This paper examines the economics of magnetic fusion power generation, makes comparisons with other generation sources, and draws attention to some key issues. For other generation sources, the data presented are drawn from published references, but specific studies have been made for magnetic confinement systems. The magnetic fusion costs are benchmarked by comparison with those for ITER, since considerable effort has been invested in establishing the validity of the ITER costs.

Estimated fusion generating costs are broadly comparable with fission and fossil fuel costs, and with the more promising of the renewables (not taking into account external cost factors and public acceptability issues). These external factors make it impossible to determine which generating source will be the most attractive in the mid-21st century, and may even preclude the use of some sources, making it strategically important to develop a range of options. Key factors in determining which energy sources are adopted in the 21st century are likely to be environmental and safety attributes.

For the main magnetic fusion concepts under study in the world fusion programme the costs of electricity generation are similar when equivalent levels of physics and technology performance are assumed. The tokamak is the most developed concept. Other approaches have potential intrinsic physics or technology advantages over the conventional tokamak, that are yet to be fully demonstrated.

Only very minor constraints on economic optimisation of designs are entailed by the requirement to preserve, during the optimisation, the full safety and environmental advantages of fusion.

The overall conclusion is that the likely economic performance of fusion, combined with its excellent safety and environmental qualities, as shown in the SEAFP (Safety and Environmental Assessment of Fusion Power) study, make it a serious contender as one of the few major contributors to mid-21st century electricity generation.