[xfitm3]

Don't forget that a substantial amount of fuel is burned while parked. Lights and other electronic equipment consume a lot of energy.

"In one recent report about police vehicle fuel consumption, the cruiser studied was found to idle 60% of the time during normal operation and used 21% of its total fuel while parked. While the engine provided 250 horsepower (hp), together all of the accessories needed less than 2 hp. (Air conditioning consumed the most power, followed by external lighting.)"

https://afdc.energy.gov/files/u/publication/idling_emergency...

[geomark]

Didn't read the article, but the engine doesn't provide 250 hp while parked and idling, that's for sure. Certainly it is inefficient compared to an engine sized to provide 2 hp but that's not the same as running it at max rated power.