ECO 101 · Unit 3 · Lesson 1 of 5
Preferences and Consumer Choice
Consumer and Firm Decisions
Lesson
Customers choose bundles, not single numbers
ClearPeak's time-of-use (TOU) pilot offered households a choice: flat bundled rate at $0.118/kWh or a peak/off-peak bundle with cheaper overnight energy and pricier summer afternoons. Uptake split sharply by income, appliance stock, and work-from-home status. Dr. Elena Vasquez told regulators the pilot was not "price sensitivity" alone; it was consumer choice under a budget constraint with heterogeneous preferences.
Preferences rank bundles of goods. Utility (U, satisfaction from consumption) summarizes those rankings. A rational consumer picks the affordable bundle that reaches the highest utility. ClearPeak cannot assume one household behaves like 1.2 million identical customers.
ClearPeak Energy is a regulated regional electric utility serving 1.2 million residential and commercial customers across twelve counties and the anchor organization for ECO 101. The utility faces retiring 2,400 MW of coal while adding 1,800 MW of utility-scale solar and battery storage by 2030, peak summer demand near 8,500 MW, and an average residential bundled rate of $0.118/kWh (kilowatt-hour, enough electricity to run ten 100-watt bulbs for one hour). Chief Economist Dr. Elena Vasquez, Regulatory Affairs VP Tom Bradley, and Grid Planning Director Amara Okafor use microeconomic tools for rate design, capacity planning, competitive response, and State Public Utilities Commission (PUC) testimony. Marginal generation costs differ sharply: legacy coal near $0.042/kWh, new solar near $0.031/kWh, and gas peakers near $0.067/kWh when scarcity bites.
Every lesson applies supply, demand, elasticity, marginal analysis, market structure, or incentive design to decisions ClearPeak leaders actually face: when to retire plants, how to price time-of-use tiers, how to bid in capacity auctions, and how to respond when rooftop solar erodes sales.
Preferences, utility, and indifference curves
An indifference curve connects bundles a consumer values equally. Higher curves mean higher utility. Curves slope downward (tradeoffs) and bow inward (diminishing marginal rate of substitution). For electricity, the "goods" might be peak kWh and off-peak kWh, or energy versus other spending.
Graph (described in prose): Budget line and indifference curve tangency. Imagine a standard microeconomics diagram with off-peak kilowatt-hours per month on the horizontal axis and peak kilowatt-hours per month on the vertical axis. An indifference curve bows toward the origin: the consumer is willing to give up fewer peak kWh as off-peak consumption rises. A straight budget line shows affordable combinations at given TOU prices; its slope equals the negative price ratio. Optimal choice is where the budget line is tangent to the highest reachable indifference curve: marginal rate of substitution equals price ratio. Interior tangency means both goods consumed; corner solutions occur when one price is so high the consumer avoids that good entirely.
Budget constraints and rate bundles
Budget: p_peak × Q_peak + p_off × Q_off ≤ income allocated to electricity. A 10% peak price rise rotates the budget line inward on the peak axis, pushing consumers toward off-peak substitution if they can shift load.
| Bundle | Peak $/kWh | Off-peak $/kWh | Typical chooser |
|---|---|---|---|
| Flat | 0.118 | 0.118 | Renters, limited flexibility |
| TOU standard | 0.162 | 0.078 | EV owners, programmable HVAC |
| TOU + critical peak | 0.210 | 0.078 | High-income, battery-ready |
Marginal utility and diminishing satisfaction
Marginal utility (MU, extra satisfaction from one more unit) typically falls as consumption rises. The 50th kWh of afternoon cooling adds less utility than the 5th. Diminishing MU explains downward-sloping demand without assuming irrationality.
Revealed preference at ClearPeak
Pilot enrollment, thermostat schedules, and bill payment under TOU reveal preferences better than survey intent. Elena pairs stated surveys with observed load shapes from AMI (advanced metering infrastructure) meters.
Equity and heterogeneous preferences
Low-income households with old AC units may prefer flat rates even if TOU is cheaper on average, because peak exposure is harder to shift. Preference modeling informs LMI (low- and moderate-income) bill protection tiers.
Worked example: TOU bundle choice for two households
Monthly electricity budget $120. Prices: peak $0.18/kWh, off-peak $0.07/kWh.
Part A: Household A (flexible)
Chooses 300 peak + 900 off-peak kWh. Spend = 300×0.18 + 900×0.07 = $54 + $63 = $117. Utility high from cheap overnight EV charging.
