Nicor Gas Commercial Rates & Procurement Guide for Illinois Businesses

Nicor Gas remains your utility regardless of supply choice. Delivery charges fund distribution mains, metering, safety programs, and ICC-approved returns. Supply charges reflect the commodity and balancing costs from your chosen retail supplier—or Nicor's default gas purchase if you do not shop. Commercial bills typically show therms consumed, delivery rate per therm, supply rate per therm, customer charge, and taxes.

Delivery Components Explained

Delivery includes fixed monthly customer charges and volumetric rates that may tier by annual usage. Large commercial and industrial users may sit on different rate schedules than small general service accounts. Demand-related gas charges are less common than electric demand but interruptible service options exist for certain load profiles. Review your rate classification annually—usage growth can bump you into a different schedule.

Default Supply vs Retail Choice

If you never procured supply, you pay Nicor's default purchase gas adjustment (PGA) or equivalent mechanism—often acceptable short term but rarely optimal for multi-year budgeting. Switching requires a Letter of Authorization and 1–2 billing cycles; timing matters before winter. See Nicor Gas tariff sheets and ICC filings for current delivery rates.

• Separate delivery from supply when benchmarking $/therm year over year.
• Compare supplier quotes on identical swing and basis assumptions.
• Verify tax exemption certificates are on file for qualifying nonprofits.
• Check meter read type—estimated reads distort true-up reconciliation.

Nicor's service territory spans suburban corridors from Rockford south through Aurora, Naperville, and parts of the Fox Valley—manufacturing and logistics nodes with significant process gas loads beyond space heating. Process loads often have less weather correlation, improving supplier forecasting and potentially unlocking tighter fixed pricing than pure office portfolios.

Illinois commercial gas choice enrollment requires matching account numbers and service addresses exactly; typos delay switch windows past intended winter start. Maintain a master spreadsheet of meter numbers, contract expiration, swing tolerance, and primary contact—multi-site operators lose leverage when RFPs omit smaller meters suppliers deem nuisance accounts.

Reading the Nicor Bill Line by Line

Nicor commercial invoices group delivery charges under headings referencing ICC-approved tariffs—GT-1, GT-2, and large volume schedules each carry different customer and volumetric components. Match your account classification letter to the tariff PDF on Nicor's site monthly; misclassification persists until you file a formal rate schedule change request with supporting therms history.

Balancing charges on default supply reflect Nicor's cost to procure gas for default customers—shopping supply moves balancing to your retail supplier's contract definition. Compare 'total therms' to 'billed therms' after weather normalization clauses in some contract types.

Seasonal businesses—parks, seasonal manufacturers, event venues—should normalize therms to operating days before RFP. Suppliers applying annual swing to seasonal profiles trigger penalties; propose monthly band contracts where available.

Multi-Site Nicor Portfolios

Franchise and retail operators with ten or more Nicor meters should aggregate volume in RFPs while preserving location-specific swing bands. National suppliers entering Illinois markets may offer attractive initial quotes but lack historical basis performance data during Midwest cold events—request Illinois reference customers before award.

Property managers reconciling CAM should disclose whether gas is grossed up for occupancy variance or billed on actual therms per tenant. Gross-up errors systematically overcharge retail tenants during low-occupancy periods following lease expirations.

Warehouse operators heating dock doors with gas infrared should separate dock therms from space heat in RFP volume bands—suppliers pricing blended profiles misestimate swing when shipping seasonality shifts.

Nicor commercial accounts in Kane and DuPage counties often share campuses with ComEd electric service—review gas swing when electric cogeneration or heat pumps shift thermal load between fuels.

Fixed-price gas contracts lock $/therm for the contract term on a defined volume, transferring price risk to the supplier. Index pricing follows NYMEX plus basis and supplier adder, exposing you to daily or monthly market moves. Hybrid strategies block-fix a winter strip and float shoulder months—common among experienced Illinois buyers.

When Fixed Pricing Wins

Choose fixed when your budget requires certainty, your volume is stable, and forward curves sit below historical averages. Manufacturing plants with tight COGS targets, hospitals, and schools often prefer 12–24 month fixed strips through winter. Lock before storage withdrawal season accelerates if analysts project cold El Niño or polar vortex risk.

When Index Pricing Wins

Index works when you can tolerate month-to-month variance, have swing flexibility to curtail non-essential gas use during spikes, and forward curves are elevated—betting on mild weather or storage surplus. Warehouses with air-curtain losses should fix after sealing upgrades, not before.

Use a transparent broker to compare supplier margin, basis definitions, and rollover clauses. Illinois licensed gas suppliers must disclose fees; still read pass-through language for pipeline surcharges and regulatory changes per ICC natural gas rules.

Collar structures cap index upside while preserving some downside participation—useful when NYMEX is elevated but analysts forecast mean reversion. Collars carry premium costs embedded in supplier margin; compare collar all-in to plain fixed over identical volumes using Monte Carlo weather scenarios if your team supports it, or simpler high/low forward strip analysis if not.

Interruptible gas tariffs exist for qualifying Nicor accounts willing to curtail during system emergencies—rare for most C&I but relevant to large thermal loads. Confirm whether interruptible discounts apply to delivery, supply, or both before relying on savings in budgets.

