Chattanooga Gas Company Rate Selection Guide
Chattanooga Gas Company is a Southern Company Gas subsidiary distributing natural gas to roughly 39,316 customers in Hamilton and Bradley counties, Tennessee, regulated by the Tennessee Public Utility Commission. Its strongest C&I data channel is a comprehensive ANSI X12 EDI program (814 consumption history, 810 e-billing, 820 payments) with trading partner enrollment, while the My Account portal provides 13 months of billing and monthly usage history.
Market Overview
TPUC-regulated gas distribution utility owned by Southern Company Gas. Pricing and rate plans for business customers are published on the company's website under TPUC tariff No. 1.
Need to pull your actual usage data to compare rates? See the Chattanooga Gas Company Data Access Guide →
Current Rate Schedules
Chattanooga Gas (Southern Company Gas) operates under Gas Tariff TPUC No. 1, with rates adjusted through an Annual Review Mechanism approved by the Tennessee Public Utility Commission — the latest $3.8M adjustment took effect September 1, 2025 (about +5.7% for a typical residential bill). Commercial classes scale from C-1 small C&I through C-2 medium, F-1 large-volume firm, I-1 interruptible, and T-1/T-2/T-3 transportation services for customers buying their own gas supply. Sales rates carry a Purchased Gas Adjustment (PGA) that passes commodity costs through monthly; base rates are seasonal (winter November-April, summer May-October).
Effective: September 1, 2025 · Full Tariff Book →
| Schedule | Type | Applicability | Structure | Rate |
|---|---|---|---|---|
| C-1 — Small Commercial & Industrial General Service | commercial | Commercial or industrial customers consuming up to roughly 4,000 therms annually through a single delivery point. | Seasonal base use charge (filed at approximately $53.80/bill winter, $46.40 summer per the recent ARM notice) plus a flat per-therm distribution rate (~$0.32/therm winter, ~$0.25/therm summer) and the PGA gas cost rider. See the TPUC No. 1 tariff for current rates. | ~$0.25-$0.32/therm distribution + PGA |
| C-2 — Medium Commercial & Industrial General Service | commercial | Mid-size C&I customers exceeding the C-1 annual volume threshold; restaurants, hotels, institutional kitchens, light manufacturing. | Seasonal base use charge and declining per-therm distribution blocks, plus PGA. An air-conditioning rate rider applies to summer gas A/C load. See tariff for current rates. | — |
| F-1 — Large Volume Firm Sales Service | industrial | Large-volume C&I customers requiring firm (non-interruptible) gas supply, typically under contract. | Contract-based firm sales service with customer charge, demand-based components, and commodity charges plus PGA. Pairs with T-2/T-3 transportation alternatives. See tariff for current rates. | — |
| I-1 — Commercial & Industrial Interruptible Service | industrial | Large C&I customers with alternate fuel capability willing to accept curtailment; minimum interruptible requirement around 100 Dth/day above any firm purchases. | Base use charge of roughly $518/month with declining commodity blocks (filed near $1.40/Dth for the first 1,500 Dth down to ~$0.42/Dth over 15,000 Dth per the recent ARM notice) plus gas cost. Customers may stack firm C-1/C-2/F-1 volumes with interruptible volumes through a single meter. See tariff for current rates. | ~$0.42-$1.40/Dth distribution by block |
| T-1 / T-2 / T-3 — Transportation Services | industrial | Eligible large-volume customers buying gas from third-party marketers and paying Chattanooga Gas for delivery only; T-2 adds firm gas supply backup, T-3 serves lower-volume transport. | Customer charge (~$518/month on T-1/T-2) with declining per-Dth transportation blocks mirroring I-1, a system capacity charge (~$2.40/Dth filed), and on T-2 a demand charge (~$10.80 per demand unit) for firm backup. Service requires an annual Transportation Service Agreement. See tariff for current rates. | —+ T-2: ~$10.80/demand unit for firm backup |
Rate Recommendations by Use Case
Industrial plant with large, steady gas load
Manufacturers and process loads above ~100,000 therms/year should evaluate transportation service — buying gas from a marketer and paying Chattanooga Gas only for delivery.
Transportation unbundles the commodity from delivery, letting large users shop supply competitively instead of taking the PGA. T-2's firm backup option hedges curtailment risk for processes that can't stop; the declining Dth blocks reward volume.
- Get competing quotes from gas marketers before each contract year — commodity is the largest bill component.
- Match your Maximum Daily Quantity (MDQ) and nominations to actual burn to avoid imbalance penalties.
- If your process can't tolerate interruption, price T-2's demand charge against the cost of a curtailment event.
Facility with dual-fuel or curtailable load
Asphalt plants, boilers with fuel-oil backup, and seasonal process loads can take I-1 interruptible service at distribution rates well below firm service.
I-1's declining blocks (down to roughly $0.42/Dth over 15,000 Dth) trade price for curtailment exposure on peak winter days. Customers can blend firm C-1/C-2/F-1 base volumes with interruptible swing volumes through one meter.
- Maintain and test alternate fuel capability — curtailment can come on short notice in cold snaps.
