The Solar Power Duck Curve Explained

With the increasing demand for electricity as the world shifts away from fossil fuels, cleaner sources of energy like solar and wind are becoming more and more common.

However, as more solar power is introduced into our grids, operators are dealing with a new problem that can be visualized as the “duck curve.”

Origins of the Duck Curve

In a world heavily reliant on electricity, utility companies have gotten better at using data to anticipate demand and trying to operate as efficiently as possible.

Usually, power companies supply the least amount of power overnight while most consumers are sleeping, ramping up during the morning as people wake up and businesses get going. Then, at sunset, energy demand peaks.

Utility companies use models to predict demand and operate as efficiently as possible by supplying more power during times of higher demand. But the introduction of solar power has brought about problems in these demand curve models.

Since solar power relies on the Sun, peak solar production occurs around midday, when electricity demand is often on the lower end. As a result, energy production is higher than it needs to be, and net demand—total demand minus wind and solar production—falls. Then, when evening approaches, net demand increases, while solar power generation falls.

This discrepancy results in a net demand curve that takes the shape of a duck, and the duck curve gets more pronounced each year, as more solar capacity is added and net demand dips lower and lower at midday.

Why the Curve is Ruffling Feathers

The drop in net demand at midday basically creates two problems:

1. Solar energy production wanes as the sun sets, just as demand for energy typically peaks. Utility companies are having to ramp up production to compensate for this gap, often overstressing a grid that is not yet set up for these peaks.
2. Traditional sources of energy like nuclear and coal are only economic when they are running all the time. If you have to turn them off at mid-day because the power is supplied by solar, they become economically unfeasible.

Due to overproduction, solar power is already being wasted in some places where the technology is widely used, like California.

The problem is most intense during summer or spring when part of the solar panels has to be turned off to avoid overloading or even damaging the power grid.

Flattening the Duck

With more countries starting to rely on solar power, there are many potential solutions for the duck curve being explored (and implemented):

• Energy Storage: Overproduction of solar power during the day can be utilized by improving batteries and grid storage capacity.
• Powering Alternatives: Extra solar power can go towards powering energy generation at night, such as pumping water for hydroelectricity or overheating a material to dissipate energy later.
• Other Clean Sources: Unlike solar energy, sources like nuclear, hydroelectric, and geothermal can operate continuously and fill in the demand gap.

While grid managers study how to serve the new supply and demand, the duck curve is one of the greatest challenges facing renewable energy.