When William Shakespeare wrote Love's Labour's Lost , he would have used light

from tallow candles at a cost (today) of £12 000 per million lumen-hours. The

same amount of light from electric lamps now costs £2, while the supply of

artificial light in the country of Shakespeare's birth has increased 350 000 times!

But this illumination has a dark side. Globally, lighting consumes more electricity

than is produced by either hydro or nuclear power and results in CO₂ emissions

equivalent to two-thirds of the world's cars.

A standard incandescent lamp may be much more efficient than a tallow candle,

but it is far less efficient than a high-pressure sodium lamp. Were inefficient light

sources to be replaced by the equivalent efficient ones, global lighting energy

demand would be up to 40% less at a lower overall cost. Larger savings still could

be realised through the intelligent use of controls, lighting levels and daylight.

But achieving efficient lighting is not just a question of technology; it requires

policies to transform current practice. This book documents the broad range of

policy measures to stimulate efficient lighting that have already been

implemented around the world and suggests new ways these could be

strengthened to prevent light's labour's from being lost.