This paper discusses the results of EPA's tests of five electrostatic collection concepts over the last 4 years: electric curtain, electrostatic scrubbing, electrostatic fiber beds, charged droplet scrubbing, and electrostatic effects on fabric filters. Of the five, electrostatic scrubbing and those concepts using filters prove to be the best collection methods. Electrostatic scrubbing efficiency depends on the presence of an ambient electric field and the charge of the droplets. Charged droplets in an ambient electric field use only a minimal amount of energy and are more efficient at 0.5 and 1.0 micrometers. Collection efficiency with fabric or fiber filters depends on the medium: precharging enhances the performance of fiber filters, making them more efficient than fabric filters. The electric curtain collection method is efficient at low velocities, but for fly ash collection under stack conditions, this method is not effective.