Power start-up for Mochovce 4

Slovakia's Mochovce 4 achieved initial power generation on Monday, the operator Slovenske elektrárne announced. The unit is now in the final stages before commercial operation. Mochovce 4 is a 471 MW pressurised water reactor that has been under construction for decades.

Where this fits

Mochovce 4 is a data point in the firm-power story. It adds a unit of dispatchable, low-carbon generation to the European grid without material dependency on China, weather variability, or the need for fossil-fuel backup to manage renewable intermittency. Slovakia is not choosing between renewables and nuclear; it is completing a nuclear build that runs alongside its renewable capacity and reduces reliance on fuel imports. The contrast with Australia's legal ban on nuclear generation is stark: while Europe locks in firm capacity with minimal lifecycle emissions, Australia is betting the grid's reliability on weather-dependent sources and the backup gas plants required to manage them.

What it means

Australia's energy security rests on the assumption that weather-dependent renewables plus battery storage plus gas firming will deliver reliability at lower whole-system cost than a mix that includes firm nuclear generation. Mochovce 4 entering service is evidence that the nuclear alternative is real, deployable, and adds to grid resilience without creating strategic dependency on China for supply-chain continuity. Australia's choice to close Liddell and Eraring, and to ban new nuclear builds, forecloses the low-emission firm-power option that Slovakia is exercising. The renewables-only path is increasingly a choice made by law, not by economics or energy security.