Ronan,
I build my storage cupboards from 3/4 plywood (easy to fix shelves and drawers)….my small tool cupoard is 2'x2'8'high…..a cupboard 8'w x 2'd x 6"high would need two bulbs……..
top shelf used only for tools I can't just throw away……anyway, protected against knocks in the bottom of the cupboard is a bulb holder with a 100w equiv curly wurly saver bulb that is on 24×7 from late Sept – late March……
the shelves are made an inch shorter than the depth of the cupboard and fitted so the 1 inch gap is staggered front to back….so, first shelf the gap is at the back then the second is at the front, etc etc…..with the door shut except when working my cupboard stays at +5 to +10degrees depending on the outside temp……(My workshop is a draughty un-heated barn in a converted water mill) and we reg get minus 8's, all the heavy stuff is in the bottom 4jaw's etc, above that the drawers contain files, assorted hand tools (spanners etc) 3rd drawer has all taps and dies and then the turning tools bit…then the measuring stuff…..the next shelf is where it gets interesting…it contains antique irriplaceable American workshop manuals for cars….dread to think of the value but as I use them very often or they'd be in the house…..they are kept in perfect condition, nice and dry no colored spots on the pages etc etc………
the elec usage is minimal, especialy when the rust is kept at bay…..
it works for me, (now in my 13th year), easy and quick to build, spose u could paint them or even use MDF but I like my oil ingrained effect on the exterior………
good luck….. Clogs