I was thinking of a 20 KW size also - having seen the projected / possible loads; however, just what will be running at the same time?
Also, the thought of a 20 KW Genny coupled to a 30 HP Prime Mover is - in simple terms "Tim Taylor Overkill" for a small Residential setup!
Not that it wouldn't be cool! I would do it, but I also have a "touch of the 'ol Tim Taylor" in me!
The Neighbors would just love hearing that 30 HP Diesel Prime Mover chuggin' all night long!
(I would most likely use a Diesel Prime Mover - once again, the "Tim Taylor" Syndrome
... although, a Gasoline Prime Mover would be fun too!).
Hefner (as in Hugh Hefner - Playboy Magazine) has two standby gensets at the "Playboy Mansion West" (Belair, CA).
The original first one is a 750 KW Diesel Genny.
The newest is a 1 MW or 1.5 MW Genny.
These get plenty of use during the Raging Parties thrown at the place!
The PoCo cannot upgrade the original 4160 VAC Primary Feeders (something like a 100 amp circuit???), so when the KW load in this area gets high (and corresponding Party-Personnel get high
... ), the Breaker trips at the yard, leaving the customers Sans Ready Killowatt!
(Credits to Virgil, for the "Sans" term!)
Now when the breaker trips, everyone else loses power, but Party keeps on Raging!
All thanks to Standby Gensets!
This story, along with others, are more indepth and kind of interresting!
Maybe sometime when I have an urge, I'll post more about the Mansion.
Sorry, no naked women stories!