Whether natural gas or coal is used as
the reburn fuel is a decision based largely
on economics. Factors that affect the
comparison are: (a) the cost differential
between gas and coal; (b) the capital and
operating costs of pulverizers and other
coal-handling equipment required for coal
reburning; (c) the availability of natural
gas at the site; (d) the relative impacts
of coal and gas reburning on boiler efficiency;
and (e) the possibility of generating
credits from decreased emissions of
SO2 when burning natural gas.