  A method for computing the thermopower in interacting systems is proposed.
This approach, which relies on Monte Carlo simulations, is illustrated first
for a diatomic chain of hard-point elastically colliding particles and then in
the case of a one-dimensional gas with (screened) Coulomb interparticle
interaction. Numerical simulations up to $N>10^4$ particles confirm the general
theoretical arguments for momentum-conserving systems and show that the
thermoelectric figure of merit increases linearly with the system size.
