Hint below this, only look at it if you really have no clue how to win and have tried several times. Maybe this will ward off some 1/10 ratings, maybe it will not.
Spoiler
Try to distract some of the spores so that they hit parts of the map that you can repair without too much problems. You can't defend all areas, but if you free the AC emitter from it's counterpart you have a decent AC source against these annoying spores. Only use beams where spores could cause long term damage, like at reactors.
This is actually pretty hard with low energy, but it is sure possible. After all, I was able to upload it.