Author: Taylor Warfield, Former Bain Manager and interviewer

Last Updated: September 29, 2026

 

A utilities case interview is a consulting case set in the electricity, gas, or water sector, where the client is usually a regulated monopoly that earns a set return on its approved capital investments instead of competing on price. That one fact changes how you structure the case, and this guide covers the industry economics, the case types that come up most, a full worked example, and the mistakes that sink candidates.

 

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Key Takeaways

 

Utilities cases reward candidates who understand rate base regulation, because in most utility cases profit comes from approved capital investment rather than from selling more units.

 

• A regulated utility earns a set return on approved capital, so "raise price" and "sell more" are usually dead ends

 

• The value chain splits into generation, transmission, distribution, and retail, and each piece has different economics

 

• Investor-owned electric companies plan roughly $238.8 billion of capital spending in 2026, according to Edison Electric Institute data

 

• Data center demand ended 15 years of flat US electricity consumption, which is why load growth cases are everywhere right now

 

• Four case types cover most of what firms give: load growth, rate case strategy, capital and cost programs, and reliability

 

• The math is unit conversion and simple returns, not engineering, but the units are where candidates lose points

 

What Is a Utilities Case Interview?

 

A utilities case interview is a consulting case in which the client is an electric, gas, or water utility. Because most utilities are regulated monopolies, the regulator sets prices and the utility earns a fixed percentage return on approved capital spending. That means the profit levers you would use in a retail or consumer case do not apply, and you have to reason from the regulated business model instead.

 

The case format itself is normal. You get a prompt, ask clarifying questions, lay out a structure, work through quantitative analysis, and deliver a recommendation. What changes is the content of your structure, which is the same reason an oil and gas case interview feels different from a consumer goods case even though the mechanics are identical.

 

Utilities cases show up most often at firms with dedicated power and utilities practices, and they show up disproportionately in experienced hire and industry-specialist interviews. If you applied to an energy practice or listed energy experience on your resume, assume you will get one.

 

How Does a Utility Actually Make Money?

 

A regulated utility makes money by investing capital, not by selling volume. The regulator approves a pool of assets called the rate base, sets an allowed rate of return on that rate base, and then sets customer rates high enough to recover operating costs plus that return. Selling one more kilowatt hour barely moves profit, but adding one more approved substation does.

 

This is the single most important idea in the entire topic. Every strong candidate I have interviewed in this space said some version of it in their opening structure. Every weak one started listing ways to raise price.

 

What are the four parts of the utility value chain?

 

Electricity moves through four stages, and each one has its own cost structure and competitive dynamics. Knowing which stage your client sits in tells you immediately which levers are even available. A generation-only client and a wires-only client face almost opposite problems.

 

Stage	What it does	Main cost driver	Typical case question
Generation	Produces power from gas, nuclear, coal, wind, solar, or hydro	Fuel and plant capital cost	Which plants do we build or retire
Transmission	Moves bulk power long distances at high voltage	Line and substation capital	Where do we relieve congestion
Distribution	Steps voltage down and delivers to homes and businesses	Poles, wires, and maintenance labor	How do we cut outage minutes
Retail	Bills customers and, in some states, competes for them	Customer acquisition and service	How do we reduce churn

 

In a vertically integrated utility, one company owns all four stages. In a restructured market, generation and retail are competitive while transmission and distribution stay regulated monopolies, which is why the wires business is often the only profitable part of the company.

 

How does rate base regulation work?

 

Rate base regulation is a simple formula wrapped in a slow legal process. The utility's allowed revenue equals its operating expenses plus depreciation plus its rate base multiplied by an allowed rate of return. Regulators set that return in proceedings called rate cases, and the utility cannot raise rates without one.

 

The numbers here are public and worth memorizing at a rough level. In January 2026 alone, state commissions completed eight base rate cases authorizing a net $433.8 million in additional revenue, with authorized returns on equity ranging from 9.40% in New York to 10.00% in Missouri, according to data from Regulatory Research Associates. In March 2026, the Federal Energy Regulatory Commission lowered the allowed return for New England transmission owners to 9.57% from the 10.57% level set in 2014.

 

Three consequences follow, and each one should show up somewhere in your structure. A utility has a strong incentive to invest capital, a weak incentive to cut capital, and a real risk of "regulatory lag" when costs rise faster than rates can be reset. Any recommendation that ignores the regulator is an incomplete recommendation.

 

What is the difference between regulated and deregulated utility markets?

 

In a traditionally regulated market, one vertically integrated utility owns generation, transmission, and distribution, and customers have no supplier choice. In a restructured market, generation and retail supply are opened to competition while the wires stay a monopoly. The US Environmental Protection Agency describes restructured competitive wholesale markets as covering the Northeast, Midwest, Texas, and California, with traditional regulation dominating the Southeast, Northwest, and much of the West.

