atom
atomic
barrel
battery
building
bulb
coal
dam
eco
ecology
electric
electricity
energy
environment
factory
fuel
gas
green
house
icon
industrial
leaf
light
lightening
line
nature
nuclear
oil
outline
panel
petroleum
plant
plug
power
refinery
renewable
science
set
sign
socket
solar
station
sun
symbol
tower
transmission
turbine
valve
wind