  We calculate thermopower of clean and impure bilayer graphene systems.
Opening a band gap through the application of an external electric field is
shown to greatly enhance the thermopower of bilayer graphene, which is more
than four times that of the monolayer graphene and gapless bilayer graphene at
room temperature. The effect of scattering by dilute charged impurities is
discussed in terms of the self-consistent Born approximation. Temperature
dependence of the thermopower is also analyzed.
