The commission and Mirant disagreed on how big steam plumes from the plant's cooling towers would be and how noticeable they would be to the surrounding area. A committee assigned to the project will make a recommendation Monday, and the full commission is expected to vote soon after. And indeed, the biggest point of contention to appear over the course of the applications was resolved last month when Mirant agreed to move the planned unit away from the Sportsmen Yacht Club's ferryboat clubhouse. But the commission staff and Mirant were sharply divided on the effects of the plumes that form when the air from the towers is released into the atmosphere and the moisture in it condenses.
Plumes are most prevalent on clear days in winter.
As a condition of approval, the commission recommends in its final staff assessment that Mirant's cooling technology limit plumes to certain sizes and frequencies depending on the time of year. One question is whether Mirant can meet those expectations with the wet cooling system it intends to use. But Mirant representatives challenged the commission's standards, the analysis on which they were based, and the wisdom of changing cooling technologies so late in the game. Valerie Zambito, Mirant's director of engineering, said hybrid and dry-cooling systems may produce smaller plumes but they also reduce energy output, and increase fuel use, pollution output, time and cost. Toward the end of the hearing, Tony Chapman, representing Sportsmen Yacht Club, implored the commission to resist political pressure to speed up approval of new power plants amid the state's energy crisis.