The Duck Curve: What Is It and Is It a Drawback? – CNET

What appears to be like like a duck, would not quack and is inflicting a lot of complications for vitality utilities all over the world, particularly in California? It’s the duck curve, and it might have a giant impression on the way in which your utility treats your rooftop photo voltaic manufacturing.

Why? Energy grid operators are all the time performing a balancing act between the era of electrical energy and the demand for it. Too a lot vitality means assets are going to waste. Too little and you could have blackouts or brownouts. Still, there may be some predictability for demand. When most individuals are asleep at night time, demand is at its lowest. As our alarm clocks rock us out of our beds and we begin flicking on lights and making breakfast, demand will increase. Demand then stays flat or dips through the day as individuals work. As individuals return house, demand will increase as individuals cook dinner dinner and probably stream some TV. Then the cycle repeats.

Things have been pretty easy for utilities when there have been solely a few sources of vitality manufacturing, particularly fossil fuels like pure gasoline. Adding solar energy to the combo has sophisticated issues.

“Unlike conventional power plants (for example, nuclear, coal-fired and natural gas-fired plants), solar and wind resources can’t be fully dispatched at will to help meet demand, and utilities may have to curtail them to protect grid operations,” in line with the US Energy Information Administration. “Solar power is only generated during daylight hours, peaking at midday when the sun is strongest and dropping off at sunset. As more solar capacity comes online, conventional power plants are used less often during the middle of the day, and the duck curve deepens.”

So what the quack is the duck curve?

What is the duck curve?

The duck curve is what you get if you plot day by day internet vitality load in California on a graph. It’s known as a duck curve as a result of it finally ends up resembling a duck. 

“As more and more solar comes online, it essentially provides overgeneration,” mentioned Tom McCalmont, CEO of Paired Power. “Solar peaks around noon, when load is not very high, but then ramps up dramatically in the late part of the day when people go home, turn on their ovens and lights, plug in their cars, whatever. The shape of this thing is that you get the belly of the duck.”

The early a part of the day, when demand is up, is the duck’s tail. The center of the day, when demand dips, is its stomach (which has deepened over time as extra individuals have adopted rooftop photo voltaic). The ramp up on the finish of the day kinds the duck’s neck earlier than really fizzling out within the night to type the duck’s head and beak.

What causes the duck curve?

The form of the duck tracks vitality demand all through the day, with peaks at first and finish of the day however a deep valley in between. The motive the stomach of the duck is getting deeper is that extra and extra renewable vitality (together with photo voltaic) has come on-line. This considerably reduces the load that utilities must take care of through the day, when the solar is brightest and photo voltaic vitality manufacturing particularly is highest.

Why the duck curve issues

As extra photo voltaic vitality comes on-line and the duck curve deepens, it presents two massive challenges to utilities, in line with the EIA: grid stress and economics. 

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“The ramp up is a big problem — figuring out what to turn off in the middle of the day when there’s too much power is a problem,” McCalmont mentioned.

The points are worse within the evenings, when demand for vitality is excessive however there’s much less photo voltaic to depend upon. This shift causes standard energy crops to shortly ramp up electrical energy manufacturing to match the vitality calls for of their prospects. The economics subject offers with the truth that vitality crops now have extra competitors. As photo voltaic fulfills many individuals’s vitality wants, crops needn’t function at full capability, resulting in diminished revenues.

“If the reduced revenues make the plants uneconomical to maintain, the plants may retire without a dispatchable replacement,” the EIA mentioned. “Less dispatchable electricity makes it harder for grid managers to balance electricity supply and demand in a system with wide swings in net demand.”

How rooftop photo voltaic impacts the duck curve

As extra photo voltaic vitality comes on-line and the duck curve deepens, it presents two massive challenges to utilities, in line with the EIA: grid stress and economics. 

“The ramp up is a big problem — figuring out what to turn off in the middle of the day when there’s too much power is a problem,” McCalmont mentioned.

The points are worse within the evenings, when demand for vitality is excessive however there’s much less photo voltaic to depend upon. This shift causes standard energy crops to shortly ramp up electrical energy manufacturing to match the vitality calls for of their prospects. The economics subject offers with the truth that vitality crops now have extra competitors. As photo voltaic fulfills many individuals’s vitality wants, crops needn’t function at full capability, resulting in diminished revenues.

“If the reduced revenues make the plants uneconomical to maintain, the plants may retire without a dispatchable replacement,” in line with the EIA. “Less dispatchable electricity makes it harder for grid managers to balance electricity supply and demand in a system with wide swings in net demand.”

Solutions to the duck curve

The duck curve might current challenges to utilities, however the answer is laying in wait: battery storage. Rather than simply having that extra photo voltaic be fed again into the grid when it isn’t wanted, it may very well be saved in batteries to be deployed at a later time.

“If you have storage and can shift that peak time by just a few hours, that certainly helps the duck curve,” McCalmont mentioned. “Take that excess solar in the middle of the day, instead of turning it off, put that energy into a battery. Then at 4 p.m., when you need that energy, discharge the battery to meet that ramp. That’s a win-win for everybody and helps smooth out the curve.”

This idea of utilities leveraging saved vitality is named a digital energy plant. Basically, as an alternative of counting on a single supply of vitality era — a pure gasoline plant, for instance — the utility can leverage a mixture of vitality sources. That plant might play a half, however so will close by photo voltaic and wind farms in addition to residential photo voltaic and batteries. This approach, the utility is healthier ready for a ramp up in vitality demand with out the traditional plant struggling to generate all of the wanted vitality, and there will not be main disruptions in service if one vitality era methodology experiences setbacks.

What’s holding this idea again is the necessity for extra battery storage. Solar batteries are costly at this second — virtually as expensive as a photo voltaic panel system itself — so many owners with photo voltaic merely haven’t got them. Utilities might begin subsidizing them within the close to future, however that may require laws to be drafted to permit them to take action. California, for its half, is not ready.

“Battery storage is swiftly being constructed in California; it’s grown from 0.2 gigawatts in 2018 to 4.9 GW as of April 2023,” in line with the EIA. “Operators plan to build another 4.5 GW of battery storage capacity in the state by the end of the year.”