Duck Curve Solutions

The duck curve has two problems: too much solar at midday and too little generation at sunset. No single technology solves both. The emerging solution is a portfolio: batteries absorb the belly and shave the ramp, demand shifting moves load into solar hours, and regional transmission spreads solar output across time zones.

Batteries charge during midday oversupply and discharge during the evening ramp. CAISO deployed over 10 GW of battery storage by 2024, and the evening net load peak has visibly flattened. Duration is still the constraint: four hours of discharge cannot carry the whole evening.

Demand shifting moves electricity consumption into solar hours. EV charging schedules shift to midday. Industrial processes that can flex (water heating, desalination, hydrogen electrolysis) absorb midday surplus. CAISO's time-of-use rates charge customers more during evening peak and less during solar hours, creating financial incentive to shift.

Regional transmission exploits time zone diversity. When California has midday surplus, mountain and eastern states are approaching their afternoon peaks. Transmitting surplus power eastward turns California's oversupply into Arizona's or Nevada's daytime supply.

A typical CAISO spring day, 2024. Batteries charge several gigawatts during midday (absorbing surplus), time-of-use rates shift some demand into solar hours, and interregional exports move surplus power eastward.

Is the duck curve solvable?

It is being solved, incrementally. CAISO's evening ramp is less steep than five years ago despite higher solar penetration. But the belly keeps deepening as more solar is added, requiring ever more storage and demand flexibility. The duck curve is not a problem to be solved once but a condition to be continuously managed as solar grows.

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