The energy dissipation in a proposed digital device in which discrete degrees of freedom are used to represent digital information (a "single-electron parametron") was analyzed. If the switching speed is not too high, the device may operate reversibly (adiabatically), and the energy dissipation E per bit may be much less than the thermal energy scale k(B)T (where k(B) is Boltzmann’s constant and T is temperature). The energy-time E(tau) is, however, much greater than Planck’s constant HBAR, at least in the standard "orthodox" model of single-electron tunneling that was used in these calculations.