against

background

black

blue

bright

cable

construction

danger

electric

electrical

electricity

energy

engineering

environment

equipment

farm

green

high

image

industrial

industry

landscape

light

line

metal

motion

natural

nature

network

orange

plant

pole

power

pylon

silhouette

sky

slow

steel

structure

sun

sunrise

sunset

tall

technology

tower

transmission

tree

volt

voltage

watt

wire