The study examines how nuclear power plants fit into energy systems with lots of renewable energy, like wind and solar. Researchers looked at how keeping Spanish nuclear plants running for a long time affected costs, profits for nuclear companies, and decisions about building new power sources. They also checked if flexible nuclear plant operations could help. Results show that running nuclear plants longer cuts down on carbon dioxide emissions from making electricity. But we still need more clean energy sources and storage to meet high renewable energy goals. This could mean less money for nuclear companies.