 

Roughly 13 states plus Washington, D.C., allow residential customers to shop for an electricity supplier. Texas is the most fully competitive retail market in the country, with more than 100 retail electric providers selling into the ERCOT grid.

 

Ask which model applies in your very first clarifying question. It determines whether your client can price at all.

 

What Industry Numbers Should You Know Before the Interview?

 

You do not need to memorize a fact sheet, but a handful of current numbers will make your analysis sound like it came from someone who has worked in the sector. These are the figures I would want a candidate to have in their head walking into an energy practice interview.

 

Metric	Figure	Source and year
Investor-owned electric capital spending	$238.8B projected in 2026, up 17% from $204.1B in 2025	Edison Electric Institute, 2026
Five-year industry capital plan	Roughly $1.4 trillion through 2030	Edison Electric Institute, 2026
US electricity demand growth	2.1% per year over the last five years, after 15 flat years	EIA Annual Energy Outlook, 2026
2026 US generation mix	Gas 40%, nuclear 18%, coal 16%, wind 11%, solar 8%, hydro 6%	EIA Short-Term Energy Outlook, August 2026
Capacity waiting to connect to the grid	1,312 GW of generation plus 749 GW of storage across about 8,200 projects	Berkeley Lab, data through end of 2025
Number of US electric distribution utilities	About 3,000, of which 168 investor-owned utilities serve 72% of customers	EIA Annual Electric Power Industry Report, 2017

 

Two of these deserve extra attention. The EIA Annual Energy Outlook reports that after roughly 15 years of nearly flat consumption, US electricity demand has grown 2.1% per year over the last five years and is projected to keep growing through 2050. The Berkeley Lab interconnection queue data shows why supply cannot simply follow, with more than 2,000 gigawatts of generation and storage stuck waiting for grid connection studies at the end of 2025.

 

That gap between surging demand and a slow interconnection process is the core tension in almost every current utilities case. If you can name it in your opening structure, you sound like someone who reads the industry press.

 

What Are the Most Common Types of Utilities Cases?

 

Four case types cover the large majority of what firms actually give. Each one maps to real client work, which is why they recur. Recognizing the type within the first thirty seconds lets you build a tailored structure instead of a generic one.

 

Load growth and capacity planning cases

 

These are the most common utilities cases right now. A large customer, usually a data center campus or a manufacturing plant, wants hundreds of megawatts of new load, and the utility has to decide whether and how to serve it. The analysis covers new generation, transmission upgrades, timing, cost allocation, and what happens to other customers.

 

The EIA has already lowered its Texas load forecast to 6% growth in 2027, down from an earlier 14% projection, after the state paused new data center development. That volatility is exactly what makes these cases interesting: the demand may not show up.

 

Rate case and regulatory strategy cases

 

Here the client needs to file for a rate increase, or has just been denied one, and wants to know what to ask for and how to justify it. You are balancing the utility's need to recover capital against a regulator's affordability mandate and a customer base that is already seeing bills rise. These cases test whether you can reason about a stakeholder who is not a customer or a competitor.

 

Capital program and cost reduction cases

 

With capital budgets at record levels, utilities routinely ask consultants how to deliver a huge construction program on time and on budget. The work looks like a classic cost reduction case interview, with one twist. Cutting capital spending lowers future earnings, so the goal is efficiency per dollar deployed rather than a smaller budget.

 

Reliability and outage performance cases

 

Regulators track how often the lights go out and for how long, and poor performance can cost a utility money in penalties or a lower allowed return. Storm hardening, wildfire mitigation, and vegetation management all fall here. The structure is usually a cause analysis followed by an investment prioritization.

 

Two more types appear less often but are worth preparing. Competitive generation and retail energy clients bring standard market entry case interviews and asset acquisition questions.

 

Municipal and state-owned utilities produce a different flavor entirely. Their objective function is affordability and service, not shareholder return, so those cases look much closer to a public sector case interview than a corporate one.

 

How Should You Structure a Utilities Case?

 

Build your structure around the regulated business model rather than a memorized template. A generic profitability tree fails immediately here, because revenue is set by a regulator and volume growth does not translate into margin. The strongest structures I have seen follow four branches.

 

1. The asset: what capital is required, over what timeline, and what does it add to rate base
   
   
2. The recovery: will the regulator approve the spend, at what allowed return, and with what lag
   
   
3. The customer impact: what happens to bills, and can the affected class absorb the increase
   
   
4. The risk: what if demand, fuel prices, or the regulatory environment moves against us

 

That fourth branch is where most candidates leave value on the table. Utility assets last 30 to 50 years, so a wrong forecast does not cost one bad quarter, it strands a billion dollars of capital for decades.

