Solar panels over water are still not rendered on top of the water despite using layer=1 tag - see topic on old help.osm or an example on osm map. If the OSM Carto freaks could find some time and have a look ?!
I think this is probably the same as this issue which I’ve just commented on.
As already mentioned in the first link here, layer
doesn’t work in this way - it can only sort things that are rendered together. Especially where a lot of things are being rendered, as in OSM Carto, there are multiple layers of rendering.
Power plants/generators are rendered early alongside other landuses, and so floating solar generators will be overridden by water layer.
This is the relevant issue.
Here is a solar farm that does get rendered on top of the water: Way: Zonnepark Kloosterhaar (915205866) | OpenStreetMap
Current screenshot:
Maybe the floating=yes
makes a difference?
The reason this solar farm renders is because its an inner of the water relation. This implies there is no water underneath the solar farm though, so this is a bit questionable.