Thread by @Arthur_Lynch_FR

🚨 It’s an honor to share my first article in Applied Energy, w/ @yannick_perez , S. Gabriel and G. Mathonnière titled « Nuclear fleet flexibility: Modeling and impacts on power systems with renewable energy » doi.org/10.1016/j.apen… #energytwitter 😇👇👇👇👇👇 🚨

Our paper focuses on two major PWR flexibility features rarely implemented in simulation models:
1) Maintenance and refueling outages schedule
2) Minimum power increases at the end of PWRs' irradiation cycles
We propose novel modeling formulation for both constraints.

1) Reactors must be shut down at regularly to carry out maintenance or refueling operations.
The placement of these outages is optimized by operators to maximize availability during peak demand.

The result is an inconstant availability of reactors depending on the season, which conditions the production capacity of the fleet, as observed, and a fortiori in recent months, in France.

2) Minimum power’s increase at the end of the irradiation cycle.
This constraint is linked to the evolution of the fuel burnup rate.

At the end of the irradiation cycle, it becomes more challenging to perform power change maneuvers due to a lower reactivity margin and a reduced boron concentration—more information in the paper.

To represent this simply, it means that the maneuvering capacity of PWRs is higher at the beginning of the irradiation cycle.
After two-thirds of the irradiation cycle, the flexibility capacity decreases linearly with fuel depletion.
The fleet's maneuverability is also modified

Our initial objective was to determine if representing these two flexibility constraints was important for modeling power systems with nuclear and renewables.

We used a simplified power system simulation model derived from French data at hourly timesteps for one year and compared different hypotheses for nuclear flexibility modeling.

➡️The first result is that representing reactors' maintenance and refueling outages schedule and minimum power evolutions is of little interest when reactors run as baseload.

In the opposite case:

1⃣ The representation of nuclear flexibility decreases estimated operational costs, renewables curtailment, flexible carbonized generating plants’ use, and, therefore, the level of CO2 emissions.

2⃣ These constraints are all the more critical to power systems simulations as the renewables penetration level is high or the size of the nuclear fleet is large.

3⃣ PWRs' flexibility reduces the occurrence of negative price hours.
The profitability of nuclear power also benefits from its ability to reduce power during high renewable production periods.

4⃣ It appears essential to consider these flexibility constraints to evaluate future power systems with nuclear power and high proportions of renewables. Modeling without these aspects may not faithfully represent nuclear flexibility capabilities.

We are currently working on extending this work, representing several zones, other generation technologies, storage technologies, and interconnections. We aim to study the interactions between nuclear and renewables further. Stay tuned for a forthcoming working paper😁!

NB : I would like to apologize for any English mistakes in this thread. I also thank the papers by @JesseJenkins et al. and @PonciroliR et al. who initiated our desire to focus on these issues. 🙏🙏🙏

Thanks for reading! 😇