- Set the firm/interruptible split deliberately: firm covers must-run load, interruptible covers swing.
- Maintain at least the ~100 Dth/day interruptible minimum to stay eligible.
Restaurant, hotel, or small commercial kitchen
Small C&I accounts under ~4,000 therms/year take C-1 with seasonal base charges and flat per-therm pricing; growing accounts graduate to C-2.
On sales service the PGA commodity rider dominates winter bills, so efficiency and load management matter more than schedule choice at this size. The seasonal rate design makes winter therms meaningfully more expensive than summer.
- Service boilers and water heaters before heating season — winter therms carry the highest rates.
- If annual usage approaches the C-1 ceiling, ask Chattanooga Gas for a C-2 comparison.
- Gas A/C equipment is billed under a separate summer A/C rate rider — verify it's applied correctly.
Historical Rate Trends
Chattanooga Gas operates under TPUC tariff No. 1, effective November 1, 2018. The most recent annual rate review took effect September 1, 2025.
November 1, 2018
TPUC tariff No. 1 issued October 22, 2018, effective November 1, 2018.
Baseline tariffSeptember 1, 2025
Latest annual rate review approved, rates effective September 1, 2025.
Annual rate review adjustmentOverall trend: increasing
Cost Optimization Strategies
As a gas-only LDC with seasonal rates, a monthly PGA rider, and a full menu of interruptible and transportation schedules, Chattanooga Gas offers more structural savings levers than most utilities its size — the biggest wins come from unbundling supply, electing interruptible service where feasible, and managing winter consumption.
Transportation service election
For: Large-volume C&I customers (~100,000+ therms/year)
Customers above the eligibility threshold can buy gas competitively from marketers under T-1/T-2/T-3 and pay Chattanooga Gas only for delivery, replacing the PGA with negotiated commodity pricing. Annual Transportation Service Agreements and MDQ management are required.
Interruptible rate election
For: Customers with fuel oil/propane backup or curtailable processes
Dual-fuel and curtailable loads qualify for I-1's declining-block distribution rates, far below firm service at volume. The trade is curtailment exposure on peak days — priced correctly, the discount funds alternate-fuel readiness.
Seasonal load management
For: All commercial and industrial customers
Base charges and per-therm rates step up in winter (November-April). Pre-season boiler tune-ups, steam trap surveys, heat recovery, and setpoint discipline cut consumption exactly when therms cost the most.
Firm/interruptible volume blending
For: Large customers with mixed critical and flexible gas loads
The tariff allows stacking firm C-1/C-2/F-1 volumes with I-1 interruptible volumes through one meter at an agreed daily firm quantity. Sizing the firm block to true must-run load and letting swing volumes ride the cheaper interruptible rate optimizes the blend.
PGA and ARM tracking
For: All customers; essential for budget owners on sales service
Bills move with the monthly Purchased Gas Adjustment and annual TPUC-approved ARM rate changes (latest effective September 1, 2025). Trend the PGA separately from base rates to budget accurately and to time a transportation-service business case.
To implement these strategies, you need your 15-minute interval data. Learn how to download Chattanooga Gas Company interval data →
Frequently Asked Questions
How do commercial customers get usage data from Chattanooga Gas programmatically?▾
Enroll in the EDI trading partner program. EDI 814 Customer Historical Usage Requests return monthly consumption data in ANSI X12 format, EDI 810 delivers electronic bills, and EDI 820 handles payments. Start by emailing edimsg@aglresources.com to get the enrollment package, sign the NAESB EDI Trading Partner Agreement, and complete message testing.
Does Chattanooga Gas provide interval (sub-hourly) gas data?▾
No. The utility runs AMR metering with monthly reads only — there is no 15- or 30-minute interval data for customers or third parties. The My Account portal shows monthly usage with a 13-month comparison; EDI 814 likewise returns monthly history. Special requests go to 866.643.4168.
How can an energy consultant access a customer's Chattanooga Gas data?▾
Through EDI with customer authorization. Obtain a signed authorization, register as a trading partner via edimsg@aglresources.com with your customer list, execute the NAESB agreement, and configure VAN or direct transmission. Once tested and activated, you can pull monthly usage via EDI 814 and receive bills via EDI 810 for each authorized account.
Does Chattanooga Gas support Green Button or a public API?▾
No. There is no Green Button DMD/CMD, ESPI support, REST API, or developer portal — typical for a gas-only LDC of this size. EDI is the only programmatic channel; the portal offers PDF bills without CSV export.
Is Chattanooga Gas the same as EPB Chattanooga?▾
No. EPB is Chattanooga's municipal electric (and fiber) utility, while Chattanooga Gas Company is the investor-owned natural gas distributor (a Southern Company Gas subsidiary) serving Hamilton and Bradley counties. Facilities in Chattanooga typically deal with both: EPB for electricity and Chattanooga Gas for natural gas.
Where are Chattanooga Gas rates published?▾
Business pricing and rate plans are published at https://www.chattanoogagas.com/business/pricing-and-rate-plans.html under TPUC tariff No. 1 (effective November 1, 2018). The latest annual rate review took effect September 1, 2025; the Tennessee Public Utility Commission regulates all rates.
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