Lesson 7 of 7

Market Design & the Energy Transition

8 min read

Every market mechanism covered in this track — merit order, LMP, ancillary services, capacity accreditation, PPAs — was largely designed for a grid dominated by dispatchable, fuel-burning generation. This final lesson looks at where that design is genuinely straining under a very different generation mix, tying this whole track back to the Renewable Energy and Grid Stability tracks.

The near-zero marginal cost problem

Merit order dispatch, from earlier in this track, calls on the cheapest available generator first. Wind and solar have essentially zero marginal cost — once built, generating one more megawatt-hour costs almost nothing — so they're dispatched ahead of almost everything else whenever available. That's efficient in the moment, but it also means the market-clearing price during high-renewable hours can collapse toward zero (or below, as covered in the LMP lesson), which is exactly the missing money problem in its most acute modern form: even the plants the system will still badly need during low-renewable hours may struggle to earn enough during the hours when renewables dominate.

Where the duck curve shows up in prices

The duck curve, introduced in the Renewable Energy track, has a direct market signature: prices tend to be very low (or negative) during the midday solar trough, then spike sharply during the evening ramp as solar disappears and other generation has to ramp up fast. This volatile daily price pattern is itself a market signal encouraging exactly the resources that help — batteries that charge cheap at midday and discharge expensive in the evening, and demand response that can shift load away from the evening peak.

Markets adapting to solve the problem they created

This is one of the more elegant dynamics in the whole track: the same price volatility that renewables introduce is also the economic signal that makes storage and flexible demand profitable, which in turn helps smooth out that very volatility. It doesn't happen automatically or perfectly, but it's a real example of price signals doing useful coordination work without anyone centrally planning the solution.

How market design is actually responding

Faster market intervals: Moving real-time markets to 5-minute (or sub-5-minute) intervals lets prices reflect fast renewable variability more accurately than older 30- or 60-minute intervals could.
Sloped, faster ancillary service products: New reserve and regulation products designed specifically for battery-speed response, going beyond the traditional 10-minute and 30-minute categories covered earlier in this track.
Storage-specific market rules: Rules addressing storage's unique ability to both buy and sell power, which didn't fit cleanly into market structures designed around one-directional generators.
Evolving capacity accreditation: As covered in the capacity markets lesson, moving beyond simple nameplate ratings toward hour-specific expected contribution during system stress.

Closing the loop on this whole track

Every earlier lesson in this track described a mechanism built for a particular problem: merit order for efficiency, LMP for location, ancillary services for stability, capacity markets for adequacy, contracts for risk. None of those problems disappeared with more renewables — they just got harder to solve well, which is exactly why electricity market design remains an active, unfinished area of engineering and economics, not a solved textbook problem with one correct answer.

Key takeaways

Wind and solar's near-zero marginal cost pushes market prices toward zero during high-output hours, sharpening the missing money problem.
The duck curve has a direct price signature — low midday prices, sharp evening spikes — that itself incentivizes storage and demand flexibility.
Market design is adapting with faster intervals, new fast-response ancillary products, storage-specific rules and refined capacity accreditation.
Electricity market design remains an active, evolving field, not a fixed set of rules — every mechanism in this track is still being adapted for a changing generation mix.