 

Lead with a clear case interview hypothesis once you have laid out the branches, and say which branch you want to test first and why. Interviewers in energy practices care a lot about prioritization, because real utility clients cannot do everything at once. If you want to sharpen this skill fast, my case interview course covers tailored structuring in as little as 7 days.

 

What Does a Full Utilities Case Look Like?

 

Here is a worked example built the way an interviewer would run it. All figures are illustrative round numbers chosen to keep the math clean.

 

Prompt: Our client is a regulated electric utility serving 2 million customers. A technology company wants to build a data center campus in its territory that will need 500 megawatts of new load starting in four years. Should the utility serve it?

 

Step 1: Clarify before you structure

 

The questions worth asking are narrow and specific. Is the client vertically integrated or wires-only, does it have spare generation capacity today, and has the regulator signaled how it will treat large-load interconnection costs? Assume the client is vertically integrated, has no spare capacity, and operates in a traditionally regulated state.

 

Step 2: Size the load

 

Start by converting capacity into energy, because this is where candidates stumble. A 500 megawatt facility running at a 90% load factor consumes 500 multiplied by 8,760 hours multiplied by 0.90, which equals about 3.9 million megawatt hours, or 3.9 billion kilowatt hours per year.

 

For scale, if a typical home uses roughly 10,000 kilowatt hours a year, this one campus consumes about as much electricity as 390,000 households. On a customer base of 2 million, that is a 20% jump in a single connection.

 

Step 3: Build the revenue and cost picture

 

Say the utility's all-in delivered rate for very large industrial customers is 9 cents per kilowatt hour. Annual revenue is 3.9 billion multiplied by $0.09, which comes to roughly $351 million.

 

Now the cost side. Assume serving the campus requires $1.5 billion of new generation and transmission, depreciated over 30 years, with an allowed weighted return of 7% on rate base.

 

Annual cost item	Calculation	Amount
Allowed return on rate base	$1.5B x 7%	$105 million
Depreciation	$1.5B over 30 years	$50 million
Fuel	3.9B kWh x $0.04	$156 million
Operations and maintenance	Given	$20 million
Total annual cost	Sum	$331 million

 

Revenue of $351 million against cost of $331 million leaves about $20 million of annual margin, or under 6% of revenue. That is thin, and thin margins are the signal to start stress-testing assumptions rather than to declare victory.

 

Step 4: Find the real risk

 

The asset lasts 30 years. The customer might not. If the data center shuts down after 8 years, the utility has depreciated only $400 million of the $1.5 billion, leaving $1.1 billion of rate base that has to be recovered from the remaining 2 million customers.

 

Spread across those customers, that is roughly $550 per household of stranded cost, which is the kind of number that ends careers at a public utility commission. The economics of the deal are acceptable. The asymmetry of the risk is not.

 

Step 5: Recommend with the risk built in

 

The answer is to serve the load, but only under a long-term contract that shifts the stranded-asset risk to the customer who created it. Ask for a 20-year minimum take commitment, upfront contribution toward interconnection costs, and collateral or a parent guarantee. Then confirm the structure with the regulator before signing, so cost recovery is not litigated after the fact.

 

Notice what the recommendation does not say. It does not say "yes because the margin is positive," which is where a candidate who stopped at step three would land.

 

What Math Should You Expect in a Utilities Case?

 

The arithmetic is straightforward, but the units are unforgiving. Almost every quantitative mistake I have seen in a utilities case came from confusing power with energy, not from bad multiplication. Master these conversions and you will handle 90% of what comes up.

 

• Power versus energy: a megawatt is a rate, a megawatt hour is a quantity, and 1 MW running flat out for a year produces 8,760 MWh

 

• Scale: 1 gigawatt equals 1,000 megawatts, and 1 megawatt hour equals 1,000 kilowatt hours

 

• Capacity factor: actual output divided by maximum possible output, which is why 1 GW of solar produces far less annual energy than 1 GW of nuclear

 

• Rate base return: rate base multiplied by the allowed rate of return gives the utility's permitted profit

 

• Bill math: monthly kilowatt hours multiplied by the rate per kilowatt hour, useful for translating a rate increase into a customer impact

 

Long-lived assets also mean discounting shows up more often than in other industries. Be ready to run a quick NPV case interview calculation or a payback period on a 30-year investment.

 

Practicing case interview math with large numbers and unit conversions is the highest-return prep you can do for this sector. Drill the conversions until they are automatic, because doing them slowly under pressure reads as weak quantitative skill even when your answer is right.

 

What Mistakes Do Candidates Make in Utilities Cases?

 

Having coached hundreds of candidates one on one, I see the same handful of errors repeat in this sector. Each is easy to avoid once you know it is coming.

