Brightcon 2025, hackathon & courses in Grenoble and online

Highlights:

1. CAIRN (CairnOpen) demo from CEA: brief demonstration of core
   capabilities, modular technology components, scenario management,
   MILP constraints for sizing/operation, multiple solver back-ends,
   time-series I/O, and reproducible exports.
2. BW2 to CAIRN integration via GUI: a graphical interface links
   Brightway2/Activity Browser activities to CAIRN, enabling direct
   import of foreground systems into the MILP model without custom glue
   code.
3. Hybrid GA+MILP for explicit trade-offs: a genetic algorithm explores
   system configurations while CAIRN’s MILP computes per-individual
   optima; Pareto dominance and hypervolume metrics reveal and
   stabilize the non-dominated frontier.

Short proposal:

Designing sustainable energy systems requires methods that address environmental impacts, economic costs, and technology evolution. We present a hybrid multi-objective framework that couples prospective life-cycle inventories with deterministic and evolutionary optimization, applied to a green hydrogen supply chain in Mallorca (GreenHysland, 2025). The workflow integrates: (i) premise to adapt ecoinvent under forward-looking European energy scenarios; (ii) Brightway2 to compute impacts under EF 3.1 midpoint (16 categories); and (iii) CAIRN, an open-source engine that solves mixed-integer linear programs (MILP) for component sizing and operation.

Three implementation advances are central. First, a graphical interface connects Brightway2 (and Activity Browser) with CAIRN, importing previously defined activities and foreground systems as parameterized components that can be optimized directly, improving transparency and reusability.

Second, the ENTSO-E API provides hourly electricity mixes from which hourly impact factors are derived; these time-resolved factors are injected into the MILP, yielding dispatch and sizing decisions consistent with real grid variability rather than average values.

Third, the optimization is hybrid, a genetic algorithm generates a population of candidate configurations. For each individual, CAIRN’s MILP computes the cost/impact-optimal system, the GA evaluates Pareto dominance and evolves toward a robust non-dominated frontier.

The study assesses portfolios combining PV generation, electrolyzers, storage, and hydrogen distribution (trucks versus pipelines), including partial substitution in public transport. Results show meaningful trade-offs across categories: designs minimizing GHGs can increase mineral resource use. The workflow, and github of CAIRN will be shared to facilitate reuse across regions, scenarios, and impact methods.