Nicor Gas Troy Grove

At a Glance
• System Configuration: 2 × C600S Stand Alone Capstone Microturbines with a fully redundant controller
• Annual Generation: >5,000 MWh/year of reliable, continuous on-site electricity
• Financial & Operational Impact: ~$100,000 / year in direct fuel cost savings, plus an estimated $0.02 / kWh reduction in ongoing maintenance expenses
• Critical Infrastructure Anchor: Commissioned in 2023; powers the largest of Nicor Gas's eight underground aquifer storage fields, holding 50 billion cubic feet (Bcf) of natural gas capacity


The Challenge
Nicor Gas (a division of Southern Company) supplies natural gas to over 2.2 million residential, commercial, and industrial customers across 650 Illinois communities. The utility's flagship Troy Grove storage facility in LaSalle County holds roughly 50 Bcf of natural gas—one-third of Nicor Gas's total 150 Bcf underground storage capacity. During polar vortexes and arctic blasts, natural gas drawn from storage accounts for approximately 50% of all energy distributed across the state.
Powering the high-demand gas compression and storage operations at this remote, off-grid site previously relied on aging, high-maintenance reciprocating engines. These older engines required continuous on-site operators, intensive monthly maintenance, frequent oil and filter changes, and regular site downtime that threatened the reliability of seasonal gas delivery.


The Solution
Nicor Gas partnered with Veristar to replace the legacy engines with a 1.2 MW off-grid, microturbine-based generation system featuring two Capstone C600S microturbines managed by a fully redundant controller.
• Autonomous Off-Grid Reliability: Delivers continuous, highly stable 24/7/365 electricity to drive critical gas storage and compression infrastructure without requiring connection to the electrical grid.
• Low-Maintenance Air-Bearing Architecture: Utilizes oil-free, air-bearing technology that eliminates fluid changes, spark plug replacements, and heavy mechanical wear, drastically cutting site maintenance requirements.
• Operator-Free Remote Monitoring: Operates continuously without requiring dedicated full-time on-site personnel, managed seamlessly through Vergent's advanced MTIM control system.
• Cold-Weather Operational Resilience: Ensures uninterrupted winter operation during extreme sub-zero weather events when gas withdrawal demand reaches its annual peak.


The Results
• Annual Fuel Savings: Optimizes single-fuel combustion efficiency, yielding $100,000 in annual fuel savings compared to legacy reciprocating engines.
• $0.02 / kWh Operational Cost Reduction: Cuts ongoing maintenance and overhaul expenses by two cents per kilowatt-hour, maximizing long-term equipment ROI.
• Zero Unplanned Down Time: Eliminates frequent monthly engine maintenance outages, safeguarding the continuous flow of heating gas during critical freeze events.
• Secures State-Wide Energy Reliability: Delivers reliable power to support the gas reserves that heat northern Illinois homes and businesses through severe winter weather.