CFLs use about one$-$fifth of the $...$ of a comparable incandescent light, and were until recently the available in $...,$ and last about six times longer.

a$.$ demand; energy; buildings

b$.$ energy, standard light; homes

c$.$ renewable sources; energy; development

d$.$ energy savings; efficiency units; homes

Coal $...$ require$/$s large quantities of water, mainly for their cooling systems; cooling system $...$ varies$/$vary greatly depending on the design with "wet" $($evaporative$)$ systems having the highest and "dry" systems the lowest water requirements per unit of

a$.$ combustion; electrostatic precipitators; atmosphere produced.

b$.$ power plants; combustion; high$-$pressure produced.

c$.$ power plants; water requirements; power produced.

d$.$ electrostatic precipitators; large stockpiles; life cycle produced.