My immediate family has a plan of a survivalist camp. More than outdoor survivalist things, but planning to survive modern potential catastrophes. Not finding one on-line like it I attempt here to describe our objectives.
I've been playing with LED emitters from surplus distributors like Electronic Goldmine. A small LED light about 1 cm square and flat as paper lights up a room like a 60 Watt incandescent bulb. It consumes about 10 or 20 Watts (9 to 12 Volts at less than 1 Amp). Once you add a heat sink and maybe a fan the size increases of course.
10 Watt can run on as low as 9 V and only draw about 1/2 Amp. At 12 Volts it draws about 1.5 Amps and is twice as bright.
20 Watt emitters draw over 1.5 Amps at 12 Volts, but it is about the same brightness as a 100 Watt incandescent bulb.
A good design includes a current regulated power source. I have been running them off of a regular wall wart power supply for years with no problems. I don't expect to get 100,000 hours out of them, but I don't expect to get 100,000 hours out of me either.
The biggest LED assembly I have is rated at 6,000 Lumen and runs off of 120 V line power. The original purpose was exterior building lighting.
Very low power! Comes in various shades of white from about 3,000 K ("warm white") to 6,000 K ("cool white"). My biggest complaint is that single light sources make a pretty dominate shadow. The assembly I made for my wife's sewing machine has two light sources about 2 feet apart and leaves no shadow. 5,000 K is suggested for sewing for truer color representation. Under 3,000 K white cloth looks yellowish.
How big a heat sink and fan? I use what I had on hand. Heat sinks and fans were salvaged from junked computers and TVs. A 10 Watt emitter still warms up a 160 square inch (surface area) heat sink running at 12 V, but stays cool at 9 V.. A fan was added running at 12 V and it runs suitably cool.
I also have a 20 W emitter on a heat sink of about 30 sq in and a tiny (40 mm) fan and it runs cool. So your guess on engineering is probably better than mine. I'm just a technician.