For simple thermionic electricity generation, sure; this is the effect in play when the first grid gains charge with no bias applied (and a near infinite load r

For simple thermionic electricity generation, sure; this is the effect in play when the first grid gains charge with no bias applied (and a near infinite load resistance). When a positive charge is applied to the anode, the electrons do accelerate although the effect isn't comparable to a magnetron, cyclotron or linac.