London’s move to become the first city with streets illuminated fully by light emitting diodes (LED) by 2012 is a heartening sign that this semiconductor lighting technology is attaining critical mass. Four LED-based lighting projects were unveiled in the British capital recently, and 10 more are under implementation this year. Increasing greenhouse gas emissions from power generation have prompted many cities around the world to shift from conventional lamps to LEDs for public lighting. Traffic lights were converted first, and the automotive industry adopted it for car and motorcycle tail lights; better technology to produce white light now makes street lighting possible. Austin, Raleigh and Ann Arbor in the United States and Toronto in Canada have embarked on a plan to become ‘LED cities.’ This is a pioneering step considering that LED technology is undergoing constant refinement. But benefits like saving on power costs, compared to even compact fluorescent lamps, and longer life of the infrastructure make a good case for the changeover. An early switch to LEDs and the newer Organic LEDs for lighting and display applications should therefore appeal to cities and towns. Beijing is impressed and the forthcoming Olympics will showcase state of the art LEDs. The fast-paced adoption of green lighting technology should excite Indian cities. Mumbai and Delhi can be early movers as they are part of the Clinton Climate Initiative, which is promoting high performance technologies for lighting.

Cool and energy-efficient lighting made possible by the LEDs is important to emerging economies such as India. Environment-friendly LEDs can help light up rapidly urbanising areas while slowing growth of carbon emissions. The technology meets the efficiency bar that former United States Vice President and climate change crusader Al Gore advocates; India can use it to leapfrog the ‘dirty’ phase of economic growth witnessed in the West. When connected to solar power, LEDs can deliver off-grid lighting to remote areas. What is more, the best is yet to come. Like Moore’s Law for computer chips, there is Haitz’s Law for the LEDs which, according to Nature Photonics, states that every 10 years the amount of light generated by an LED increases by a factor of 20, while the cost per lumen (unit of useful light emitted) falls by a factor of 10. Disappointingly though, with all the promise, India has not built a strong manufacturing base for advanced LEDs, while China has. Attracting investment in this important sector, which has an estimated annual market size of $15 billion, has to be a priority.