To analyze the energy balance, the range of optimal parameters of the quasistationary burn phase of p-11B plasma is assessed under conditions of fuel refill and external energy supply. The reaction rate parameter is determined considering the difference in the macroscopic velocities of the fuel components. An increase in the corresponding relative energy from 0 to 100 keV leads to an increase in the plasma power gain Q by a factor of 3. Regimes with Q ≈ 5 correspond to npτ ~ 1021 m–3s, where np is the proton density and τ is the confinement time. These conditions are close to optimum from the point of view of the fuel burnout rate, energy transfer to plasma from the generated high-energy alpha particles, and bremsstrahlung losses associated with their accumulation in the plasma. Also, to assess the influence of the content of alpha particles, a mode with a reduced confinement time of alpha particles is considered. In such a mode Q > 5 can be achieved.