How to Read a Utility Rate Case: Rate Base, ROE and the Bill

To read a utility rate case, start with the revenue requirement the utility is asking for, then break it into its parts: operating costs, depreciation, taxes and the return on rate base. Most of the argument, and most of the shareholders' money, sits in three numbers: the size of the rate base, the allowed return on equity, and the share of the rate base financed with equity. Then translate the request into a monthly residential bill and read what the commission staff, consumer advocate and large customers say about it.

The stakes are easiest to see in California. On 8 November 2018 a hook on a 1921 transmission tower owned by Pacific Gas and Electric failed, and the Camp Fire destroyed the town of Paradise and killed 85 people. PG&E filed for bankruptcy in January 2019 and emerged in July 2020. Through all of it, its rate base, the capital on which it is allowed to earn a return, never stopped growing. What it had to win back was the right to earn on it. By 2024 PG&E's bills were roughly twice the national average (reported), and on 22 October 2026 it cut $2 billion from its 2027 capital plan (company). A rate case is where that tension between investment and affordability is decided.

What is a utility rate case?

A regulated electric utility holds a monopoly over the wires in its territory, and often over generation too. In return it accepts an obligation to serve every customer and lets a state public utility commission decide what it may charge. The regulator does not set a profit. It sets a revenue requirement, and the rate case is the proceeding in which the utility asks for a new one.

A general rate case typically runs 9 to 12 months:

1. Filing. The utility files testimony on its test-year costs, rate base, cost of capital (usually asking for an ROE well above its last award), cost of service and proposed tariffs.
2. Discovery and intervention. Commission staff, the state consumer advocate, industrial customers, environmental groups and, increasingly, data-center developers file data requests and opposing testimony.
3. Settlement or hearing. Most cases settle at least partly; the rest go to hearings before an administrative law judge.
4. Order. The commission decides revenue, ROE, equity ratio and rate design. Awards usually come in well below the request.
5. Compliance and appeal. Tariffs are filed, and parties can seek rehearing and appeal.

The book's chapter on utilities and grids explains why this structure makes a utility's management want to invest.

Step 1: Break down the revenue requirement

Every cost-of-service rate case argues about the terms of one equation:

Revenue requirement = operating and maintenance expense + depreciation + taxes + (rate base × allowed rate of return)

Ask how much of the requested increase comes from each line: rate-base growth, a higher return, depreciation, operating costs, fuel, or storm and wildfire recovery. The answer tells you whether the case is about investment, cost control or a one-off event.

Step 2: Understand what is in the rate base

Rate base is gross plant in service, less accumulated depreciation and accumulated deferred income taxes, plus working capital, and in some states construction work in progress. The return is the part shareholders care about.

A worked number from the book's research shows the scale. With a 50% equity ratio, a 9.8% allowed ROE and a 5.0% cost of debt, the after-tax weighted return is 7.4%. Grossing up the equity return for a 21% federal tax rate gives a pre-tax return of about 8.7% of rate base that customers pay each year. On $20 billion of rate base that is about $1.74 billion a year, of which about $0.98 billion is the shareholders' allowed net income (stylized).

Two tests decide whether money reaches rate base. Prudence asks whether a decision was reasonable given what the utility knew at the time. Used and useful asks whether the asset actually serves customers. Mississippi's regulators refused to put most of Southern Company's Kemper County plant into rates after its cost rose from about $2.4 billion to about $7.5 billion (reported); its gasifiers were abandoned in June 2017. Laws that let utilities recover financing costs during construction, such as Georgia's for the Vogtle reactors, move construction risk onto customers. Our case study on Vogtle's cost overrun shows how that played out.

Check how much of the requested rate base is new capital not yet in service, and whether any of it carries a history of overruns.

Step 3: Weigh the ROE against the equity ratio

The allowed return on equity draws the headlines. US authorized electric ROEs averaged about 9.74% in 2024, about 9.77% in 2025 and about 9.79% in the first half of 2026 (S&P Global Regulatory Research Associates, reported). They have barely moved even though Treasury yields rose from below 1% in 2020 to above 4% in 2023–26.

The equity ratio is the underrated number. In the research's stylized example, raising the equity share from 50% to 55% on about $33 billion of rate base adds about $122 million a year to customer cost, more than a half-point ROE increase, which adds about $105 million. Rate cases are argued over tenths of a percentage point for this reason. In the book's stylized example of $15 billion of capital, moving the allowed ROE from 9.8% to 10.5% changes the residential bill by about 60 cents a month and the utility's earnings by about $55 million a year.

Step 4: Find the riders and the regulatory lag

The allowed ROE is a ceiling in practice, not a promise. Utilities earn less than allowed when costs rise between rate cases or sales fall short of forecast. This regulatory lag can cost a percentage point or more a year when rate base grows quickly on a historical test year: in a stylized case, an allowed 9.8% becomes an earned 8.8–9.0% when rate base grows about 8% a year.

