A method, apparatus, and system for compensating for lamp lumen
depreciation. The method includes operating the lamp under rated wattage
for a period towards the first part of operating life of the lamp.
Operating wattage is increased at one or more later times. Energy savings
are realized. The increases also restore at least some light lost by lamp
lumen depreciation. The apparatus uses a timer to track operating time of
the lamp. A few wattage changes made at spaced apart times can be made in
a number of ways, including changing capacitance to the lamp, or using
different taps on the lamp ballast.