Taunton Municipal Lighting Plant (TMLP) Rate Selection Guide
Taunton Municipal Lighting Plant (TMLP) is a Massachusetts municipal light plant founded in 1897 serving roughly 40,700 customers across six southeastern Massachusetts communities. C&I customers access bills and usage analysis through portal.tmlp.com, and an AMI deployment (completed ~2022) puts interval data within reach — but Green Button, third-party programs, and APIs are not documented, so data access beyond the portal runs through direct requests to customer service.
Market Overview
Massachusetts municipal light plant: the state's retail market is restructured for IOUs, but MLPs like TMLP remain bundled monopoly providers in their territories. TMLP participates in ISO New England as a load distribution company.
Need to pull your actual usage data to compare rates? See the Taunton Municipal Lighting Plant (TMLP) Data Access Guide →
Current Rate Schedules
Taunton Municipal Lighting Plant (TMLP) is a Massachusetts municipal utility serving 38,000+ customers across Taunton and surrounding towns, with rates set by its own commission after an annual cost-of-service evaluation rather than by the DPU. Since April 2023 TMLP unbundles every bill into delivery components (distribution, transmission, transition) and a supplier generation charge. Commercial customers ladder up from General Service (under 15,000 kWh/month, energy-only) to Secondary Light & Power (demand-billed) to General Service Primary for loads above 150 kVA, where customers supply their own transformation and — on the network variant — pay four separate coincident-peak demand charges tied to ISO-NE and local peaks. Posted figures below are from TMLP's published commercial rate sheets; TMLP adjusts rates as its annual cost-of-service review requires, so verify against the current rate PDFs.
Effective: April 1, 2023 · Full Tariff Book →
| Schedule | Type | Applicability | Structure | Rate |
|---|---|---|---|---|
| Rates 21/27 – General Service | commercial | Small professional, mercantile, commercial, school, church, hospital, public building, and light industrial accounts using under 15,000 kWh/month | $34.37/month service charge plus unbundled per-kWh charges: distribution $0.04773, transition $0.05023, transmission $0.02158, and generation $0.05873 — $0.17827/kWh total; no demand charge | $0.17827/kWh all-in |
| Rates 37/38/39 – Secondary Light and Power Service | commercial | General commercial and industrial service for lighting, power, refrigeration, and heating at secondary voltage | $206.38/month service charge; energy at $0.09440/kWh total ($0.02693 delivery + $0.06747 generation); demand at $18.85/kW total (distribution $7.31 + transition $4.53 + transmission $7.01) on the higher of the current month's or prior June-August's highest 15-minute kW; $394.88 minimum including 10 kW minimum demand | $0.09440/kWh+ $18.85/kW (15-min, summer ratchet) |
| Rate 31 – General Service Primary | industrial | Industrial or commercial loads exceeding 150 kVA, metered at primary voltage; customer supplies all transformation and regulating equipment | $907.76/month service charge; hours-use energy pricing (first 300 hours $0.09672/kWh total, excess $0.08268/kWh total); demand at $17.76/kVA total with a summer-month ratchet; $3,571.76 minimum bill including 150 kVA minimum demand | $0.083–$0.097/kWh by hours use+ $17.76/kVA (15-min, summer ratchet) |
| General Service Primary – Network (coincident peak) | industrial | Primary-voltage loads over 150 kVA on the network rate variant | $1,057.76/month service charge with the same hours-use energy pricing, but demand split into four separately measured billing demands: $5.33/kVA on the customer's 12-month peak (distribution + transition), $9.11/kVA on the monthly coincident network peak (transmission), $3.99/kVA FCM on the rolling ISO-NE annual coincident peak, and $0.23/kVA on the TMLP territory annual peak; $3,856.76 minimum | —+ Up to ~$18.66/kVA across four coincident-peak components |
Rate Recommendations by Use Case
Large industrial facility (>150 kVA) on the network primary rate
Manage the ISO-NE and network coincident peaks — on this rate, when you peak matters more than how high you peak.
The network variant bills $9.11/kVA on the monthly network coincident peak and $3.99/kVA FCM on the rolling ISO-NE annual peak hour. Facilities that curtail during predicted ISO-NE peak hours (typically hot summer weekday late afternoons) can avoid an entire year of FCM charges, and monthly network-peak avoidance compounds on top.
- Subscribe to an ISO-NE peak prediction service and pre-plan curtailment for likely annual peak days
- Curtail or shift load during predicted monthly network peak hours, not just your own peak
- Compare the standard Rate 31 versus the network variant annually — the better choice depends on your ability to dodge coincident peaks
Mid-size commercial or industrial building at secondary voltage
Take Secondary Light & Power and manage the summer ratchet — one hot July afternoon can set your demand charge for a year.
Billing demand is the higher of the current month and the preceding June-August peak, so a single 15-minute summer excursion ratchets the $18.85/kW charge across subsequent months. Summer peak control is worth far more here than at non-ratcheted utilities.
- Pre-cool buildings and stage chillers on forecast 90°F+ days to cap the June-August peak
- Verify each bill's demand against your own metering — ratchet billing errors persist for months
- Use TMLP's Large Commercial Rate Calculator to model demand scenarios
Small storefront, office, or restaurant under 15,000 kWh/month
Stay on General Service (Rates 21/27) and treat the flat $0.178/kWh all-in rate as a pure efficiency target.
