POWER August 2021 - 27

TRANSMISSION & DISTRIBUTION
rience, there are obviously other challenges
involved when routing cables at
sea. Treseder explained that the regulatory
hurdles are the same for AC or DC
lines, so while the decision on which
technology to use hinges on a variety
of factors, the distance from shore is a
primary consideration.
" Our Beacon Wind project, which is
2. The SOO Green high-voltage direct-current (HVDC) Link will connect a MISO terminal at the
Killdeer Substation, southwest of Mason City, Iowa, with a PJM terminal at the Plano Substation,
in Yorkville, Illinois. The link will have a capacity of about 2 GW. Courtesy: Direct Connect
Development Company
underground primarily along existing
railroad rights-of-way to make the connection.
Minneapolis, Minnesota-based
Direct Connect Development Company
is heading the project.
During the ARPA-E session, Trey
Ward, CEO of Direct Connect, provided
specifics about the project. " [SOO
Green] is the first transmission project
in the U.S., that's going to be co-located
underground along railroads and highways
for its entire 350-mile route. So,
we don't need eminent domain to secure
right-of-way for our transmission
line, " he explained.
" It's just two slender cables that are
buried in railroad right-of-way, and each
cable is no bigger around than a wine
bottle. So, it's really out of sight and out
of mind. And what this does is it avoids
landowner opposition, and it expedites
the permitting because there's no avian
or viewshed impacts. So, what that
means is we can go fast. Co-location in
transportation corridors provide us the
advantage of speed in development,
and speed is key, because as we know,
everything in the climate and energy
world is changing quickly. The weather's
changing, the technology's changing,
and our grid's changing, " Ward said.
" SOO Green will also provide a lifeline
between two of the largest power
markets in the U.S.-the Midwestern
and East Coast power grids. That'll
help both of those grids avoid Texassized
blackouts, " said Ward. " And that's
in addition to delivering over 2 GW of
Midwestern wind to Eastern markets, "
he added.
" The modern HVDC technology that
we'll be using also makes our grid climate
resilient. Besides being underground
and enabling reserve sharing
between those markets, it also provides
August 2021 | POWER
a lot of ancillary services that bring stability
to the AC [alternating current] grid
and helps to keep the lights on in a highrenewable
scenario, " said Ward. " When
it goes into service, SOO Green will be
the most dynamic resource on the entire
North American grid, and the largest
of its kind in the world. "
Yet, as significant as the SOO Green
project could be for the MISO and PJM
markets, the impact pales in comparison
to the potential effect it could have
on the larger U.S. power grid. Ward believes
SOO Green will provide the model
for a climate-resilient clean-energy
grid. " We believe we've built a better
mousetrap with SOO Green, " he said.
" This is the way transmission should
be built in the U.S.-in an environmentally
responsible manner that respects
landowner rights-and we can replicate
it across the country to put union labor
to work building the grid of the future. "
Transmission Systems Key to
Offshore Wind Expansion
Elisabeth Treseder, New England market
lead with Equinor, an international energy
company headquartered in Norway that
develops oil, gas, wind, and solar energy
projects around the world, was another
panelist for the session. She said HVDC
systems can provide several benefits for
offshore wind projects. " As we move
projects further from shore for various
reasons, including the water depths and
visibility issues or environmental issues,
we have to increasingly come up with
transmission solutions that are going to
be efficient, and HVDC in that scenario
presents a very attractive option for offshore
wind, " Treseder said.
Although offshore wind projects
don't face the same right-of-way issues
that on-land transmission projects expewww.powermag.com
off
the coast of New England, is delivering
power into New York City, and we
have a 170-nautical-mile cable route buried,
and so, a cable corridor of that length
requires the use of HVDC, " Treseder
said. She referenced Ward's likening of
an HVDC cable's diameter to the size
of a wine bottle, and said the " relatively
small, single-cable bundle to bring, in our
case, over 1,200 MW of power to a load
center " is a big benefit.
" That's really significant efficiency,
because we can reduce the amount of
offshore installation required and the
number of cables to bring that significant
amount of power [to shore], " said Treseder.
" So again, in terms of hurdles, we've
actually found that HVDC reduces them
rather than creates new ones. "
Ward agreed that HVDC systems are
a great option for long-distance transmission.
" With its low line losses over long
distances, it's uniquely suited, I believe,
to integrating remote renewables to load
centers. And again, it provides that lifeline
to neighboring markets in a climatechanging
world because they can share
the reserves, " he said.
A Win-Win Scenario
The beauty of HVDC transmission interconnections
is that they aren't just oneway
solutions. Power can be wheeled
in either direction based on the need.
Therefore, the system can help decarbonize
the grid at both ends of the line
given the geographic and generation diversity
that exists between them.
Using SOO Green as his " real-world "
example, Ward explained: " SOO Green
from Iowa to Illinois, we're enabling lowcost
Midwestern wind to reach Eastern
markets. But as Illinois builds out its solar
footprint, the flows on our line will
reverse when the wind dies down in
Iowa and the sun is shining in Illinois.
And so, that will reduce the need to turn
on the baseload fossil fuel generators in
Iowa, even when the wind's not blowing,
which further decarbonizes Iowa as
well. So, it's really a case of neighbors
helping neighbors. " ■
-Aaron Larson is POWER's
executive editor.
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POWER August 2021

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