Fusion research lives with the witticism: "Fusion is the energy of the future and always will be". The task is so complex with so many unsolved problems that there must be doubt that an economy based fusion power plants will ever come into existence, nevertheless many plans are in place for the path towards this. 

Although ITER is an project of international cooperation, for the future there will be numerous national or continental towards commercial fusion power. The scheme below indicates a progression from ITER to Power Plant featured in US plans. In this schedule pass through the step of a Fusion Nuclear Science Facility. EU plans move directly from ITER to DEMO and so imagines moving faster. Dates in various plans are presented below.

European Plans towards a prototype Fusion Plant

The timeline below show the European fusion plans for a DEMO plant which would generate 500MW of electricity. The timeline of DEMO is dependent on the success of 6 milestones from ITER. A particularly essential milestone is the validation of the Tritium Breeder Module of which there is considerable doubt, with some experts predicting that ITER will not provide an adequate demonstration of the complex systems required to re-cycle tritium in a real reactor.

Chinese Plans towards a Fusion Power Plant

Several countries have independent plans for a prototype reactor based on the TER program and design basics. The Chinese plans are illustrated below and show after ITER, a first prototype reactor of, 200 MW, further validating certain systems, followed by a 1 GW reactor. Even with this extra step the timescale indicated is similar to that of Europe.

US Plans towards a Fusion Power Plant

In the US many scientists and engineers consider an extra R&D facility, FNSF, is required between ITER and a DEMO fusion reactor prototype. Neither this facility or the US DEMO is funded as yet.

Introducing such a further step in the schedule clearly would delay the DEMO reactor by decades.

Realism ?

The plans above for Europe and for China project operational devices around 2050, but already ITER is late compared to these plans. As discussed, there is an enormous challenge to make a tritium breeder system and the US considers the FNSF is necessary step before launching construction of the US DEMO. This would put a prototype fusion towards 2080. With so many uncertainties, no schedule can be considered reliable more than 50 years in the future.