They are not really good at “Energy Droughts.”
https://www.pnnl.gov/news-media/energy-droughts-wind-and-solar-can-last-nearly-week-research-shows
December 11, 2023 | News Release
“Energy Droughts” in Wind and Solar Can Last Nearly a Week, Research Shows
Understanding the risk of compound energy droughts—times when the sun doesn’t shine and the wind doesn’t blow—will help grid planners understand where energy storage is needed most
Solar and wind power may be free, renewable fuels, but they also depend on natural processes that humans cannot control. It’s one thing to acknowledge the risks that come with renewable energy: the sun doesn’t always shine and the wind doesn’t always blow, but what happens when the grid loses both of these energy sources at the same time?
This phenomenon is known as a compound energy drought. In a new paper, researchers at Pacific Northwest National Laboratory (PNNL) found that in some parts of the country, these energy droughts can last nearly a week.
“When we have a completely decarbonized grid and depend heavily on solar and wind, energy droughts could have huge amounts of impact on the grid,” said
Cameron Bracken, an Earth scientist at PNNL and lead author on the paper. Grid operators need to know when energy droughts will occur so they can prepare to pull energy from different sources. On top of that, understanding where, when, and for how long energy droughts occur will help experts manage grid-level battery systems that can store enough electricity to deploy during times when energy is needed most.
The team published the findings October 31 in the journal
Renewable Energy and will be presenting at this week’s annual meeting of the American Geophysical Union.
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Here in “Upstate” New York, PV solar output in the Winter is less than half what it is in the Summer. Between fewer hours of daylight and less intensity, there’s too little solar energy hitting the ground (that’s why it gets cold outside.) It’s these seasonal fluctuations which concern me more than the diurnal cycles. If we’re heating buildings with electricity, and there’s less available when we need it most, that’s a problem.
Another thing which concerns me about the use of Lithium-ion batteries for leveling diurnal fluctuations is their “cycle life.” A solar panel which may last 3 decades or more, might need to have its battery backup replaced several times.
https://cmbatteries.com/complete-guide-to-lithium-battery-shelf-life-cycle-life-and-calendar-life/#what-is-the-cycle-life-of-lithium-ion-battery
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What is the Cycle Life of Lithium-ion Battery?
The cycle life of a lithium-ion battery refers to the number of charge and discharge cycles it can undergo before its capacity declines to a specified percentage of its original capacity, often set at 80%. This metric is particularly important for applications where the battery is frequently cycled, such as in electric vehicles, power tools, and
energy storage systems.
A complete cycle occurs when a battery is fully charged and then discharged. Even partial cycles (charging or discharging only partially) contribute to the overall cycle count. As the battery ages, these chemical reactions cause wear and tear on the electrodes and electrolyte, leading to a gradual decrease in the battery’s energy capacity in our article “
Understanding the Life Cycle of Lithium-Ion Batteries”.
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