Mason County PUD No. 3 Rate Selection Guide
Mason County PUD No. 3 is a public utility district serving roughly 36,400 electric customers across 600 square miles of Mason County, Washington. The PUD runs NISC iVUE with the SmartHub portal and a full AMI smart meter deployment, and supports Green Button Download My Data with up to 14 months of ESPI XML exports — though it offers no Connect My Data, EDI program, or public API.
Market Overview
Washington has no retail electric choice. Mason PUD 3 sets its own rates as a public utility district; rate and fee schedules are published as PDFs on its website, and service rules live in the website Document Archive. Data access is governed by customer service policy rather than tariff.
Need to pull your actual usage data to compare rates? See the Mason County PUD No. 3 Data Access Guide →
Current Rate Schedules
Mason PUD 3's commissioner-set rates pair low BPA hydropower energy prices (residential averages around 8.5¢/kWh) with a daily system charge — a 'ready to serve' fee dating to 1978 that spreads fixed costs across the district's many seasonal accounts (over 25% vacation homes). Commercial service splits at 15,000 kWh/month or 50 kW: below both thresholds is Small General Service Schedule 20, above either is Large General Service Schedule 21 with demand billing. Specialty schedules cover cannabis production (Schedule 24, ineligible for BPA-funded conservation), public EV charging up to 0.5 MW (Schedule 27), New or Expanding Large Loads of 0.5 aMW/1 MW+ (Schedule 50, contract required), and legacy Large Industrial primary-voltage service (Schedule 61). Bills also carry Washington Public Utility Tax (3.8734%), PUD Privilege Tax (2.14%), a Shelton city tax (6%) inside city limits, a CETA low-income surcharge, and — January through October 2026 — a Temporary BPA Power Adjustment (~$1.63/month). Per-kWh and demand figures are published in schedule PDFs — see tariff for current rates.
Effective: January 1, 2026 · Full Tariff Book →
| Schedule | Type | Applicability | Structure | Rate |
|---|---|---|---|---|
| Schedule 20 – Small General Service (Commercial) | commercial | Commercial accounts, schools, churches, public agencies, and three-phase well services using under 15,000 kWh in any month with demand of 50 kW or less in all months | Daily system charge plus energy charges; no demand billing — see tariff PDF for current rates | — |
| Schedule 21 – Large General Service (Commercial) | commercial | Commercial and institutional consumers exceeding 15,000 kWh in any month or 50 kW demand in any month | Daily system charge, energy charges, and demand billing — see tariff PDF for current rates | — |
| Schedule 24 – Cannabis General Service | commercial | All services producing or processing cannabis under Washington law | Dedicated rate schedule; customers are ineligible for BPA-funded conservation or financial assistance — see tariff PDF for current rates | — |
| Schedule 27 – Public Electric Vehicle Chargers | ev | Separately metered public EV charging equipment with total connected load up to 0.5 MW; optional election with a 12-month re-entry lockout after exit | EV-specific rate designed for charging load profiles; not available for seasonally disconnected loads — see tariff PDF for current rates | — |
| Schedule 50 – New or Expanding Large Load (NELL) | industrial | New facilities or expansions adding 0.5 aMW or 1 MW+ of demand over any consecutive 12 months — data centers, large industrial, and similar loads | Contract-based service required before delivery begins; NELL designation persists even if load later decreases — see tariff and contract terms | — |
| Schedule 61 – Large Industrial (Legacy) | industrial | Existing industrial consumers at 12,470 V primary voltage with demand of at least 1,000 kW, connected at a distribution substation; closed to new customers | Primary-voltage demand and energy billing — see tariff PDF for current rates | — |
Rate Recommendations by Use Case
Standardized usage data collection for analysis
Pull Green Button DMD exports for machine-readable interval usage instead of scraping portal views.
Green Button DMD is the only sanctioned machine-readable export at PUD 3 — ESPI XML imports cleanly into energy management and benchmarking tools.
- Download in 14-month windows and stitch files for longer history
- Automate parsing of the NAESB REQ.21-compliant XML
- Re-request periodically since there is no automated feed
Third-party energy management for C&I accounts
Combine a signed customer authorization with Green Button file sharing and manual utility requests.
PUD 3 has no aggregator program or CMD, so file-based Green Button sharing plus authorized manual requests is the workable third-party path.