Layered procurement fixes 50% of forecast winter therms in September, 25% in October, and floats 25% on index—averaging entry points without single-date timing risk. Document tranche decisions in procurement memos for audit trails required by some manufacturing ISO certifications.

Creditworthiness affects supplier deposit requirements—nonprofit and startup commercial accounts may face letters of credit demands that alter effective pricing. Disclose financial covenants early in RFP to avoid re-trades after award.

Financial hedging with NYMEX futures differs from retail supply contracts—treasury teams occasionally duplicate hedge layers when gas suppliers already embed futures in fixed quotes. Align treasury and procurement calendars to avoid paying twice for the same winter strip protection.

Food processors along I-88 corridors should align gas RFP volume with production expansion timelines—suppliers price growth assumptions into multi-year fixed strips and penalize shortfalls at true-up.

Northern Illinois gas demand peaks December through February when heating degree days accumulate. Procurement calendars should target April–June and September–October windows for winter strips—liquidity is higher and weather uncertainty partially priced. Waiting until November forces acceptance of winter premiums embedded in forwards.

NYMEX vs Local Basis

Henry Hub futures on NYMEX are the benchmark, but Nicor balancing reflects local pipeline constraints and storage levels. Basis blowouts during Polar Vortex events added $1–$3/MMBtu equivalents in historical events. Contracts should define basis clearly and cap pass-through pipeline surcharges where possible.

1. 1Review EIA storage reports weekly starting September.
2. 2Request supplier forward curves with Chicago/Northern Illinois basis assumptions.
3. 3Layer 25–50% winter volume early; add tranches on dips.
4. 4Align gas hedge calendar with electric capacity procurement if co-gen.

Businesses with food processing loads should coordinate gas procurement with production schedules—unexpected downtime still triggers minimum bill volumes on some contracts.

Pipeline maintenance windows in October can widen basis even when NYMEX appears calm—suppliers may pass through incremental transportation surcharges defined in contract fine print. Request historical pass-through examples from three winters before accepting index products from new suppliers entering Illinois after national mergers.

Coordinate storage hedge awareness: when Midwest storage five-year averages fall below norms by September, winter fixed premiums historically firm. EIA weekly storage reports publish Thursdays—procurement committees should review through October before primary lock decisions.

Industrial users with cogeneration should verify gas contract swing aligns with electric export hours—misaligned hedges leave thermal load exposed when turbines ramp down during ComEd peak events. Integrated advisors model both commodities from one interval dataset.

Prepare for polar vortex scenarios even in climate variability discussions—January 2019 and similar events remain reference cases for Illinois basis stress testing in supplier negotiations.

Hedge timing meetings should include operations leadership who know shutdown schedules—maintenance outages reduce gas pull and affect swing calculations during contract true-up.

Industrial cogeneration users selling power back to grid under PURPA or similar arrangements should model gas procurement against electric output schedules—misaligned gas swing causes imbalance penalties that exceed commodity savings from index pricing.

• Review NYMEX strip monthly August through October.
• Compare at least three supplier basis quotes.
• Document hedge decisions in board or owner minutes.
• Reconcile contract therms to AMR meter reads quarterly.

Request supplier performance bonds on large winter strips when counterparty credit is unclear—Illinois commercial gas market consolidations continue shifting retail supplier ownership.

A structured bill audit 6–9 months before contract expiration surfaces errors and informs RFP volume assumptions. Many Illinois businesses discover wrong rate classes, missing tax exemptions, or supply swing penalties only after multi-year drift.

Audit Checklist

• Reconcile therms to production or HDD models—flag >15% unexplained variance.
• Confirm delivery rate schedule matches ICC tariff for your SIC/NAICS class.
• Match supply contract price to billed supply rate each month including true-ups.
• Review balancing charges vs contract swing tolerance (often 10–20%).
• Check duplicate GSA accounts after mergers or meter changes.

Upload bills to our bill analyzer to visualize supply vs delivery trends. Pair results with load factor tools if the same site has significant electric load. Document findings before engaging suppliers—accurate volume bands improve quote competitiveness.

Nicor billing disputes route through utility customer service first, then ICC consumer division if unresolved. Document every variance with therms, temperature normalization, and contract swing calculations in writing—verbal promises from supplier sales reps rarely bind billing departments.

After audit correction, re-bid supply with normalized volumes—suppliers who priced high swing tolerance on inflated baselines will drop quotes materially when presented accurate data. Treat audit findings as RFP input, not just error correction.

True-up invoices arriving six months post-contract often surprise accounts that changed production volumes—build swing tolerance at 115–125% of normalized therms if production variability is structural, not temporary.

Maintain scanned PDF archives of every Nicor bill for seven years—ICC complaint processes and supplier disputes require original line-item detail often unavailable from utility portals after 24 months.

Supplier bankruptcy risk is lower for gas than electric retail but not zero—include successor assignment and supplier of last resort language mirroring lessons from Illinois electric supplier market exits in prior years.

After audit, update energy budget forecasts for next fiscal year with corrected $/therm assumptions—finance teams often carry outdated gas costs forward after procurement saves money.

AMR meter deployment across Nicor territory improves daily therm visibility—use granular reads to catch leaks and equipment faults before they distort supplier true-ups.