The Duck Curve - How is it a Hindrance for the Solar Market?
Posted on January 11 2019
The Duck Curve, yes you read it right, Duck Curve is a thing! And as funny as it is essential for our solar power renewable energy resource enthusiasts. However, in general everyone should know about it. Apart from its importance, it is also fun and cool to say, "hey! I know about the DUCK CURVE".
The duck curve, in the briefest of descriptions, is the induced fluctuation by renewable energy resources into the electricity demand curve.
A duck .via medium
How do current Electricity Grids work? How much power do they generate?
To understand the duck curve, you first need to understand the grid’s current working method. When you flip the switch of a light bulb, you expect it to lighten up. That is because your power supply company is working for you and is continually generating enough power to supply you and all your neighbours with sufficient energy. For years, energy consumption has been in a stable and continuous pattern throughout the day. This helps grid managers to manage and maintain power generation as per the needs, no more no less.
A typical day energy demand and its sources. via diaolgueearth
For many years a steady and predicted model helped grid managers to keep a perfect balance between the supply and demand of electrical energy. Grid managers love this! A typical energy demand graph looks like the following - a two-humped camel. At night, people are not using much energy, all TVs and extra gadgets are powered-off. Then around 7-9 am there is a small surge in power consumption when daily life gets kicking, and then during midday and until 5 pm, there is somewhat a constant power consumption. During the sunset and until consumers go to bed, that is the peak-time of energy consumption, people are watching TV, cooking and doing tons of other stuff with electricity.
California 2012 avg daily electricity demand resembled a two-humped camel shape. via insideenergy
How has solar energy changed the Energy Demand Curve? California Case Study.
With the rapid technological growth in the solar power market, solar panels are getting cheaper and at the same time more efficient as well. This has brought about many companies and customers to install solar panels on their property. Especially after 2010, in the US, solar panels sales saw a big hike, specifically in the state of California. So researchers decided to study how it would affect the grid and see what can be found interesting out of this.
Solar panels on a private property. via pv-magazine-usa
The surged sale in solar panels presented the researchers with the infamous duck curve! Energy demand graph fluctuated due to the massive input from solar energy. From after-morning surge until sunset peak, instead of having a smooth and flat power consumption line, the net energy demand curved downward, like a duck’s belly.
The duck curve prediction for 2020 for California. via ilsr
This phenomenon was observed because solar panels would generate most of the power consumers needed during the day-time, and that meant people were relying less and less on the grid during the mentioned time period. Moreover, with the many policies for promoting solar energy in the United States and globally, we will see a further increase in solar panels. More solar panels would in result mean a steeper and deeper duck's belly.
Duck Curve - the hindrance it brings along for PV solar panels.
Why is the Duck Curve an issue at all? The answer lies within the same problem that grid managers try to avoid by having consistent and predictable energy requirement patterns. This is so that they do not produce more energy than is being required. Another major issue that the Duck Curve introduces is the rapid power ramping, especially at dusk.
Steepness in the duck curve is the primary problem. via insideenergy
You see that energy is not like our water resource, that you can simply store it in a dam or lake; at least, not until now. We don't store energy in the form of electricity. Be it is from the solar panels or the grid, whenever there is more energy generated than required, it is just wasted! Excess power in the system means damaging the grid and losing capital as well. And with a regular change in the duck curve each year, it is tough for grid managers to predict and accurately generate the right amount of energy.
We need to store energy to tackle the duck curve problem. via nuclear-news
With more and more solar panels, we might be approaching the point where duck curve’s belly drops down to almost or below zero! Over generation and absolutely no dependency on the grid during the day-time (at least peak sun hours). This will not only force grid stations to completely shut-down during the day-time and restart during dusk hours later (which brings another issue with itself), but also introduces steep energy demands during the dawn and dusk when people are on the move. For one, the current grid system is not made to withstand and support such great power rampages, and two - the other major problem with this situation is the Energy Economics.
A coal power plant. via abc
As you know most of the power in the grid comes from coal and nuclear power plants - a stable and steady source of power supply. In addition, the sudden surges in power demand are matched with relatively expensive power sources, e.g. electricity generated from oil, natural gas and biofuel - which do not need to be run 24/7 and are easily operated on small notices. However, coal and nuclear energy plants are only beneficial and cheap if they are run round-the-clock. Bringing them to a full stop during midday, and then restarting them around sunset is highly inefficient to the system and infeasible to the economics of power generation. So you either run these plants or don't. If you do run them you risk over-production, if you don't run them you risk underproduction, and if you run them partially it's impractically expensive. That is the Ducks Curve Problem.
Solving the Duck Curve
Well, there are a few more problems with the Duck Curve, but the above two are the most important ones to keep an eye on and know about. So, for now, the most significant challenge renewable energy faces, and especially solar power, is the duck curve. How to achieve a balance when you cannot predict the sun's radiation, it can get cloudy and rainy and then all of a sudden the demand for energy will rocket-fly to the sky. However, don't get me wrong here, there are many proposed solutions for the duck curve, but all that will be discussed in the next blog.
Tesla's power storage batteries. via treehugger
In general, if governments want everything to be run on solar, then they have to solve this duck curve problem largely by storing solar energy, and later using it at night-time. To achieve this goal, the current battery storage system is not efficient and affordable enough. Power storage is one market that has to improve drastically for this solution to be even near a possibility. So that extra energy generated during midday is stored, and then used later on at night especially during the dusk energy demand ramp and the duck curve is flattened out as much as possible.
The new Duck Curve in market. via insideenergy
Still confused with Duck Curve? Got some more questions? No worries, leave a comment down below with your query, and we will help you with it. Stay tuned for more exciting blogs! SUAOKI - MORE POWER, LESS FOOTPRINT!