Excess Solar Power Created The Duck Curve
Spring has a unique effect on our electricity grid. Longer days of sunshine generates more solar power. But unlike summer, the cool air of springtime doesn’t incite people to blast their incredibly energy-intensive air conditioning.
The result of these mild factors working in unison: “The Duck Curve”.
But what is the duck curve? And can we do anything about its effect?
The Belly of the Beast
The chart below shows electricity demand in California on Monday, April 1st, 2019.
You’ll see the lowest energy demand occurs during the night and then ramps up as people turn on the lights and coffee pots to start their days.
On most spring days, demand remains fairly constant while offices maintain steady energy usage.
Then, demand ascends as people return home and turn on their TVs, microwaves, and washing machines. Finally, energy demand tapers off as people go to sleep.
Now let’s look at the picture from another perspective.
Massive megawatts (MW) of solar power coming online in the past few years now supplies energy for a portion of the daily demand. But that solar power, provided only when the sun shines, gives us an irregular energy supply.
Take a look at the same April 1st chart but with an additional layer demonstrating the net demand after accounting for the solar supply:
Can you see the duck in the chart with its low springtime belly? The picture below helps to visualize it. And each year as we add more solar, the belly gets deeper and deeper.
Effects of the Duck Curve
All the new solar power has led to overgeneration, particularly during springtime. Therefore, lots of solar power must be turned off, or curtailed, to accurately balance the grid supply and demand.
Ryan Mann, Analyst extraordinaire of Energy Storage & Distributed Energy Resources at Enel X, believes that 20-gigawatt hours (GWh), or 11% of total renewable production, were curtailed on March 31st, thereby declaring the date the grid’s official “Duck Day”.
You can see how electricity in CA is produced and used each day and how it forms the duck curve in real-time.
If you want a more granular understanding of why this happens, watch this video:
Curtailment — isn’t it ridiculous? We have these beautiful clean electrons ready to power our lives but we throw them away because they aren’t available when we want them.
We’ve previously discussed storing this “lunch-time energy” so we can use it as “dinner-time energy”; those giant storage projects require utility-scale resources. And Mann states that “Deploying enough lithium-ion batteries to store all of this otherwise-wasted energy would cost approximately $14 billion”.
Putting the Duck on a Diet
The goal is to flatten the peaks (head & tail) and the belly of the duck curve.
Besides throwing heaps of money at energy storage, we can shift electricity demand to mid-day to soak up the excess solar. Using our energy resources more efficiently would thereby lower the cost to all of us energy users.
Here are some ways to do so:
Electric Vehicle (EV) Charging: EV sales are escalating at an exponential pace and charging them during the day can dramatically decrease the curtailment of solar. It also leaves the door open for vehicle-to-grid capabilities.
Load Shifting: Utility companies can incentivize people to use energy during the day by charging lower prices during the belly of the duck curve and higher prices during the evening peak. These are called Time Of Use (TOU) rates and some utilities have begun implementing them.
Agricultural Load Shifting: Pumping water for irrigation and other agricultural necessities requires sizable energy. Pumping water during the day can lower utility costs and increase grid reliability (Utility Dive).
ACT ON CLIMATE
Plastic in the ocean is a problem of which we’re all aware. But plastic microfibers that end up in the seafood we consume… that’s a whole other issue entirely. Check out and share this brilliant video by Mac Schneider that sheds light on the microplastics making their way up our food chain:
