There's a rough 25% efficiency for human work and this is conveniently the conversion of kj to kcal so if a PM reports 2000kj you can basically say that's 2000 cals. Something like that. I basically eyeball the kj number in WKO and that's my cals used.
That doesn't sound right. I know I'm big but I'd do 3-500kcal in 30min. I'd expect 2500-3000 for 100k.