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:
- 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.
- 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.
