The Tennessee Valley Authority’s board on Aug. 20 will vote on a proposal to convert the utility’s six wet-storage facilities for coal ash to dry storage. TVA’s Coal Combustion Products group, working in alliance with Stantec and URS Washington Group, drew up the proposal after last December’s catastrophic collapse of a wet-coal-ash storage facility at the utility’s Kingston Fossil Plant. Conversion will require changes in ash-handling equipment and creating storage facilities in configurations that will be decided after board approval, says Barbara Martocci, TVA spokeswoman. She would not give budget figures until after board approval. United Conveyor Corp., Waukegan, Ill., is converting Kingston’s ash-handling from wet to dry under a contract in the $50-million to $70-million range, says John Kameyer, TVA vice president. The other five plant conversions will cost less because their systems are different.