Wattage is not exactly proportional to lumens (a measure of brightness). A single 150 watt incandescent bulb is rated at 1500 lumens, or 1700 lumens, 1750 lumens, or 2450 lumens, or 2740 lumens, depending on the make and model, and that's the initial lumens. The brighter two are normal life (750 hours), the dimmer ones are long life.
A 75 watt incandescent might be 700 lumens, or 790 lumens, or 850 lumens, or 530 lumens (long life).
Energy consumption is directly related to the wattage, so one 150 watt bulb takes as much power as two 75 watt bulbs. But the 150 watt bulb might be as bright as three 75 watt bulbs (more efficient).
If you are concerned about energy, the 18 watt CFL advertised as 75 watt replacement says it has long life (10000 hours) and 1200 lumens initial brightness (more lumens per watt). But it costs 10 times as much.