Your 2050 grid statement

For scale: the state’s own plan has total electric distribution revenue rising from $2.8 billion in 2020 to $6.3 billion in 2050 for all causes, an increase of $3.5 billion (2020 dollars; paper p.30, note 38). A reference bill today is about $226 a month for 600 kWh (Eversource R-1, Greater Boston, filed rates effective Sept. 1, 2026) verified

Each line is a figure from the paper. Move a quantity and the amounts, the running bars, the bill and every chart below re-total. The small tick under each slider marks what the paper assumed.

Who pays for it

The paper did not assess who pays; it only says developers have historically paid for solar hosting and that regulators are weighing that (pp.29–30). Its low revenue case assumes developers cover half of the hosting cost.

Capital carried by ratepayers in your scenario: $27.2B

Utilities do not bill for construction. They earn a return on what they invest and recover its cost over decades. Each year’s charge is depreciation plus a return on what has not yet been paid off, plus a small carrying cost. The bars stack each five-year build, so you can see the bill grow as new plant goes in.

A yearly charge becomes a bill once it is divided over the electricity sold. Massachusetts sold 49.4 billion kWh in 2024. The state’s 2050 modeling has electrification, mostly heat pumps and electric vehicles, roughly doubling what the grid delivers. Pick a pathway; every cost above is spread over that much electricity.

Delivered electricity is the final demand shown minus 8.3 billion kWh of rooftop solar that never crosses the meter (Roadmap Table 22), over 2024 sales. The 2020 starting level (about 55 TWh) was read off the chart and is not labeled there.

The red segment is your scenario’s new-capacity charge, about 7% of a reference bill, drawn as its own add-on. The paper prices only distribution-capacity upgrades, and the distribution line is about 26% of a reference bill. It prices nothing else here: not supply, transmission, or the policy line items. It does not assess where on a bill a utility would recover the cost. The add-on is in 2021 dollars set against a bill in current dollars, so the gap in today’s dollars is somewhat larger. Shares come from Eversource’s filed R-1 rates for Greater Boston, effective Sept. 1, 2026, with Basic Service at 17.323¢ a kWh, for a 600 kWh month: one utility’s Boston-area bill, not a statewide average. verified

• Full return on 2021-dollar plant
• Inflation-adjusted return
• Your scenario

Each dot is one of 18 combinations: the paper’s three cases, the three demand pathways, and the two inflation treatments, with your rate inputs held. The bill is for 600 kWh a month, spread evenly per kWh. Real rate design assigns costs by customer class, and the paper did not assess that.

Each bar shows the total if that one input sits at its low or high end while everything else stays where you set it. A solid bar is a range the paper itself reports. An outlined bar is my judgment, because the paper gives a single value. The red line is your total.

• Range from the paper
• Range chosen by me
• Your total

• Everything already on a bill. Supply, existing delivery and transmission charges, and policy charges are not here. This is only the added cost of new local-grid capacity.
• Transmission and other grid costs. The paper prices local distribution capacity only. It says transmission upgrades will also be needed, and leaves out operating and maintenance costs, storm costs, replacing aging equipment and grid modernization (pp.25–26, 33).
• What is already in budgets. The paper did not check how much of its estimate utilities already plan to spend (p.29).
• Who pays. The paper did not assess cost allocation; regulators were weighing it (pp.29–30). Its current status is not checked here.
• Customer classes. Costs are spread evenly per kWh. Real rate design is not.
• Your actual use. Usage is held at 600 kWh a month. Homes that electrify use more electricity and less oil, gas or gasoline, so this is the added electric charge, not a household’s net energy cost.
• The dollar year. The paper is in 2021 dollars. Today’s bills are in current dollars.
• Hourly data. The paper’s load charts are images and no hourly series were published, so none are drawn here.
• The demand base. The paper used the state’s 2025/2030 plan scenario, whose published table stops at 2030. Demand for 2050 here comes from the 2020 Roadmap modeling.

The test of an independent estimate is whether it reproduces the original first. These are the paper’s figures next to this page’s, at the paper’s own settings.

Capital lines scale the paper’s published bars, so the defaults match it exactly. A revenue requirement is built year by year: each year’s spend enters service at once, depreciates in a straight line, and earns a pre-tax return on average net plant, plus a carrying cost. Deferred taxes are ignored, which overstates slightly. Bill = revenue requirement ÷ delivered kWh, for a 600 kWh household.

Sources

1. EPRI white paper for the Massachusetts Clean Energy Center, 2023, 36 pages. The copy CommonWealth Beacon obtained: linkjar.to/1a1f17fd
2. CommonWealth Beacon, “Mass. spent nearly $400K on an energy study. Three years after its completion, the state hasn’t released the results,” Oct 21, 2026: commonwealthbeacon.org
3. Massachusetts 2050 Decarbonization Roadmap, Energy Pathways technical report (Figure 11 p.43; Table 22): mass.gov
4. Clean Energy and Climate Plan for 2025 and 2030, appendices (table E.4): mass.gov
5. U.S. Energy Information Administration, Table 2.8, sales to ultimate customers by state: eia.gov
6. National Grid, Massachusetts Electric 2024 rate case order (return on equity, equity ratio): sec.gov