Rate R-3 Residential Space Heating (delivery only)
NSTAR Electric Company · effective 2026-07-01
Source
NSTAR Electric Company d/b/a Eversource Energy, Rate R-3 (M.D.P.U. No. 9), priced in M.D.P.U. No. 1-26-E 'Summary of Electric Service Delivery Rates', Part A, effective 07-01-26
Effective
2026-07-01
Structure
flat
· 1 rate period
Covers
delivery only — delivery alone. Supply is set by market price with no filed figure, so a real bill is higher. NOT comparable to a bundled rate
Transcription notes recorded when this tariff was encoded, including anything deliberately left out.
NSTAR Electric Company d/b/a Eversource Energy, Massachusetts. A SEPARATE operating company from The Connecticut Light and Power Company, which is also Eversource and files an entirely different tariff: CL&P puts delivery and supply on one sheet, NSTAR files delivery only.
Rates are built from the components filed in M.D.P.U. No. 1-26-E, 'Summary of Electric Service Delivery Rates', Part A, and each is asserted at build time against the Total Delivery column the tariff prints on the same row. The published total is a check, never the source.
M.D.P.U. No. 1 is the authority, NOT the customer-facing 'Summary of Electric Rates' PDFs published per service area. The filed R-1HP schedule (M.D.P.U. No. 85) carries no numbers at all - every line reads 'As per M.D.P.U. No. 1 as in effect from time to time' - which is what identifies No. 1 as the source.
TRAP in the customer-facing summary: it lists 'Energy Efficiency Charge $0.02292' as one of eleven components. In M.D.P.U. No. 1 that figure is a SUBTOTAL of System Benefits $0.00250 and the Energy Efficiency Reconciling Factor $0.02042, printed beside the two columns that actually add. The additive components are used here.
TWO RATE SETS, not four service areas. M.D.P.U. No. 1 groups them BOST/CAMB/SOUTH/WMA and CAPE. Greater Boston, Cambridge, South Shore and Western Massachusetts are identical on every component; Cape Cod & Martha's Vineyard differs in exactly one, the energy efficiency reconciling factor, by $0.01446/kWh. Service areas map to rate sets in data/current/nstar_service_areas.json.
Western Massachusetts - the former WMECO territory - shares the mainland rates. The customer-facing summary pages offer only the four Eastern Massachusetts areas and would have left WMA out silently.
Revenue Decoupling is the one component that varies BETWEEN schedules: R-1 $0.00539, R-3 $0.00527, R-1HP $0.00443. Copying a component list between schedules produces a rate that is wrong and still looks plausible.
EXCLUDED: Massachusetts state and local taxes.
Rate set 'cape', which is the filed grouping for: Cape Cod & Martha's Vineyard.
Not seasonal and not tiered: one delivery rate for every kWh in every month.
DELIVERY ONLY. This tariff prices what NSTAR charges to deliver electricity and excludes the cost of the electricity itself. A Massachusetts customer also pays either Basic Service or a competitive supplier. Use the matching bundled tariff for a whole bill; use this one to compare NSTAR schedules against each other, which is valid because supply is identical across all of them.
NOT ENCODED: R-2 (M.D.P.U. No. 8), R-2HP (No. 86) and R-4 (No. 10), the income-qualified assistance versions of R-1, R-1HP and R-3. They are filed in the same table and readable the same way, but this encoding cannot express eligibility, so /compare would recommend them to people who cannot have them. They belong in the CARE-style discount machinery in rategrid/care.py rather than as separate tariffs.
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Change history
The source document is fetched daily and every version is kept.
Utilities do not publish superseded rates, so this record does not exist
elsewhere once a rate changes.
No changes detected since monitoring began. The source sheet is checked daily.