An immense amount - possible derived from the amount you can get in a shed - or the description of the amount of crap that covers the road (almost specifically designed to kill motorcyclists) when a lorry sheds its load.
Originally heard as Royal Marines slang.
"What do you fancy doing tonight?"
"I dunno, but Bomber has got a fucking shed load of vodka in his fridge and Sally has just got a copy of the porn movie she starred in"
Euphemism in South Africa for rolling blackouts. "Load shedded" is also used facetiously in South Africa to refer to any device that is currently not on or not working.
"Sorry my left back tail light is not working officer. It is currently being load shedded"
"You won't be able to contact me on my cellphone as my battery is load shedded"
"I can't think right now, my brain is being load shedded!"