POWER February 2021 - 20

CONNECTED PLANT
How NRG Energy Uses IIoT
Technology to Optimize Asset
Performance and Predict Failures
Industrial Internet of Things (IIoT) technology is changing how power plants
operate. One generating station incorporated new wireless vibration sensors with
data from its existing historian system to better identify and understand problems
on a real-time basis.
Calvin Arnold, Mitch Levings, and
Juli Iacuaniello
N
RG Energy is a leading power generator
and retailer with 35 generating
facilities producing 23 GW
of power to help meet the needs of more
than 3.7 million residential, small business,
and commercial and industrial customers
served through a diverse portfolio
of retail brands. NRG has committed
to cutting its carbon emissions in half by
2030, even as the company expects to
continue growing.
NRG recognizes the role technology will
play in this transformation and how Industrial
Internet of Things (IIoT) devices can
help improve efficiency, and optimize how
power is produced and consumed. In a
blog post on the company's website, NRG
shared its vision of what IIoT connectivity
can provide, which is, " a real-time view of
energy as it is generated and consumed,
not just at a corporate level but at a utility
and soon, perhaps, a grid level. "
Several of NRG's generating plants are
in Texas, which operates a competitive
energy market through the Electric Reliability
Council of Texas (ERCOT). ERCOT
is the independent system operator (ISO)
that controls about 90% of the electricity
distribution in Texas. Unlike other ISO
markets, which use longer-term forecasting,
the prices in the ERCOT market are
determined daily through an exchange,
based on available capacity and demand.
The 3.7-GW W.A. Parish generating
station, located about 25 miles southwest
of Houston, is the largest power
plant in the NRG fleet. These days, it
needs to be available to respond to everchanging
load demand, because generating
units designed to run at a steady
baseload are now operating at variable
loads, with some units even being
stopped and restarted daily to meet demand
at certain times of the year. Such
20
flexible operation places new stresses
on the equipment and makes failure detection
more challenging. At W.A. Parish,
IIoT sensors have been combined
with process data to improve availability
and reliability.
Continuous Improvement of the
Asset Reliability Program
Equipment reliability at NRG means the
difference between meeting its power
generation commitment or purchasing
from competitors on the open market.
NRG has an existing well-developed
predictive maintenance (PdM) program,
which includes infrared thermography,
oil analysis, and vibration analysis, but
the company sought to supplement its
monthly walkaround data collection with
more frequent readings under differing
load conditions.
To better assess equipment condition,
additional data collection was required,
so the NRG team decided to add continuous
wireless asset monitoring that
would provide more frequent data and
allow earlier detection of developing failures.
Going wireless was desirable because
wiring the sensors into the plant's
distributed control system (DCS) would
have made the program cost prohibitive.
The PdM team also recognized the
benefit of combining asset condition data
with historical process data from its OSIsoft
PI System. The combination of the
two systems was useful to both the PdM
team and process engineering. The PdM
team wanted to use process data to have
a more comprehensive ability to detect
failures. The process engineering team
wanted to use the data to improve plant
performance by understanding the impact
of process variability on asset condition.
With their mutual interests in mind,
the two groups decided to form a multidisciplinary
team to define the requirewww.powermag.com
1.
This example shows data within the
OSIsoft PI System that includes the combination
of vibration and process data on a single
screen. Courtesy: NRG Energy
ments and establish goals for the usage
of continuous asset condition data. The
requirements that they defined were:
■ Cost effectiveness-wired systems
were cost-prohibitive.
■ Integrate with the PI System.
■ Easy to deploy.
■ Easy to use.
After considering various wireless systems,
NRG selected Petasense's vibration
motes and Asset Reliability & Optimization
(ARO) system to monitor 13 critical
pumps and motors, including steam- and
motor-driven
boiler
feed pumps and
condensate pumps, and a startup boiler
feed pump that runs only during startup
and shutdown. Continuous monitoring
of these pumps provided consistency in
the vibration readings, as several of the
pumps operate at variable speeds and
loads. The periodic nature of walkaround
systems makes it difficult to take readings
under consistent operating conditions.
By including process data such as flow,
speed, and load from PI in the analysis,
the PdM team is able to more accurately
determine an underlying failure.
The vibration motes collect vibration
and temperature eight times per day,
which is sent to Petasense's cloud-based
software to provide on-demand alerts to
the PdM team of developing problems.
This allows for improved efficiency, as
POWER | February 2021
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POWER February 2021

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