Case Studies

Region: PJM (ComEd Zone)
Project Type: Utility-Scale Wind Generation
Capacity: ~100 MW Class
Issue Type: System Stability / Short Circuit Ratio (SCR) Constraint
Savings: ~$160M (≈90% reduction in network upgrade cost)

The Challenge

A utility-scale wind project sought to interconnect into a constrained 138 kV network with significant existing generation concentration and limited outlet capacity. Interconnection studies identified:

Very low Short Circuit Ratio (SCR ≈ 1.7) at a critical 138 kV substation

A weak system condition vulnerable to stability issues under N-1 contingencies

High sensitivity to a single 138 kV line outage

Total generation in the area approaching ~670 MW across only two grid outlets

Under traditional planning assumptions, the project triggered a major transmission expansion.

Traditional Utility Mitigation Outcome

The initial mitigation approach required:

Construction of a new 138 kV transmission line from a neighboring substation

Capital cost of approximately $180 million

Long permitting, siting, and construction timelines. High schedule and execution risk relative to project size. This solution rendered the project economically marginal to non-viable.

EDGE-Style Alternative Approach (GET-Enabled)

Instead of accepting the default transmission build, the interconnection strategy focused on: Root-cause analysis of the constraint (SCR-driven stability, not thermal overload)

Identifying whether the system weakness could be addressed locally and dynamically

Evaluating grid-enhancing technology (GET) solutions that could modify line impedance and power flow during contingency conditions.  A GET-based mitigation strategy was proposed and validated through stability analysis, demonstrating that: The N-1 stability issue could be resolved without adding a new transmission line. System strength could be improved by reducing effective impedance on the critical path. Reliability criteria could be met without increasing transfer limits beyond safe bounds

Outcome

Network upgrade cost reduced from ~$180M to ~$20M

~$160M in avoided transmission capital

Order-of-magnitude improvement in project economics. Significantly reduced schedule, permitting, and execution risk. A viable interconnection pathway aligned with utility reliability requirements

Region: PJM
Project Type: Utility-Scale Renewable Portfolio (Solar + Storage) Scope: 20+ Active Queue Projects
Total Network Upgrade Exposure: ~$3.8B
Primary Risk Driver: System Reliability Upgrades
Client Type: Infrastructure Investor / Platform Developer

An infrastructure investor evaluating a large PJM development portfolio faced material uncertainty around interconnection cost exposure.

While individual projects appeared attractive on a standalone basis, the portfolio as a whole carried:

• Approximately $3.8B in total network upgrade exposure
• Over 80% of costs driven by system reliability upgrades, not POI facilities
• Cost drivers that were often:
  • Identified late in the process
  • Non-linear in magnitude
  • Binary in outcome (projects either proceed or fail)

Traditional diligence approaches treated these upgrades as fixed outcomes, offering little insight into which risks were structural versus potentially mitigable.

EDGE conducted a scoped, fixed-fee portfolio interconnection risk assessment focused on PJM TC2 projects.

Rather than redesigning projects, the analysis was structured to inform capital allocation decisions, with emphasis on:

• Differentiating system reliability upgrades vs. physical interconnection facilities
• Identifying where upgrade exposure was driven by:
  • Steady-state thermal constraints
  • Voltage limitations
  • Stability or short-circuit conditions
• Flagging projects where:
  • Costs were likely binary & gating
  • Traditional siting screens overstated downside
  • Early technical optionality existed through sequencing, configuration, or GET-aligned strategies

The output was IC-ready and designed to support investor-level decision-making—not engineering rework.

The portfolio review revealed that:

• A relatively small subset of projects accounted for a disproportionate share of total upgrade exposure
• Many high-cost projects were driven by system reliability constraints, not absolute transmission scarcity
• Several projects previously viewed as “non-viable” warranted re-examination under an interconnection-first lens
• Even modest optionality at the project level had outsized implications at the portfolio level

• Improved clarity around true downside risk vs. perceived risk
• Ability to prioritize capital deployment toward projects with higher probability of success
• Identification of projects where early mitigation strategy could materially change outcomes
• Avoided treating all upgrade exposure as fixed or inevitable

While no single project redesign was performed, the analysis materially improved investment confidence and portfolio strategy.

This case illustrates a second core EDGE principle:

Interconnection risk is increasingly a portfolio-level investment issue, not a late-stage engineering problem.

In congested regions like PJM, understanding which costs are binary, which are structural, and which may be mitigablecan materially influence valuation, sequencing, and go/no-go decisions.

• System reliability upgrades now dominate interconnection cost exposure in PJM
• Many outcomes are binary and identified too late to influence strategy
• Portfolio-level screening can surface asymmetric risk and opportunity
• Early clarity enables better capital discipline and faster decisions