Thousands of light bulbs (sprite batching/instancing)

Hello, I want to implement night city fake lights like this: http://www.adriancourreges.com/img/blog/2015/gtav/b/01_bulb_after.jpg
http://www.adriancourreges.com/img/blog/2015/gtav/b/02_bulb_depth_test.jpg

As for now using material billboards but they destroying performance.

Any ideas?