- Have clients sign a data release before contacting (360) 426-8255
- Specify data type, period, and desired format in each request
- Budget 5-10 business days for manual extract turnaround
Automated integration for energy software platforms
Plan around manual workflows today and monitor for NISC platform upgrades.
There is no public API, and reverse-engineered SmartHub endpoints are unsupported; NISC's DERMS APIs and potential CMD enablement are the realistic future paths.
- Contact NISC directly about custom integration or data export partnerships
- Check annually whether PUD 3 enables Green Button Connect My Data
- Ask about case-by-case EDI if serving many PUD 3 accounts
Cost Optimization Strategies
Mason PUD 3's BPA hydropower keeps energy cheap, so the optimization levers are structural: the 15,000 kWh / 50 kW boundary between Schedules 20 and 21, demand control on large general service, schedule election for EV charging, and the tax-and-surcharge stack (state taxes, CETA surcharge, and the 2026 Temporary BPA Power Adjustment) that rides on top of every bill.
Manage the Schedule 20/21 boundary
For: Commercial accounts operating near 15,000 kWh/month or 50 kW
A single month over 15,000 kWh or 50 kW moves an account from Small to Large General Service with demand billing. Accounts near the threshold should track monthly usage through SmartHub and smooth one-off spikes (seasonal startups, special events) that would trigger reclassification.
Demand peak control on Schedule 21
For: Schedule 21 commercial and institutional accounts
Large General Service bills demand on the monthly peak. Sequence HVAC, kitchen, shop, and well-pump loads so they don't stack into the same interval — SmartHub's daily kWh data plus a targeted interval-data request from the PUD identifies the peak-setting hours.
Elect Schedule 27 for public EV charging
For: Businesses, agencies, and hosts deploying public EV charging
Separately metered public chargers up to 0.5 MW can opt into the EV-specific schedule, isolating spiky charging load from the host building's demand billing. The election is optional but carries a 12-month lockout after exit — model a year of charging utilization before switching.
BPA conservation incentives and efficiency
For: All commercial classes except Schedule 24 cannabis accounts
As a BPA full-requirements utility, PUD 3 channels BPA-funded conservation programs (lighting, HVAC, weatherization, motors) to commercial customers — note cannabis customers on Schedule 24 are excluded by federal rules. Efficiency also trims the percentage-based state taxes and surcharges that scale with the bill.
Plan large loads around NELL terms
For: Expanding industrial facilities, data centers, and large new commercial loads
Growth that adds 0.5 aMW or 1 MW of demand within 12 months triggers Schedule 50 contract service — and the NELL designation is permanent even if load later shrinks. Phase expansions deliberately and engage PUD 3 early; once designated, terms are contractual rather than tariff-default.
To implement these strategies, you need your 15-minute interval data. Learn how to download Mason County PUD No. 3 interval data →
Frequently Asked Questions
Does Mason PUD 3 support Green Button exports for C&I accounts?▾
Yes — Green Button Download My Data is live in SmartHub. From the My Usage tab, download up to 14 months of usage as zipped ESPI XML (NAESB REQ.21 compliant) and import it into energy management or benchmarking tools. Connect My Data (automated token-based sharing) is not enabled.
What interval granularity does Mason PUD 3 provide?▾
Daily kWh is the documented granularity in SmartHub. The AMI meters can collect finer intervals, and Green Button exports contain data at the meter's available resolution, but 15/30-minute availability is not publicly confirmed — call (360) 426-8255 to verify for a specific account.
How do consultants or aggregators get authorized access to PUD 3 customer data?▾
There is no aggregator program or authorization portal. Get a signed customer data release, then contact PUD 3 at (360) 426-8255 (M-Th, 7 AM-5:30 PM PT) specifying data type, period, and format. Extracts arrive by email or paper in roughly 5-10 business days; the simplest path is having the customer share Green Button XML files directly.
Does Mason PUD 3 offer EDI or a public API?▾
No public EDI trading partner program or API exists. EDI may be negotiable case-by-case through the billing department. Community projects have reverse-engineered the NISC SmartHub JSON API for 15-minute data pulls, but that approach is unsupported and at the user's own risk — production integrations should go through NISC or sanctioned file-based exports.
How far back can usage history be pulled from Mason PUD 3?▾
Green Button DMD allows up to 14 months per request — shorter than the 3+ years some large utilities offer. SmartHub shows daily data for current and prior billing periods; for longer billing history, submit a customer-authorized manual request to the utility.
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