Advisory Overview and Strategic Implications
Executive Context
This review is being provided by Halo Advisory Group for its energy practice clients to support informed decision-making amid a rapidly changing reliability and policy landscape in Illinois.
Illinois is entering a decisive period for electric reliability. Rapid load growth, accelerated generation retirements, interconnection bottlenecks, and ambitious clean energy mandates are converging to create measurable resource adequacy risk through the next decade. The 2025 Illinois Resource Adequacy Study provides the most comprehensive, probabilistic assessment to date of whether Illinois can reliably meet peak demand under evolving market, policy, and infrastructure conditions.
For executives, regulators, utilities, large energy users, and investors, the study shifts the conversation from theoretical risk to actionable system constraints and investment priorities. Halo Advisory Group’s energy practice leverages these findings to help clients anticipate reliability exposure, align growth and sustainability strategies, and identify practical mitigation and investment pathways in an increasingly capacity-constrained market.
What the Study Assessed
The Resource Adequacy Study evaluates Illinois’ ability to maintain reliability across PJM and MISO footprints using industry-standard probabilistic modeling, including Loss of Load Expectation and Effective Load Carrying Capability methodologies. It integrates:
Load forecasts incorporating electrification, data centers, and large-load growth
Scheduled and policy-driven generation retirements
Renewable deployment trajectories under CEJA and FEJA
Interconnection queue realities in PJM and MISO
Transmission constraints and firm import limitations
Capacity market accreditation reforms are underway at both RTOs
This framework moves beyond reserve margin accounting to test real-world reliability under stress conditions.
Key Findings That Matter to Decision-Makers
1. Resource adequacy risk is structural, not cyclical
Illinois faces growing reliability exposure driven by the pace mismatch between load growth and dependable capacity additions. Delays in interconnection and transmission upgrades materially increase risk in near- and mid-term planning horizons.
2. Interconnection queues are now a primary bottleneck
Both PJM and MISO reforms improve long-term outcomes, but study backlogs, uncertainty in cost allocation, and readiness requirements constrain near-term capacity. Queue position does not equal deliverability.
3. Dispatchable and flexible resources remain critical
Even under aggressive renewable buildout scenarios, the system depends on firm, flexible capacity, including nuclear retention, storage with duration, demand response, and fast-ramping thermal resources to maintain reliability during extreme events.
4. Transmission is the hidden constraint
Transmission availability and upgrade timing increasingly dictate where and when the new generation can actually contribute to reliability. Resource adequacy is now inseparable from transmission planning.
5. Affordability and reliability are converging risks
Capacity scarcity, high auction clearing prices, and emergency procurement mechanisms directly translate into customer cost exposure. Reliability shortfalls are no longer abstract engineering concerns; they are balance-sheet issues for large employers and utilities.
Strategic Implications by Stakeholder
State Policymakers and Regulators
Resource adequacy must be treated as a continuous planning function, not a one-time study.
Alignment is needed between CEJA goals, interconnection realities, and reliability safeguards.
Mitigation planning should prioritize near-term deliverability over aspirational capacity.
Utilities and Load Serving Entities
Capacity procurement strategies must account for queue risk and accreditation uncertainty.
Transmission coordination and non-wires alternatives deserve elevated focus.
Demand-side flexibility is now a reliability asset, not just a cost-management tool.
Large Energy Users and Data Center Operators
Load growth assumptions are under scrutiny and may face curtailment risk
Proactive engagement in capacity, demand response, and on-site generation strategies is becoming essential
Reliability exposure increasingly affects site selection and expansion decisions
Investors and Developers
Value is shifting toward projects that clear interconnection, site control, and transmission hurdles quickly.
Storage, hybrid resources, and fast-track reliability additions carry a premium opportunity.
Illinois remains attractive, but execution risk has increased materially.
How Advisory Support Creates Value
An effective response to the Resource Adequacy Study requires an integrated strategy across policy, markets, infrastructure, and capital. Advisory support should focus on:
Translating study findings into board-ready risk and investment frameworks
Stress-testing load, capacity, and transmission assumptions for specific portfolios
Identifying near-term reliability solutions that are financeable and approvable
Aligning corporate growth, sustainability, and reliability objectives
Engaging constructively with regulators and RTO processes using data-driven positions
Bottom Line
The Illinois Resource Adequacy Study makes one reality clear: reliability is now the binding constraint on energy transition and economic growth. The winners will be those who move early to align capital, infrastructure, and policy with the physical realities of the grid.
This is no longer a question of whether action is needed, but who acts first and how strategically.
About Halo Advisory Group – Energy Practice
Halo Advisory Group advises companies, investors, and public-sector stakeholders operating at the intersection of energy, infrastructure, and policy. Our energy practice supports clients navigating resource adequacy, grid reliability, energy transition strategy, and large-load growth in increasingly constrained power markets.
We work with utilities, independent power producers, large energy users, data center developers, private equity sponsors, and policymakers to translate complex regulatory and market dynamics into clear strategic and investment decisions. Our approach integrates market analysis, policy insight, infrastructure realities, and capital strategy to help clients manage risk, protect reliability, and unlock value in evolving energy systems.