background
bright
bulb
conservation
eco
ecological
ecology
economic
economical
economy
efficiency
efficient
electric
electrical
electricity
energy
environment
environmental
equipment
fluorescent
glass
glowing
illuminate
illuminated
illumination
improvement
invention
isolated
isolation
lamp
lightbulb
lit
lumen
luminary
luminescence
luminosity
luminous
modern
object
orange
powerful
save
saver
single
technology
tube
twist
white