 

Tip #1: Stop reaching for the profitability framework

 

The instinct to open with revenue minus cost is strong, and in a regulated utility it is wrong. Rates are set by a commission, so "increase price" is not a lever the client controls. Build your branches around capital, recovery, customers, and risk instead of borrowing a profitability case interview tree wholesale.

 

Tip #2: Ask whether the market is regulated or competitive first

 

This one clarifying question reshapes the entire case. A retail energy client in Texas can compete on price and churn, while a wires company in Georgia cannot. Candidates who skip it end up building a structure that does not apply to the client.

 

Tip #3: Name the regulator as a stakeholder

 

Every recommendation involving capital has to survive a rate case. Saying "we would need commission approval, and here is how we would make that case" separates candidates who understand the industry from those who have only read a framework guide. It takes one sentence and it lands every time.

 

Tip #4: Check your units out loud

 

State the unit with every number you calculate. Megawatts, megawatt hours, and kilowatt hours look similar on scratch paper and differ by factors of a thousand. Interviewers notice unit discipline, and it costs you nothing.

 

Tip #5: Bring affordability into the answer

 

Residential electricity prices have been rising, and regulators are under real political pressure about bills. A recommendation that adds $200 million of capital without addressing what it does to the average customer's monthly bill is incomplete. Quantify the bill impact even roughly and you will stand out.

 

Tip #6: Treat decarbonization as economics, not ideology

 

Solar reached 8% of US generation in 2026 while coal fell to 16%, according to EIA data, and that shift is driven mostly by cost and policy rather than preference. Discuss it in terms of levelized cost, capacity value, and regulatory mandates, which is also how an ESG case interview should be handled.

 

Which Consulting Firms Do the Most Utilities Work?

 

Every major strategy firm has a power and utilities practice, and the sector is one of the largest sources of consulting revenue globally. McKinsey states that its Electric Power and Natural Gas Practice has worked with 450 global power and gas utility clients since 2014, serving eight of the top ten North American electric power leaders. BCG runs a dedicated power and utilities practice covering regulated and unregulated players across transmission, distribution, generation, and retail.

 

Bain approaches the sector through its Energy and Natural Resources practice, with heavy private equity diligence work on generation and infrastructure assets. Deloitte, Accenture, PwC, and EY run large power and utilities units focused on grid modernization, billing systems, and operational transformation, and they hire in volume. Boutique energy specialists and engineering advisory firms round out the market.

 

If you are choosing where to apply, the practice mix matters more than the firm brand, and comparing the top consulting firms by industry is a faster way to target your applications than reading general rankings. A utilities case interview is not testing whether you can recite the value chain. It is testing whether you understand that a regulated monopoly grows by investing capital a regulator approves, so build every structure around that idea and pressure-test the risk on the other side of a 30-year asset.

 

Frequently Asked Questions

 

How hard is a utilities case interview compared to a normal case?

 

The case structure is the same, but the profit logic is different. In a regulated utility, revenue is set by a regulator rather than by the market, so the usual levers of raising price or selling more volume are mostly unavailable. Candidates who try to force a standard profitability framework onto a regulated client tend to stall in the first two minutes. Once you understand rate base regulation, utilities cases are no harder than any other industry case.

 

Do I need an energy background to pass a utilities case interview?

 

No. Interviewers expect you to know the value chain, the difference between regulated and competitive markets, and roughly how a utility earns a return. They do not expect engineering knowledge about turbines, voltage levels, or grid physics. Two or three hours of focused industry reading is usually enough to close the gap.

 

What is rate base and why does it matter in a case interview?

 

Rate base is the value of the capital assets a regulator has approved for cost recovery, such as power plants, substations, poles, wires, and pipes. The regulator allows the utility to earn a set percentage return on that rate base. It matters because it means a regulated utility grows profit primarily by investing more capital, not by selling more electricity.

 

What kinds of utilities cases do McKinsey, BCG, and Bain actually give?

 

The most common are load growth and capacity planning, rate case and regulatory strategy, capital program and cost reduction, and reliability or outage performance. Market entry and asset acquisition cases show up in competitive generation and retail energy. Each of these mirrors real client work at the major power and utilities practices.

 

What math should I expect in a utilities case interview?

 

Expect unit conversions between megawatts and megawatt hours, capacity factor and load factor calculations, rate base multiplied by an allowed return, and simple payback or net present value math. The arithmetic is not advanced, but the units trip candidates up constantly. Practice converting a megawatt of capacity into annual energy before your interview.

 

Is a water utility case different from an electric utility case?

 

The economics are nearly identical because both are regulated monopolies that earn a return on approved capital. The differences are operational. Water cases usually center on pipe replacement, treatment compliance, and water lost between the treatment plant and the customer, while electric cases center on generation mix, grid capacity, and reliability.

 

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