The correct explanation for how compact fluorescent bulbs can produce as much light as incandescent bulbs while using less energy is that fluorescent bulbs produce other forms of energy, too, including heat.
Incandescent bulbs primarily generate light by heating a filament, which also results in a lot of heat waste. In contrast, compact fluorescent bulbs use a different mechanism that is more efficient, producing light through a chemical reaction that emits less heat and therefore uses less overall energy to provide the same amount of light.