[1] Its name is derived from its resulting shape that resembles a duck.
Embedded Files
Duck curve
Duck curve
The Duck curve is a graph depicting the timing imbalance between peak electricity demand and solar energy production throughout a day.
[1] Blue curve: Total electrical power demand (load)
Orange curve: (the duck curve) supply of electrical power from dispatchable sources,
Gray curve: supply of solar power
This is California's data on October 22, 2016 (a Saturday), a day when wind power output was low and steady throughout the day.
From 07:00 to 22:00, the orange curve resembles a duck.
From 17:00 to 18:00 as the sun sets, about 5 GW of generating capacity from dispatchable sources must come on line in 1 hour.
Blue curve = Orange curve + Gray curve + wind power
Components
Components
The morning (the "Tail"): As we wake up, turn on lights, and devices, overall electricity demand rises. Solar production hasn't fully kicked in yet, so traditional power plants handle this minor peak.
Midday (the "Belly"): This is when the duck shape appears. During the day, the sun shines brightest, and solar panels flood the grid with clean energy. Since the grid uses this solar power first, demand for traditional power plants (like natural gas or hydro) plummets, causing a drop in the graph—the duck's belly.
Late afternoon/Evening (the "Neck"): As the sun goes down, solar production rapidly drops to zero. At the exact same time, people come home from work, turn on appliances, air conditioning, and TVs, causing the day's highest peak in electricity demand.
The issues But the fast shift from midday low-demand to evening high-demand causes 2 main issues in grid operators:
The extreme ramp rate: Operators must quickly "ramp up" traditional power plants to compensate for the solar energy sudden loss. Generating thousands of MW in just 2-3 hours puts high strain on infrastructures. Traditional fossil-fuel plants must quickly burn extra fuel to reach such sudden spike, which is inefficient and costly.
Overgeneration risk: If too much solar power enters the grid in the day, it can exceed what a region really needs. If the grid can't handle/store the excess electricity, operators must shut off solar fields (called curtailment) to avoid overloading power lines.
The solutions As solar energy grows, power systems are adapting using several tools to smooth out the duck shape:
Energy Storage (Batteries): Big-scale battery facilities charge up during the day using the excess midday solar power (flattening the belly) and release it back into the grid during the evening rush (lowering the neck).
Time-of-Use Pricing: Utilities charge consumers higher rates during peak evening hours. This incentivizes people to run heavy appliances (like dishwashers or washing machines) during the afternoon when solar energy is abundant and cheap.
Sharing Across Regions: Grids can sell their excess daytime solar power to neighboring states or provinces that might still need it, preventing the need to waste the energy.
Page updated
Google Sites
Report abuse