GS has no demand charge, so every kWh saved returns the full unbundled rate. Accounts approaching 15,000 kWh/month should model the move to Secondary Light & Power, which cuts the energy rate nearly in half but adds an $18.85/kW demand charge — favorable only at high load factor.
- Track monthly kWh against the 15,000 threshold
- Run the Small vs. Large Commercial calculators before any rate change request — TMLP holds you to a rate for 12 months
- Prioritize LED and refrigeration upgrades at the full $0.178/kWh value
Multi-building campus or municipal portfolio in TMLP territory
Audit rate assignments across all meters annually — TMLP's terms entitle every customer to request the lowest applicable rate each year.
TMLP's General Terms and Conditions state every customer may request service under the lowest rate applicable each calendar year, with rate changes locked for 12 months. Portfolios with varied load shapes frequently have meters straddling rate-class boundaries where reassignment saves money at zero cost.
- Compare each meter's usage and demand against the GS/Secondary/Primary boundaries every year
- Submit written rate-change requests when usage materially changes mid-year
- Use the April 2023 unbundled bill components to see exactly which charges dominate each meter
Cost Optimization Strategies
TMLP's rate design concentrates savings in three mechanisms: the summer demand ratchet on secondary service, the four coincident-peak demand charges on the network primary rate, and the steep rate-class boundaries at 15,000 kWh and 150 kVA. Since TMLP unbundled its bill components in April 2023, customers can finally see which of the distribution, transition, transmission, and generation lines their load actually drives — and target the right one.
Control the June-August demand ratchet
For: Rates 37/38/39 and Rate 31 customers
Secondary Light & Power and Rate 31 bill the higher of the current month's peak and the prior summer's peak, so the June-August window sets demand charges for the following year. Pre-cooling, chiller staging, and demand limiting during summer heat events protect twelve months of bills at $17.76-$18.85 per kW/kVA.
Dodge ISO-NE and network coincident peaks
For: General Service Primary – Network customers
Network primary customers pay $9.11/kVA on the monthly network coincident peak and $3.99/kVA FCM on the ISO-NE annual peak hour. Predictive curtailment during the handful of likely peak hours per year — hot weekday afternoons, 4-6 PM — directly reduces these charges without affecting total consumption.
Optimize rate class at the boundaries
For: Commercial accounts near 15,000 kWh/month or 150 kVA
The jump from GS ($0.178/kWh, no demand) to Secondary L&P ($0.094/kWh + $18.85/kW) flips economics with load factor: high-load-factor accounts save on the demand rate, peaky accounts do not. TMLP's terms let customers request the lowest applicable rate annually — run the comparison with the utility's own online calculators.
Exploit hours-use energy pricing on primary rates
For: Primary-voltage industrial customers
Rate 31 prices the first 300 hours-use of energy higher ($0.09672/kWh) than excess consumption ($0.08268/kWh), rewarding high load factor. Flattening production schedules to raise hours-use pushes more kWh into the cheaper block while simultaneously reducing the demand-to-energy ratio.
Validate unbundled bill components
For: All C&I customers
Since April 2023, TMLP invoices break out distribution, transition, transmission, and generation charges separately. Reconcile each component against the published rate sheets monthly — unbundling makes errors visible, and the transition charge in particular varies by class and is easy to misapply.
To implement these strategies, you need your 15-minute interval data. Learn how to download Taunton Municipal Lighting Plant (TMLP) interval data →
Frequently Asked Questions
How do commercial customers access TMLP billing and usage data?▾
Register at portal.tmlp.com using your most recent bill. The portal provides current and historical bills (PDF), payment history, unbundled rate components, and an analyze-and-download electricity usage function. CSV export is unconfirmed — call 508-824-6976 to verify download formats for your account.
Does TMLP provide interval meter data?▾
Likely yes for newer meters: TMLP completed an AMR/AMI deployment around 2022, and Massachusetts standards point to 15- or 30-minute granularity. The exact granularity and download format are not published — ask customer service specifically about interval meter data download options before designing an analytics workflow around it.
Can a consultant or aggregator access TMLP data for a customer?▾
Only through a manual process. There is no Share My Data portal, API, or aggregator integration. The customer signs a written authorization specifying the third party, data types, and duration; the third party submits it to Customer Service (508-824-6976) with the account number. Data arrives as PDF bills by email or via portal downloads the customer shares.
Does TMLP support Green Button or EDI?▾
Green Button: no — neither Download My Data nor Connect My Data is documented, and TMLP is not a Green Button Alliance member. EDI: possibly for suppliers under Massachusetts EBT standards (EDI 4010), but no enrollment process is published; contact the Administrative Offices at 508-824-5844 for trading partner information.
What does Nectar's roadmap support level mean for TMLP accounts?▾
TMLP is on Nectar's roadmap: automated ingestion is planned but not yet productized. Today, Nectar works with TMLP data via customer-downloaded portal PDFs and usage exports or authorization-based manual requests while native support is built.
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