Just had this issue occur to me midway through a save. It was in fact a temporary issue with the discord overlay. I opened the overlay (shift+`) and closed it, and the issue stopped. I'm not sure what triggered it to start misbehaving.

Thanks for responding. For a normal laser turret, the power spikes up to 9.6MW briefly on each shot as the buffer recharges, the devs have stated this previously when the same issue was posted. The average power draw over time is accurate to the tooltip.

Now that there are higher quality turrets ...

Laser turret max consumption is misleading and Space Age makes the problem worse.
This has been reported before many times: https://forums.factorio.com/121161 https://forums.factorio.com/viewtopic.php?t=102287
The answer is always "not a bug" "deal with it" "buffer recharge" "accumulators ...