In an up-and-coming podcast, I will be discussing the controversy surrounding the Charter Street Heating Plant with a guy who knows a little more about energy policy than I do. But until then, I will point you to one interesting fact: Biomass may be less environmentally beneficial than natural gas, which is the other option that the plant is pursuing.
In fact, the comprehensive study of the plant gave the biomass boiler a lower environmental score than an upgraded gas/oil boiler. The latter also received a better economic score.
Of course, the score for the gas boiler is based largely on...you guessed it...the price of gas. When designing a system that is supposed to last decades, the current price of a commodity as volatile as petroleum is barely a a relevant indicator of overall costs. And who knows how much biomass will cost decades from now? It largely depends on whether or not states invest in it.
Here's another problem a biomass boiler could face: The wood chips it burns may already contain mercury from other industrial emissions.