High Level
A peer reviewed study from Northwestern University in Nature
Communications concludes that transmission congestion prevents clean generation
from reaching EV chargers at scale, erasing a large share of the transportation
emissions reductions that electrification should deliver. The authors find that
modest, targeted increases in transmission capacity can recover most of the
lost benefits and prioritize interregional links and known bottlenecks as high‑value
upgrades.
Full View
Study finds grid congestion erases EV emissions gains;
3%–13% capacity increase restores benefits
• What happened: On Aug. 6, 2025, Northwestern University researchers
published modeling showing that, under current grid constraints, about one
third of potential EV‑related emissions reductions are lost because clean power
cannot reach high‑demand charging locations. In their nationwide scenarios,
eliminating congestion required as little as a 3.4% transmission capacity
increase with today’s generation mix and about 13.4% when renewable capacity
equals nonrenewable capacity.
• Who did it: Chao Duan and Adilson E. Motter, Northwestern University;
published in Nature Communications.
• Why they did it: To quantify how delivery constraints, not just the
generation mix or smart charging, limit EV emissions reductions and to identify
least‑cost, targeted upgrade ranges to relieve congestion.
• Stakeholder views: Adilson Motter, Professor of Physics, Northwestern
University: “Even if the U.S. fully adopts EVs and generates enough renewable
electricity to charge them, it still won’t be enough… The power lines are
congested, and that leads to congestion‑induced CO₂ emissions.”
• What happens next: The authors recommend targeted reinforcements and
stronger interregional ties across the Eastern, Western, and Texas
interconnections. Planners can use the 3% to 13% benchmark as a policy‑ready
range for congestion relief aligned with EV corridor deployment and renewable
buildout.
Northwestern Now, “Clean energy is here. Getting it to EVs
isn’t,” Aug. 6, 2025
Nature
Communications, “Grid congestion stymies climate benefit from U.S. vehicle
electrification,” Aug. 6, 2025
Innovation News Network, “US transmission grid upgrades crucial
to realising EV transition, says Northwestern University,” Aug. 7, 2025
What’s the So What?
To grid people, this is a quantitative “well, duh.” Still,
it matters. A peer reviewed model that shows congestion wipes out a big share
of EV emissions gains turns a lived industry truth into evidence a legislature
or court can understand. It reframes the cost debate: single‑digit to low‑teens
percent capacity additions in the right places buy back emissions reductions
that charging optimization alone cannot deliver.
This is also affirmation that advocates are on the correct
side of the fight. When “fiscally responsible” legislators argue that new lines
are a blank check, this study supplies a narrower ask and a measurable payoff.
It makes the case for targeted reinforcements and a handful of interregional
ties that convert stranded clean megawatt‑hours into cleaner miles driven, with
an analytic basis rather than a slogan.
For developers, utilities, and states, the operational
takeaway is to pair highway‑corridor charging plans with congestion relief, not
treat them as separate programs. For federal and regional planners, the signal
is to prioritize incremental capacity additions on existing corridors and
specific interregional upgrades where they unlock the most emissions benefit.
None of this requires a moonshot. It requires using the grid we have as the
backbone for the grid we need.
Bibliography
Northwestern Now. “Clean energy is here. Getting it to EVs
isn’t.” Aug. 6, 2025.
Nature
Communications. “Grid congestion stymies climate benefit from U.S. vehicle
electrification.” Aug. 6, 2025.
Innovation News Network. “US transmission grid upgrades crucial
to realising EV transition, says Northwestern University.” Aug. 7, 2025.