Part B: Household B (inflexible)
Needs 550 peak + 400 off-peak. Spend = 550×0.18 + 400×0.07 = $99 + $28 = $127, exceeds budget. B cuts peak to 480: $86.40 + $28 = $114.40. Check: 480×0.18 = $86.40 ✓
Part C: Regulatory read
Same tariff, different chosen bundles. Average bill comparisons hide preference heterogeneity.
Part D: Managerial read
Report distribution of peak share, not only mean bill change, in PUC filings.
Worked example: Corner solution
SunGrid commercial tariff priced peak power so high that three manufacturers shifted entirely to night shifts (off-peak only). Indifference curves touched the off-peak axis: corner optimum, not interior tangency.
Common mistakes beginners make
| Mistake | Reality |
|---|---|
| One representative consumer | Model segments with different load flexibility |
| Utility from income alone | Utility ranks bundles; income is budget |
| Ignoring corner solutions | Some households cannot shift peak AC |
| Stated intent without AMI data | Use revealed load shapes |
| TOU average bill as fairness proof | Show bill distribution by income decile |
Practice problem
Budget $90. Peak $0.15/kWh, off-peak $0.06/kWh. Consumer chooses 400 off-peak and 200 peak. Total spend? Under budget? If they want 50 more peak kWh, how many off-peak kWh must they give up at the margin (price ratio)?
Solution
Spend = 200×0.15 + 400×0.06 = $30 + $24 = $54. Under $90 budget by $36. Price ratio: peak/off-peak = 0.15/0.06 = 2.5, so 50 peak kWh costs as much as 125 off-peak kWh at the margin. Check: 50×0.15 = $7.50; 125×0.06 = $7.50 ✓
Key takeaways
- Consumers maximize utility subject to budget constraints.
- Indifference curves and budget lines predict TOU bundle choices.
- ClearPeak pilots must analyze heterogeneous preferences, not mean bills.
- Revealed preference from AMI beats intent surveys alone.
- Equity analysis requires segment-level choice data.
After this lesson
- Sketch a budget line for ClearPeak flat vs TOU prices.
- Name one corner solution for residential peak electricity.
- Continue to Lesson 2: Marginal Analysis.
Applying Preferences and Consumer Choice at ClearPeak scale
When ClearPeak Energy evaluates preferences and consumer choice, Dr. Elena Vasquez starts from operational facts: 1,200,000 customers, peak demand near 8,500 MW, residential bundled rate $0.118/kWh, and a portfolio transition that retires 2,400 MW of coal while adding 1,800 MW of solar. consumer choice, marginal analysis, and production costs is not textbook decoration; it is how Tom Bradley prepares State Public Utilities Commission (PUC) filings and how Amara Okafor ranks transmission and storage options under binding capital budgets.
Graph (described in prose): Preferences and Consumer Choice at ClearPeak. Imagine a standard microeconomics diagram with quantity (megawatt-hours or customer count, depending on the decision) on the horizontal axis and price ($/kWh) or marginal cost ($/kWh) on the vertical axis. The demand curve slopes downward: at higher retail rates, customers conserve, shift load to off-peak hours, or install rooftop solar. The supply curve in the short run reflects rising marginal cost as ClearPeak dispatches coal, combined-cycle gas, and expensive peakers. Equilibrium is where quantity demanded equals quantity supplied at a price regulators allow; in regulated markets, equilibrium is a negotiated outcome, not only a frictionless auction. When ${title.toLowerCase()} changes, curves shift: new solar lowers long-run supply cost; heat waves shift demand right; competitor solar leases shift demand left for utility energy. Shaded consumer surplus and producer surplus (or deadweight loss when prices depart from marginal cost) translate directly into affordability testimony and earnings impacts.
Work a magnitude check. Suppose a policy tied to preferences and consumer choice moves residential sales by 1% at current scale. One percent of 1,200,000 customers is 12,000 accounts. At roughly 900 kWh per month average use and $0.118/kWh, a 1% quantity change moves monthly revenue by about $1.3 million before fuel cost adjustments. Executives who skip arithmetic like this debate symbols without stakes.
