It is so simple I'm amazed no one has mentioned it before now. A new type of fencing that is not only a barrier but a fortification. It would be more costly to produce in both materials and costs but also be more durable.
Electric fencing would act as a defensive structure to keep the xenos (or bugs as I affectionately call them) out. When connected to a power source (battery or power core) it would provide damage to things that come into contact with it similar to magma or bile blocks, with the obvious difference of being powered by electricity.
I think it'd be relatively simple to add and would be a great addition to the game by introducing another defensive structure to use. It'd be especially useful for claims.