Sky lapse in two tone (opens in new tab)

Calm water surface is a specular scatterer, meaning radar energy will be reflected away, and proportionally so as the incidence angle increases.

Images collected at lower incidence (closer to nadir) might feature very bright surface water if it is calm, as more energy is reflected towards the radar.

Rough water surface is a diffuse scatterer, and will generally appear brighter than calm waters.

The liquid water absorbs most of the radar wave (at least for the C band, as is the case of sentinel-1). Thus, in the images it appears natively "black". When there are a lot of waves, the surface of the water forms some spurious reflectors that appear as a light texture in the surface, but the signal is definitely less powerful than metal/concrete reflectors of buildings and ships. Notice that in the "Humber" image of TFA you can appreciate some texture in the water. The contrast in this image has been exaggerated a lot, which saturates most of the land.

They're composite images, so there's definitely some post-processing going on. The sea surface will show up darker, but SAR is sufficiently sensitive to to detect oil slicks.

You pretty much answered your own question: compared to the size of the coast, the amount of energy these wind farms capture is negligible. You might see a reduction of power if you built a dense farm up and down an entire coast, but even then, the ocean is big compared to these farms.

Edit to add: the Hornsea wind farm featured in this article is 2.5 GW and about 400 sq miles. [0]. The total energy capacity of existing generation assets is on the order of 7,500 GW [1]. Let's double that, so 15,000 GW, which would be about 2,400,000 sq miles. There's 1,015,756 linear miles of coast [2]. We know Hornsea is roughly square, so a 20 mile deep set of turbines doesn't interfere with each other, so that gives us ~20,000,000 sq miles of usable coast for wind, and again, if we double the existing electrical generation for the earth, we'd cover 2,400,000 sq miles. (obviously not all of that is usable, but we're talking orders of magnitude here) There's really no conceivable situation where we'd build enough wind farms to interfere with each other.

[0] https://en.wikipedia.org/wiki/Hornsea_Wind_Farm

[1] https://www.statista.com/statistics/267358/world-installed-p...

[2] https://en.wikipedia.org/wiki/Ocean

A maximum of 60% of the winds power can be extracted from wind (Bet'z law [1]) and modern turbines are only capable of catching 80% of that. There's lots of research in optimal spacing.

I read that a rule of thumb was 4-5 diameter widths between turbines at right angles to prevailing wind and then 7 diameter widths between rows facing the wind

[1] https://en.wikipedia.org/wiki/Betz%27s_law

Wikipedia has a short paragraph on the topic with some references for more details: https://en.wikipedia.org/wiki/Wind_farm#Turbine_spacing

I don't have the answer handy, but I do know there is a ton of research that goes into wind farm optimization. Location of the towers, cost to build, etc.

I am curious how much small elevation differences impact optimal positioning of turbines, as that is a non-issue with offshore wind. The turbines in land-based wind farms are not in a nice grid like the offshore wind farm. https://openinframap.org/#9.68/41.6112/-92.4971

The excerpt from an abstract below mentions the wake turbulence can cause other turbines to shut down.

"...The distance between the turbines is among other things dependent on the recovery of wind energy behind the neighboring turbines and the increased wind load. Models for the mean wind speed and turbulence intensity in wind turbine parks are considered with emphasis on modeling the spatial correlation. Representative limit state equations for structural failure of wind turbine towers are formulated. The probability of failure is determined taking into account that wind turbines are parked for wind speeds larger than 25 m/s resulting in reduced wind loads. An illustrative example is presented where illustrative models for the spatial correlation is taken into account"

https://www.tandfonline.com/doi/full/10.1080/102866006011566...

That's because ocean PV is... unrealistic; the wear and tear on these things is immense. I am guessing windmills are affected less, with the blades being made out of fiberglass and most of the construction being above the waves.

Source: I made it up, I'm a software engineer not a maritime power expert.

Here's a site that does live tracking of ships:

https://www.marinetraffic.com/en/ais/home/centerx:1.7/center...

"Since December 2004, the International Maritime Organisation (IMO) requires all passenger and commercial vessels over 299 Gross Tonnage that travel internationally to carry an AIS transponder that include a GPS receiver which collects the vessel's position and movement details."

Counting across the longest segment of ships at the narrowest point of the English Channel in the feature article I see about 18 ships. In the live image from marinetraffic I see about 8. So even though the feature article is a composite image, the English Channel is indeed pretty crowded.

These are composites, although it's not clear exactly how many images are composed to build the final view.

To quote the article:

> Inspired by some similar images shared by Tim Wallace in 2020, we’ve created a series of black-and-white composite renderings of some of the points of flux in the global energy system. Created in Google Earth Engine, these pictures are effectively annual timelapse images based on Sentinel-1’s radar, consisting of multiple snapshots taken by the satellite across 2023.

Not sure if the wind farm images are also composites (wouldn't make a lot of sense), but those of shipping lanes definitely are...

Those are composite renders, integrating over time, not a snapshot.

> Created in Google Earth Engine, these pictures are effectively annual timelapse images based on Sentinel-1’s radar, consisting of multiple snapshots taken by the satellite across 2023.

You can look at Marine Traffic to get a better sense of now versus the composites in the article.

The English channel is apparently busiest shipping lane in the world, so it’s not surprising that it looks so busy on these images.