Reducing the brew is the most time- and energy-consuming process.

It has just occurred to me to put a fan to blow over the pot to speed up the process and make it less energy intensive. Has anyone done that and noticed a difference?

I'm assuming any DMT will not oxidize as it's in salt form.

Whenever reducing liquid I've used fans,
Never brewed Aya, but a fan will def speed up evaporation

How would you save energy by adding the fan electricity?

I would expect it might evap a little faster, but you certainly would use more power that way if that is a concern. I also wouldn't expect any impact on the leaf alks one way or another--

I think he meant time spent, physical/mental energy used,

Obvi using a fan isn't going to use less electricity

For sure--

If the fan makes the evaporation more efficient, the cooker will use less energy.

The fan itself uses energy too, but it's negligible compared to what the cooker uses. Like 20 watts vs 1500 watts. If the fan cuts the evaporation time by half, that can be X hours * (1500 W - 20 W) of electricity saved.