Extended ClearPeak scenario: regulatory and competitive read
Imagine ClearPeak's quarterly review on preferences and consumer choice. Finance asks whether a rate increase recovers rising gas peaker costs. Operations asks whether demand response can defer a $400 million substation upgrade. Commercial customers ask for advanced metering discounts. Rooftop solar installers tell regulators ClearPeak exercises market power. A weak consumer choice, marginal analysis, and production costs answer addresses only one audience. A strong answer links curves, elasticities, and marginal costs to each stakeholder's metric.
Dr. Vasquez uses a three-panel narrative. Panel one: short-run dispatch when peak load hits 8,500 MW and peakers set marginal cost near $0.067/kWh. Panel two: long-run portfolio when solar at $0.031/kWh displaces coal at $0.042/kWh plus carbon compliance. Panel three: competitive fringe where distributed solar at $0.09/kWh effective price steals high-margin afternoon sales. Preferences and Consumer Choice supplies vocabulary to keep the panels consistent.
Numerical discipline example: if price elasticity of residential demand is -0.35 (a 1% price rise cuts quantity about 0.35%), a 4% rate increase reduces energy sales roughly 1.4% in the short run. Combined with weather normalization, Elena reports a bounded revenue forecast instead of pretending demand is fixed. Regulators punish utilities that ignore elasticity in revenue requirement testimony.
Technical mechanics and reconciliation checks
For preferences and consumer choice, ClearPeak analysts show work the way accountants show trial balances. A supply table lists plant, capacity MW, heat rate, variable O&M, fuel cost, and marginal cost per MWh (megawatt-hour). A demand table lists customer class, price, quantity, and expenditure. Equilibrium checks that quantity demanded equals scheduled dispatch within reserve margin rules. Elasticity checks recompute percent changes with the same denominator conventions used in the tariff filing.
Use explicit formula lines before plugging numbers. Elasticity = percent change in quantity demanded divided by percent change in price. Marginal cost = change in total cost divided by change in output. Marginal revenue = change in total revenue divided by change in quantity sold. Consumer surplus approximates the area below demand and above price for the units consumed. When lessons use linear demand shortcuts, state the assumption: "linear between two observed tariff points."
Spreadsheet grain matters. Utility models often run hourly for dispatch, monthly for billing, and annual for regulatory revenue requirements. Preferences and Consumer Choice fails silently when rows mix grains. Elena requires a grain column in every workbook: hour, month, customer-month, or plant-year.
Common executive questions (and disciplined answers)
Executives ask short questions that need long disciplined answers. "Can we pass fuel costs through?" maps to allowed riders, elasticity, and affordability indices, not anger on social media. "Will solar kill the utility?" maps to cross-price elasticity with distributed energy and fixed cost recovery. "Why not cut rates to grow?" maps to marginal revenue sign when |elasticity| < 1. "What is fair return?" maps to allowed revenue requirement and cost of capital, not last year's earnings plus 10%.
ClearPeak's credible answer format for preferences and consumer choice is three bullets: recommendation, key elasticities or marginal costs behind it, and what evidence would reverse the view within two quarters. A fourth bullet names deadweight loss or equity tradeoffs when policy moves price away from marginal cost.
Practice the translation loop until habit: business question → curves and elasticities → quantity and revenue arithmetic → stakeholder table → filing language. Broken loops produce pretty charts that fail cross-examination.
Practice extension: graph and arithmetic self-check
Before re-reading solutions, sketch four items on paper. Item one: draw (in words) demand and supply for ClearPeak summer peak hours with labels. Item two: write one shift that increases price and one that decreases quantity without a price change. Item three: compute percent ΔQ and percent ΔP for a scenario in the lesson and verify elasticity sign. Item four: state who gains and who loses in surplus terms.
Compare your sketch to the worked example. Gaps tell you what to re-read. If you work outside utilities, substitute your product but keep the same structure: define market, state margins, show equilibrium, stress-test with elasticity.
Connection to ACC 101, MKT 202, and capstone design
ACC 101 taught you to reconcile statements; ECO 101 teaches you to reconcile marginal stories with average costs regulators allow. MKT 202 taught evidence ladders; here the ladder is descriptive load research → elasticity estimation → pricing experiment or pilot tariff → regulatory approval. Unit six capstone on designing incentives expects you to combine consumer choice, marginal analysis, and production costs with game theory and externality tools from earlier units.
Integrated narrative example: ClearPeak proposes a peak-pricing pilot (MKT-style segmentation), estimates elasticity −0.35 (ECO 101 Unit 2), models revenue with marginal cost dispatch (Unit 3), and defends fairness to the PUC (Unit 6). Courses compound when vocabulary and numbers stay consistent.
