Tihange 2 – is 1.2 Mt/year and 0.6 Mt/year respectively in 2040. Extending 2 GW of nuclear energy until 2050 does not significantly increase the share of nuclear energy in that year; the model keeps the share of nuclear energy production relatively constant at 20% of the total production, while investments in new nuclear energy are postponed. Expanding the number of nuclear power plants extended for twenty years could hinder investments in small modular nuclear reactors.

**Note 2: This study evaluates nuclear extension from an energy system perspective, not its business case.**

It is important to note that this follow-up study examines the potential economic costs and benefits of nuclear extension from the perspective of the energy system. In other words, the study provides insight into whether a 20-year extension of 2 GW (Doel 4 and Tihange 3) is cost-effective. Additionally, the study sheds light on at what electricity production cost an extension of 2 GW of additional capacity (Doel 3 and Tihange 2) could be cost-effective for the energy system. This study does not assess the business case for investments in nuclear extension or restart. Therefore, it does not provide additional information about the practical feasibility and the possibility of finding an operator willing to finance the investments in the restart of nuclear power plants.

##### Download the follow-up report

You can find a detailed description of the scenarios, the assumptions used for these additional sensitivities and the results in this report.