POWER July 2020 - 6

SPEAKING OF POWER
Minutes Matter in the
Energy Imbalance Market
Aaron Larson
n energy imbalance market (EIM)
is a voluntary market that provides
a sub-hourly economic dispatch of
participating resources for balancing supply
and demand every five minutes. One
such market is the Western EIM, which
the California Independent System Operator
(CAISO) began operating on Nov.
1, 2014. CAISO claims the Western EIM
enhances grid reliability and improves
the integration of renewable energy,
which leads to " a cleaner, greener grid. "
The Western EIM has grown from
meager beginnings-initially optimizing
only the CAISO and PacifiCorp balancing
authority areas-to a footprint that now
includes parts of eight states and a portion
of British Columbia, Canada. It has 11
active participants, with Salt River Project
and Seattle City Light entering the fold
this year, and 10 more participants are
slated to join by the end of 2022.
By all accounts, the market has been
a huge success. From its launch through
April 2020, CAISO reports the Western
EIM has generated $919.69 million in
gross benefits for its participants. However,
participating in the market keeps
power companies on their toes. The subhourly
five-minute increment dispatch
market means generating units need to
hit their output targets consistently. If
they don't, the company must pay.
A
Therefore, deviations were only being
identified by the power traders or the balancing
authority. They would in turn notify
the generating units that dispatch instructions
weren't being followed consistently,
which was a problem. Furthermore, APS
wasn't able to identify or correlate trends
to different modes of operation, because
it didn't have the necessary data available
to accomplish that task.
" From a marketing standpoint, our
drive is to have the unit work within the
parameters that we provide to the energy
imbalance market and to our balancing
area, and anytime the unit can't
achieve the targeted dispatch, then
something out there is sub-optimal, "
said Tim Rusert, director of Fuel Procurement
and Resource Operations Support
with APS. That can mean another unit is
forced to start unexpectedly, which is
costly and inefficient.
A Tool to Optimize Operation
That's where the unit monitoring tool
came in. KBC (a Yokogawa company)
was implementing OSIsoft's PI System
for APS, so it was natural for the companies
to work together on the tool.
" Our consultants are subject matter
Challenges Hitting Targets
Arizona Public Service (APS) began participating
in the Western EIM in October
2016. As a result, the company has benefited
to the tune of more than $150 million,
according to CAISO's records. But
until APS implemented a unit monitoring
tool, managing power generation wasn't
always easy.
" Prior to the unit monitoring tool,
compliance was managed off of our
automatic dispatch, or dispatch screen,
which basically consisted of a series of
tables and a single graph, " Andre Norwood,
senior engineer with APS, told
POWER. " The problem we had with
that was the operators found it a little bit
cumbersome and difficult to do. "
6
experts in implementing those types of
monitoring solutions for electric utilities, "
Marc Diamante, program manager with
KBC, said. " We bring practical experience
to the table. KBC's folks have worked
in plants and they've worn hard hats.
They've stood in the control room. So, we
were a very good fit based on the timing. "
" The unit monitoring actually started
off as a proof of concept, " Norwood said.
" What KBC brought to the table was its
experience in relational database, putting
that data in a nice visualization. And really,
what's important from a monitoring and diagnostics
standpoint, gleaning events from
that information and giving summaries. "
Diamante explained that after more
than three years of use, the tool is well
beyond the proof-of-concept stage. The
base product KBC built measures dispatch
compliance against unit operating
limits and performance. It also tracks
the operating modes utilized by the enwww.powermag.com
ergy
control center and operations. It
provides trending capabilities and allows
easier data visualization. Late last year,
enhancements were made that include
unit dispatch and startup metrics. KBC's
goal was to provide even more historical
and granular information for APS's team
to analyze so operators could further improve
unit performance.
Continuous Improvement
APS uses the unit monitoring tool on
a total of 40 coal, combined cycle, and
combustion turbine units. The tool is also
being considered as an option for solar
and wind projects. And more improvements
may be coming soon.
" It's a journey, " Diamante said. KBC is
collecting data to further support analytics
from a fleet performance perspective.
" We're integrating with tools like
Power BI [a Microsoft product], so we
get advanced analytic capabilities, accumulating
lots of historical data. There's
a pretty significant potential with a very
large amount of historical data to start
looking at leveraging machine learning
out into the future-take it to the next
level with even more advanced technologies
than what we have been using up to
this point, " he said.
Prior to joining the EIM, APS was simply
in a non-organized bilateral market,
which was based on hourly transactions.
Any differences could be made up for by
moving other units' generation around.
In the EIM, however, if the company
doesn't hit its five-minute target, APS is
faced with a financial impact.
" The ultimate benefit that we're
achieving with this tool is a much more
precise unit operation window of knowing
what our units can do and hitting the
numbers, " said Rusert. " If a market operator
asked for a unit to be at 250 MW,
and we hit the 250, that's a win. Otherwise,
if we're at 245 or close, we've got
to make that up with something else. "
" Minutes matter in the energy imbalance
market, " said Diamante, so having a
tool to keep units on target is a must. ■
-Aaron Larson is POWER's
executive editor.
POWER | July 2020
http://www.powermag.com
POWER July 2020

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