Uses for 1 year old diesel fuel?

Fishhead is right - algae won't grow without sunlight, but mold and bacteria will, which are the more likely organisms growing in diesel fuel either way.

In any case they shouldnt be a problem on something thats only a year old.
Just outa curiousity what do you think powers most standby generaters?
The statement that the tanks are almost full makes it very likly the fuel would be fine.

Then you had something in the container besides diesel fuel.

Diesel fuel, unless contaminated, will NOT go bad in a year.

guess its nice to have an old tractor heck Ive ran 6 year old gas though my old allis and a mix of 3/4 gas 1/4diesel before .
If your that worried about it use it to kill weeds or start fires
myself I'd look into getting a genny hooked up to one of the engines and burn it there
Of course being a tinkerer Id consider finding an old tractor and putting one of the engines in it , or making a saw mill . hate to think of an old diesel going to waiste

I regularly pump out OLD furnace oil (demolition houses) and burn the fuel through my machines. I would bet that in many cases the fuel is YEARS old.

Diesel doesn't go bad, heating oil even less so. That said, I do run some pretty heavy duty filters on the outlet of the pump. Dirty fuel doesn't help anything.

Pete