Utilities reduce lag with:

• Forecast test years, used in California, New York and Wisconsin.
• Riders and trackers, separate surcharges that recover specific capital, such as storm hardening or transmission, between rate cases.
• Formula rates with annual true-ups, standard for FERC-regulated transmission.
• Multi-year rate plans with pre-set increases.
• Decoupling, which separates revenue from sales so efficiency or rooftop solar does not cut recovery of fixed costs.

Add up what is recovered outside base rates. A modest base-rate request can hide large rider balances.

Step 5: Translate capital into the monthly bill

This is the step most readers skip and the one regulators care about most. The book works a stylized example: capital financed 52% with equity at a 10% allowed return and 48% with debt at 5%, depreciated over 40 years, with residential customers, 4.5 million of them, allocated 45% of the cost.

A $15 billion undergrounding program adds about $780 million a year of earnings at no commodity risk, and about $15 a month to every residential bill for years. PG&E's undergrounding plans moved from about 10,000 miles announced in 2021 to a 10-year plan of about 5,000 miles filed on 1 October 2026 (company), the clearest example of a spending program cut to fit the bill. Compare the result with inflation and with neighboring utilities. The US average residential price was about 17.3 cents per kWh in 2025, and the EIA projected about 18.0–18.2 cents for 2026 (reported).

Step 6: Test the load forecast and who carries it

For most of the two decades to 2022, US electricity demand was nearly flat. Data centers changed that. Dominion Energy reported a data-center pipeline of about 54 GW in northern Virginia, with about 12 GW under signed service agreements, in the third quarter of 2026. New load can lower everyone's rates if it pays its share of fixed costs, or raise them if the utility builds for load that never arrives.

Look for a large-load tariff. The common elements are a size threshold of roughly 25–100 MW, a minimum demand charge of about 60–90% of contracted demand (AEP Ohio's roughly 85% is the most cited), terms of about 10–20 years, exit fees and collateral (reported ranges). In a stylized 500 MW campus that leaves after eight years, an 85% minimum over 12 years roughly halves the stranded cost left with other customers. In markets with capacity auctions, data-center load also reaches bills through wholesale prices, as our explainer on the PJM capacity auction shows.

Step 7: Read the regulator and the politics

A utility's route to market is its franchise, so its licence to operate matters more than for almost any other energy business. Commissioners are appointed by governors in most states but elected in about ten, including Georgia, where two incumbents lost in November 2025 in an election fought largely over bills and Vogtle (reported). Check recent decisions on prudence and disallowance, the political temperature on affordability, and anything in the record, such as a safety finding, that could color the commission's view.

Mergers raise the same questions. On 18 May 2026 NextEra Energy agreed to buy Dominion Energy in an all-stock deal of about $66.8 billion, offering about $2.25 billion of bill credits; Virginia's commission was to begin hearings in November 2026 (company filings). Ask whether bill credits outweigh what the buyer expects to recover elsewhere.

A rate-case reading checklist

• What revenue increase is requested, and how much is rate-base growth, return, depreciation, operating cost, fuel or event recovery?
• What rate base is the utility asking to earn on, and how much is not yet in service?
• What ROE and equity ratio does it request, against recent awards and the national average?
• How far apart are the utility, staff and consumer advocate, and how have past settlements landed?
• What riders, trackers and deferred balances sit outside base rates?
• How does the typical residential bill change, compared with inflation and neighbors?
• How do large new loads pay for the grid built for them?
• Is any safety finding, audit or controversy likely to color the decision?

This guide is educational. It describes how analysts read rate cases and is not a recommendation about any security.

How rate cases fit the power equation

The Power Equation holds that an energy company creates durable value only when four factors hold at once: supply at a cost the market will pay, a route to market, capital matched to the asset, and a licence to operate. A regulated utility's route to market and matched capital are built into its franchise. What can fail is the licence, which is not a moat the utility owns but a condition it keeps meeting, every rate case, every fire season and every bill. PG&E's monopoly and cost of capital were never in question after the Camp Fire; its permission to keep earning on them was. To see how utilities compare with other links in the chain, read our guide to how the energy industry makes money, and for the difference between wires-only and integrated states, our comparison of regulated vs deregulated electricity markets. The book's study of electric utilities, grids and rate regulation and the PG&E profile hold the detail.

The takeaway

A rate case is an argument about one equation, and most of the money turns on the rate base, the allowed ROE and the equity ratio. Read the request line by line, find what is recovered outside base rates, and translate the capital plan into a monthly bill, because that is the number regulators and voters react to. Then test the load forecast and read the politics, since a utility earns only as long as its commission and its customers accept the bill. Chapter 7 of The Power Equation explains why affordability, not demand or technology, is the binding constraint on a regulated utility.