Bloom Energy makes fuel cells that can run on natural gas. This site would need a very large number of them to replace gas generators. Each "bloom box" can create 325kW and are about 1m x 1m x 2m in size.
They make sort of whine/squeal noise when operating. Not sure of the dB level.
San Jose Ice Rink has had a bunch of these installed out back for about 10 years I think.