Shadecloth is a woven material that blocks most (not all) sunlight. It is rated by the amount of light blocked, so 90% shadecloth blocks 90% of the light (durrrr….). It can help keep direct sun off folks who need to park in full sun to make power.

Advantages

• can be lighter than a tarp
• less affected by wind because some can pass through
• allows more breeze for the same reason
• quieter than a tarp

Disadvantages

• more expensive than a normal tarp
• somewhat more bulky due to woven material

This pic shows what it looks like under shadecloth when in use. You can see the full sunlight (overexposed area), full shade (under the van) and the 90% blocked sun under the shadecloth.

If you look carefully you can also see full shade in the photographer's shadow, and on the edges of the shadecloth where the material is solid. Bonus: there is a dog in the shadows under the van.