Deep dive: ClearPeak data definitions reused every month
Residential bundled rate includes energy, distribution, and mandated riders; pilots may unbundle for time-of-use. Peak demand is the highest hourly load in a month; coincident peak may determine transmission charges. Marginal cost of service for pricing studies uses forward-looking dispatch, not historical average embedded cost. Lost revenue from energy efficiency or solar is offset by decoupling mechanisms in some filings. Elasticity estimates separate weather, price, income, and appliance stock effects.
Definition drift fakes wins. If operations reports peak MW using one weather adjustment and finance uses another, preferences and consumer choice recommendations flip. Elena publishes a one-page data dictionary before each major filing.
Monthly reconciliation: billed energy ≈ generation net losses ± inventory; revenue ≈ Σ quantity × tariff by class; marginal cost tables sum to dispatch cost within rounding. Elasticity replays on holdout months. When reconciliations fail, fix data before arguing policy.
Managerial judgment prompts for Preferences and Consumer Choice
- If elasticity is inelastic short run but elastic long run, how should ClearPeak sequence a multi-year rate path?
- If marginal solar cost is below coal but fixed grid costs rise, is average cost or marginal cost the right public narrative?
- Which stakeholder loses most if ClearPeak underestimates cross-price elasticity with rooftop solar?
- What observable would convince you the demand curve shifted versus movement along the curve?
- When does surplus language help regulators and when does it sound like economist jargon?
Write ninety-word memo answers using ClearPeak numbers. This converts lesson prose into testimony reflexes.
Additional study path: compare this lesson's practice problem to the worked example. Identify one assumption that changed elasticity or marginal cost and explain how the decision flips. Capstone integration is intentional; reuse ClearPeak names and units across units.
Numerical walk-through: peak hour dispatch
Consider a summer peak hour with 8,500 MW demand. ClearPeak dispatches 3,200 MW coal at $0.042/kWh variable, 3,800 MW combined-cycle gas at $0.055/kWh, 800 MW solar at near-zero variable cost, and 700 MW peakers at $0.067/kWh. The marginal unit sets price in competitive benchmarks; in regulation, the filing may use average revenue requirement. Weighted average variable cost ≈ (3200×0.042 + 3800×0.055 + 800×0.005 + 700×0.067) / 8500 ≈ $0.046/kWh before T&D (transmission and distribution).
If preferences and consumer choice motivates shifting 200 MW from peak to off-peak via time-of-use pricing, peaker runs drop, variable cost falls roughly 200×$0.067 = $13,400 per hour, plus avoided capacity charges if sustained. Demand response programs trade customer incentives against this savings. Elena documents both gross savings and participation costs; net benefit drives the filing.
Check: 3200+3800+800+700 = 8500 MW ✓. Any lesson using partial portfolios should show similar capacity checks.
Surplus, equity, and policy tradeoffs
Microeconomics is not only efficiency. Preferences and Consumer Choice at ClearPeak intersects affordability programs for low-income households, equity when time-of-use shifts burden evening home use, and environmental justice when retired coal plants sit in vulnerable communities. Consumer surplus gains for average bills may hide losses for heat-vulnerable customers.
When lessons recommend raising price toward marginal cost, pair the recommendation with a transfer or assistance mechanism or explain why the PUC weights equity constraints. Dr. Vasquez tables deadweight loss of under-pricing peak energy alongside hardship metrics. Regulators accept tradeoffs stated clearly; they reject efficiency claims that ignore distributional facts.
For consumer choice, marginal analysis, and production costs, practice writing one paragraph that a non-economist commissioner could read aloud. Avoid surplus jargon without translation: "customers who value afternoon cooling less than the cost of peaker plants would consume less under peak pricing, freeing capacity for hospitals and industrial employers."
Historical filing pattern (synthetic but consistent)
ClearPeak's 2024 time-of-use pilot covered 42,000 households. Control group average peak kWh fell 2.1% from weather normalization; pilot group fell 6.8%. Difference-in-differences estimate 4.7% peak reduction. With pilot peak price +18% versus control flat rate, arc elasticity ≈ 4.7/18 ≈ 0.26 in absolute value on the pilot margin (illustrative, not a policy filing). Revenue net of lost sales rose 1.2% because peak price uplift exceeded quantity loss on inelastic inframarginal hours.
