"Everyone" Knows That Wind and Solar are Complementary
"Everyone" is wrong
The below post is wrong. I have written up a corrected post here. I created a new post rather than marking/correcting this one because the fundamental premise is wrong.
I post all of my detailed posts on reddit first for review. I think it’s every bit as good a review as one would get from an academic presentation - and it’s a lot faster (and blunter).
Once again I had someone comment that I need to take the fact that wind and solar are complementary. That the wind blows more at night. Once again the comment was that “everyone know this.”
The problem is, nope.
Here’s the PSCO (most of Colorado) generation for the last month.
And here it is the the Northwest region (which includes Colorado)
Going with the entire NW it evens it out a little. Not much help to Colorado at present as we don’t have much spare capacity to the rest of the NW region. But we can build to get to that.
The thing is, there is no pattern to the wind vs solar generation. On Feb 11 they both spiked during the day. The night of Feb 12 the wind was at its lowest. There really is no pattern between the two. And poor Colorado at present - Feb 18 there was no power from either for a day.
So can we please stop saying “everyone knows that wind & solar are complementary?” At lease until someone can, you know, prove it?
And proof is not some study that says they are complementary,1 proof is data of actual generation for some region. Where looking at a couple of random months for that region show that in actuality they are complementary.
Update: On reddit the user Sol3dweller provided links to 8 research articles (see here) discussing the inverse correlation between wind & solar. From reading these studies it looks like wind & solar has a strong inverse correlation when the land is next to the ocean, sea, or very large lakes (the Great Lakes). I can see large amounts of water impacting the wind speed as the water is a giant heat sink.
There is also a small but measurable inverse correlation in many (not all) other places. I'll grant you that looking at the graphs I displayed, they will not make obvious a 10% inverse correlation. The wind can be both generally irregular and still be a bit inversely correlated.
I’m revising my statement to be “In some places there’s a strong correlation between wind & solar while in most places the correlation is small to nonexistent.” In addition, it’s a correlation, not an absolute.2 So you still need backup to handle when there’s no wind or sun. You just won’t run the backup as often.
I have seen way too many studies where their conclusions are suspect to accept the conclusion of a report. Not when it’s very simple to view the raw data.
No solar at night is an absolute.
As a lifelong sailor, there are plenty of shoreline places where wind and solar are positively correlated.. It's called a sea breeze. The sun heats up the land. more than the water. The air over the land rises and the cooler air over the water is sucked in. Insome places such as Corpus Christi you can set your watch by this process. In Perth, Australia, it's called the Fremantle doctor. The same process can happen inland. The Columbia River Gorge is an example. In all these places, race committees know there is little point inscheduling a race before 10AM or after 5PM.
The inverse process overcooling of the land at night does happen creating a shore breeze
which genreally peaks just before dawn. But in my experience, this phenomenon is rarely nearly as strong as the sea breeze.
This graph is misleading. It measures solar PRODUCTION vs wind PRODUCTION. To really assess whether wind and solar are complementary (sic) you need to graph hours of adequate sunshine and hours of adequate wind, scaled by the areas that are feasible for solar and wind production respectively.