Solar easement is like a promise that a landowner makes so that the sun can still reach their property. It's kind of like a special rule that we make so that the sun will still shine on our homes and the things around it, even if the owner of the land next door builds something tall. Here's an example:
Let's say you own a home and you have a nice big garden. One day your neighbour decides to build a bridge, and it's really tall. That could block out the sun from reaching into your garden and make it so your plants don't grow as well. That's not fair for you because you need that sun to help your garden, so you might ask your neighbour to sign a solar easement agreement. That way, the bridge won't be able to block out too much sun from your garden, and your plants will still be able to get enough sunlight.