  Fusion could be a part of future decarbonized electricity systems, but it
will need to compete with other technologies. In particular, pulsed tokamak
plants have a unique operational mode, and evaluating which characteristics
make them economically competitive can help select between design pathways.
Using a capacity expansion and operations model, we determined cost thresholds
for pulsed tokamaks to reach a range of penetration levels in a future
decarbonized US Eastern Interconnection. The required capital cost to reach a
fusion capacity of 100 GW varied from \$3000/kW to \$7200/kW, and the
equilibrium penetration increases rapidly with decreasing cost. The value per
unit power capacity depends on the variable operational cost and on the cost of
its competition, particularly fission, much more than on the pulse cycle
parameters. These findings can therefore provide initial cost targets for
fusion more generally in the United States.
