You guys are forgetting that he may not want 100s of gallons of diesel nor may he beable to use it in a timely manor. 20days with out power is not normal any where in this country so having 250gal of diesel sitting around may be more of a liability than a benifit.
If you can get diesel in an outage why not have the storage capacity clean/ready.
Well...since our local power outage that began on Feb 25, 2019 there are still thousands without power here in Oregon. They are now on day 10+ without power due to a record breaking winter snow storm that has left some of the more remote roads still impassible due to downed trees and snow drifts so they can't even get out to get fuel.
https://www.opb.org/news/article/oregon-douglas-county-snowstorm-power-outage/
Local news reports that there were approximately
2,000 trees downed in this storm across just one road, Hwy 58, that cutoff all access in/out in Oakridge, OR for several days and the few gas stations were running low on fuel. So you can't always count on the option to drive out and obtain fuel during an extended power outage event.
https://www.opb.org/radio/programs/...regon-oakridge-residents-snow-winter-weather/
So the lesson many learned is to be better prepared for the unexpected (Generator + adequate fuel).
Since the OP lives in Michigan, obviously severe winter storms are not out of the question plus anything else that might cause a widespread pwr outage. Since he has a MEP-802 he should be prepared to run it for several days. With a burn rate of ~.5+ GPH, if he were wanting to run it 12 hrs per day during an outage and wants to be able to run for a week without going out to get fuel, one would be wise to store approx. 50+ gallons in addition to a full genset day tank. If its necessary to run 24/7 then double those numbers.
When diesel is stored properly and treated I have had diesel keep for 4 yrs before using and it still performed very well. If a genset is run for test PM runs for an hour a month, some of that fuel will get burned and replenished. If his fuel reserve were stored in Jerry cans its easier on a month-to-month basis to use a Jerry can to top up and then fill that can with fresh diesel and tag it with a date code so only oldest fuel gets burned first. Its also easier to keep individual Jerry cans full and air tight vs vented bulk storage. However, bulk fuel storage is much easier to manage overall ESPECIALLY during an extended outage. So there are trade-offs involved.
With those caveats, you're right about it coming down to a personal choice of how one wants to manage reserve fuel storage.
If he has any neighbors with diesel vehicles or equipment he might be able to work a fuel rotation deal of sorts if he should desire to turn his fuel reserve over more frequently.