In this paper we write the 0-D energy balance in terms of the parameters , and . The minimum value of W required to achieve ohmic ignition (i.e. II = 0) in the generic case (i.e. no n or T dependance on τ), and for various dependencies of τ on n and T is W ∼ 15 in all cases. Also the value of W below which no access, even with the aid of auxiliary power, to high temperature alpha dominated operation is possible is W ∼ 2 in all cases. Optimized designs are obtained by minimizing the ratio of the auxiliary power pa to the ohmic power pΩ at the Cordey pass. The optimization is consistent with the physics requirements, the toroidal field coil volume and stress constraints, and with the volt-second and stress constraints of the ohmic transformer. Results under various τ dependencies are presented.