POWER April 2016 - 69

ENVIRONMENTAL REGULATION
4. Below the threshold. Monitored SO2 data for 2015 did not exceed the 75 ppb threshold.
Courtesy: Alliant Energy
80
70
60
50
40
30
20
10
was detecting.
Designations of nonattainment with air
quality standards require agencies with
responsibility for air quality, such as the
LCPHD and the IDNR, to develop programs
intended to reduce pollutant levels and
manage permits for new emissions source
development so the predicted pollutant concentrations
do not intensify.
Early action and transparent discussions
led to a better understanding of the circumstances
the area was facing. That communication
helped to develop action plans to monitor
the issue and prevent reoccurrence of monitored
SO2
levels in excess of the 1-hour SO2
standard. Proactively working with officials,
especially the LCPHD, developed a sense
of commitment and confidence that Alliant
Energy would be a partner in developing a
strategy to prevent monitored concentrations
above the standard.
A Necessarily Holistic View
To demonstrate this partnership, Alliant Energy
commissioned a study by an independent
research group to analyze the impact
that an SO2
nonattainment designation in the
area might have on economic development.
Internally, Alliant Energy initiated activities
to analyze its potential impact on the
monitored SO2
values and what the company
might be able to do to mitigate its contribution.
While it was clear that operations at
PCGS could be affecting the data the monitor
was collecting, it was also apparent that
other SO2
■ Contractual agreements
■ Operational performance
■ Regulatory impacts
■ Shareholder considerations
Developing a balance in these matters required
a proactive approach to decision-making
while maintaining frequent, collaborative,
and transparent communications with stakeholder
groups internally and externally.
Alliant Energy has an unyielding responsibility
to provide safe, reliable, and
responsible energy to its customers. Any
decisions made to address the SO2
related to particulate matter and mercury collection
efficiencies of the plant's electrostatic
precipitators necessary to meet the recently
promulgated Utility Mercury and Air Toxics
Standards (MATS). Although the use of lower-sulfur
coal posed a few logistical issues to
overcome, it was determined that the use of
the fuel was feasible, and it was moved forward
fully in 2015.
Success
During 2015, the SO2
above the 1-hour SO2
monitor in Tait
Cummins Park did not register any hourly
SO2
concentrations that were found to be
standard (Figure 4).
The fourth-highest daily maximum 1-hour
reading for the year ended up being 49.7
ppb, a significant difference from the year
before.
As of the writing of this article in late
February, 2016 has continued that trend.
While it cannot be said that the fuel changes
are the sole reason that monitored SO2
conmatter
would
need to be in line with that obligation.
While other environmental regulations
may affect future investments in PCGS,
Alliant Energy analyzed the possibility of
moving forward using a lower-sulfur coal
than what the plant had been utilizing, coupled
with some natural gas blending that
could be accommodated under the plant's
current configuration, especially since other
changes were anticipated.
Alliant Energy conducted several air quality
modeling exercises to assess the impact
that reductions in PCGS stack emissions
might have on predicted concentrations of
SO2
, not only at the monitor, but also in the
area where models were predicting the highest
concentrations might occur. The modeling
methods and results were shared with the
LCPHD and the IDNR and were found to be
consistent with their methods.
Although only the predicted PCGS
emitting sources, including idling
mobile sources, likely had an influence.
In developing a strategy, Alliant Energy
determined that whatever steps it may decide
to take would have to be holistically evaluated.
There were several competing influences
that might affect operations at PCGS
as well as Alliant Energy's electric and steam
customers and the community. Those considerations
included:
■ Additional emerging air, water, and solid
waste environmental programs and forthcoming
EPA requirements
■ Fuel availability
April 2016 | POWER
emissions impacts were reviewed, the
models determined that reductions in stack
SO2
emission rates brought on by a fuel
change within the current abilities of the
plant could have a measurable effect on
SO2
concentrations in the area. But before
such a change could be implemented, Alliant
Energy needed to understand whether
using such fuel would have operational or
other impacts on the plant and its ability to
live up to its responsibilities.
The lower-sulfur coal was strategically introduced
to the fuel stream to analyze operational
effects and any impacts it might have
on combustion byproducts, especially as they
www.powermag.com
centrations have been considerably lower,
the fuel change likely had a contributing
effect. Time will tell whether future influences
such as other SO2
-emitting sources,
the weather, and other contributors may affect
the monitor's readings.
Although the monitor's data collection
won't provide LCPHD and the IDNR with
the ability to recommend an attainment designation,
the ambient air quality modeling
that was conducted to support this decisionmaking
will be a strong tool in making that
recommendation in the near future. In addition,
it now seems possible to avoid a nonattainment
designation for the region.
The primary lesson learned is that a proactive,
collaborative, and transparent approach
to problem solving-coupled with a willingness
to communicate with stakeholders-
goes a tremendously long way.
Alliant Energy appreciates the willingness
of its stakeholders-especially those
officials in Linn County, Iowa, in this
instance-to engage in productive discussions,
develop well-thought-out messages,
and assess the many options that may be in
the best interest of those affected. By developing
a clear understanding of the impacts
and possibilities, an ability to develop smart
and flexible solutions was created, with
time to adapt before an undesirable result
was upon us. Without this communication,
competing objectives might have been developed
that could have had a detrimental
effect on the common goal. ■
-Jeffrey Hanson, PE (jeffreyhanson
@alliantenergy.com) is senior manager-environmental
and decommissioning services
for Alliant Energy. This case study was also
shared at the 2016 EUEC conference.
69
SO2 (ppb)
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POWER April 2016

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