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 a
re drawn from published references, but specific studies have been mad
e for magnetic confinement systems. The magnetic fusion costs are benc
hmarked by comparison with those for ITER, since considerable effort h
as been invested in establishing the validity of the ITER costs. Estim
ated fusion generating costs are broadly comparable with fission and f
ossil fuel costs, and with the more promising of the renewables (not t
aking into account external cost factors and public acceptability issu
es). These external factors make it impossible to determine which gene
rating source will be the most attractive in the mid-21st century, and
may even preclude the use of some sources, making it strategically im
portant to develop a range of options. Key factors in determining whic
h energy sources are adopted in the 21st century are likely to be envi
ronmental and safety attributes. For the main magnetic fusion concepts
under study in the world fusion programme the costs of electricity ge
neration are similar when equivalent levels of physics and technology
performance are assumed. The tokamak is the most developed concept. Ot
her approaches have potential intrinsic physics or technology advantag
es over the conventional tokamak, that are yet to be fully demonstrate
d. 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 concl
usion is that the likely economic performance of fusion, combined with
its excellent safety and environmental qualities, as shown in the SEA
FP (Safety and Environmental Assessment of Fusion Power) study, make i
t a serious contender as one of the few major contributors to mid-21st
century electricity generation.