I have the log here http://pastebin.com/5J8rjuAY
I started my server today and I cannot seem to get to the one turbine I built. I was the largest sized turbine I could build and it was full to the max with steam and stored power. When I move towards it now I get that crash and can no longer join my game. The server doesn't crash just the client.

I tried removing fastcraft and optifine and it still crashes.

Added a null check, thanks!