in the U.S.
BY SCOTT GOSSARD, BABCOCK & WILCOX
However, about five years ago, several factors converged to spur a renaissance in natural gas for power generation, and that renaissance continues
through to the present.
A combination of sustained low
natural gas prices and more stringent
environmental regulations has driven
more power providers to seriously examine natural gas as a fuel option for
energy generation. Indeed, according
to the U.S. Energy Information Administration’s 2014 Annual Energy Outlook, coal currently supplies about 41
percent of the nation’s power versus 27
percent from natural gas. But by 2035,
the agency anticipates natural gas will
be the primary fuel for electricity generation.
In particular, MATS compliance
has forced power producers to take
a hard look at the older, less efficient
coal plants in their fleets to determine
whether adding emissions control
equipment is an economical way to
bring those plants into compliance, or
whether some other option, such as
shutting them down and replacing that
capacity with highly efficient plants
that use alternative fuels like natural
gas combined cycle, makes more sense.
Besides adding costly environmen-
tal equipment or closing and replacing
coal capacity (also a costly proposi-
tion), a third avenue exists for a limited
number of utility plants. That option is
the conversion of a coal boiler to fire
natural gas – which may be significant-
ly less expensive than the other choic-
es. Fuel switching is an attractive and
economical option for utilities that
must maintain a certain generating ca-
pacity in their fleet and can’t justify the
cost of these other options.
As anyone familiar with the U.S. utility industry can tell you, the pow- er generation business is cyclical. Fuel prices,
regulations and capacity needs create
periods of peak new-build and plant
upgrade activity necessary to meet the
demands of the market.
In particular, the demand for power
generation from certain fuels is driven
by cyclical factors. Coal, natural gas, oil,
renewables and other fuels have come
in and out of vogue at different times
over the years for various reasons, usual-
ly driven by costs of a particular fuel or
regulations that tend to favor one fuel
Environmental regulations drove the
last significant wave of boiler conversions
from coal (or heavy oil) to natural gas
in the United States. In the early 1990s,
utilities and municipal plant owners in
the western states responded to more
stringent air emissions regulations imposed by state environmental agencies by
switching coal and oil plants to natural
gas. But relatively high gas prices, coupled with abundant, cheap coal resources
made more widespread coal-to-gas conversions impractical in the decade and a
half that followed.
Four coal-fired units at the Ernest
C. Gaston Electric Generating Plant
near Wilsonville, Alabama, were recently converted to burn natural gas.
Photo courtesy: Alabama Power
RETROFITS & UPGRADES Author
Scott Gossard is general manager of
Service Projects at Babcock & Wilcox
Power Generation Group, Inc.