Tom Bradley's lesson for preferences and consumer choice: pilot evidence beats theory slides, but pilots need control groups and pre-registered metrics. Amara links observed peak reduction to deferred substation timing: 4.7% on 420 MW local peak ≈ 20 MW relief, extending asset life two years under stated loading rules.
Cross-price and income effects reminder
Preferences and Consumer Choice rarely operates in isolation. Income elasticity matters when recession hits commercial load. Cross-price elasticity with rooftop solar matters when federal tax credits change. Cross-price elasticity with natural gas matters for dual-fuel customers. Elena keeps a small table of estimated elasticities by class: residential -0.35, commercial -0.55, industrial −0.22 short run.
When interpreting ClearPeak results, ask which elasticity dimension the decision uses. Price-only stories mislead if income or substitute prices moved simultaneously. Multiple-regression control variables belong in advanced courses; the managerial habit here is to name confounds even if you cannot quantify them yet.
Closing integration: from lesson to testimony bullet
Translate preferences and consumer choice into a single testimony bullet ClearPeak could use: claim, mechanism, magnitude, caveat. Example structure: "We recommend expanding time-of-use because peak demand elasticity is modest short run but pilot evidence shows 4–7% peak kWh reduction at +18% peak price, deferring $40M substation spend if sustained two years, with low-income bill protection via tiered credits." Compare your bullet to the lesson takeaways. If magnitude or caveat is missing, deepen the quantitative thread before moving on.
Step-by-step elasticity replay (when relevant to Preferences and Consumer Choice)
Suppose ClearPeak raises the residential energy charge from $0.095/kWh to $0.099/kWh, a 4.2% increase. Prior monthly sales averaged 720 GWh (gigawatt-hours). Estimated short-run own-price elasticity is -0.35. Expected quantity change ≈ -0.35 × 4.2% ≈ −1.47%. New sales ≈ 720 × (1 − 0.0147) ≈ 709.4 GWh.
Revenue before ≈ 720,000,000 kWh × $0.095 ≈ $68.4M per month (energy portion only). Revenue after ≈ 709,400,000 × $0.099 ≈ $70.2M. Despite lower volume, revenue rises because demand is inelastic (|ε| < 1). Tom Bradley uses this arithmetic in filings; Elena notes long-run elasticity may exceed −0.6, reversing the revenue gain over three years. Preferences and Consumer Choice lessons should always pair short-run and long-run elasticity stories when pricing is involved.
Check: percent change formula uses consistent base (midpoint or initial); document which you use ✓
Marginal versus average cost at ClearPeak (cost ladder)
| Plant type | Capacity MW | Average cost $/kWh (all-in) | Marginal cost $/kWh (variable dispatch) |
|---|---|---|---|
| Coal (legacy) | 3,200 | 0.068 | 0.042 |
| Combined-cycle gas | 3,800 | 0.059 | 0.055 |
| Utility solar | 800 | 0.045 | 0.031 |
| Gas peaker | 700 | 0.112 | 0.067 |
Average cost spreads fixed capital and O&M across all units; regulators use it in revenue requirements. Marginal cost tells Elena which plant runs next and what the last megawatt costs on a hot afternoon. Preferences and Consumer Choice decisions fail when teams argue average while the grid dispatches marginal. For peak pricing pilots, marginal peaker cost near $0.067/kWh is the opportunity cost of an extra peak kWh.
Weighted check for variable dispatch stack (8500 MW example): coal+gas+solar+peaker shares sum to 100% ✓
Capstone linkage note (Preferences and Consumer Choice in the full ECO 101 arc)
Unit one gave you curves; unit two gave elasticities; unit three gave costs and scale; unit four gave market power; unit five gave games and information; unit six gives policy design. Preferences and Consumer Choice sits in that arc at ClearPeak: every formula should connect to a filing paragraph Tom Bradley could defend. When you draft recommendations, cite at least two prior-unit tools by name (for example, elasticity from Unit 2 plus externality pricing from Unit 6).
Dr. Vasquez's integrative standard: one page, five bullets, each bullet ties a concept to a number and a stakeholder. No bullet without magnitude. No magnitude without assumption. This is the difference between MBA fluency and undergraduate definition recall.
Lesson exercise
30 minTime-of-use tier design
Deliverable
Two-household preference table and tier proposal.
Rubric
- • Marginal utility per dollar discussed
- • Tiers differ by hour valuation
- • Simplicity tradeoff acknowledged
- • Equity risk named