Why the future is bright for LEDs

Photo: Nasa GSFC

The lighting industry has changed significantly over recent years thanks to LED technology. Its long life, low carbon emissions, efficiency and quality of light have helped it gain an ever-growing market share.

The Electronics and Optoelectronics Research Laboratories at the Industrial Technology Research Institute has suggested that the global LED lighting market value was worth $30.5 billion (£20.3 billion) in 2014 and will increase to $51.6 billion in 2018. Clearly it has a bright future, but it is a constantly evolving market that is set to see further significant changes over the next few years as the technology matures.

LED lighting is on the radar of everybody from homeowners to multinational corporations”

In the early days, the biggest barrier to widespread adoption of LED lighting was its price. This changed in 2012 when increased competition and lower production costs resulted in improved return on investment.

At present, most LEDs offer an average of 115 lm/W, yet some manufacturers have already demonstrated the capability to produce 200 lm/W sources, which need less than 5W to produce the same amount of light as a traditional 60W incandescent lamp.

Some manufacturers say their products could last up to 100,000 hours, based on design and operating temperature. Such claims about product lifetimes are now under scrutiny and independent testing will separate fact from fiction.

The ‘life’ of an LED is the period after which the luminaire emits only 70 per cent of its original output. This L70 rating is a measure of lumen maintenance, the term used to measure the light produced by a light source at a certain point in the future when compared with its output when new. If a light source emits 1,000 lm when new and 700 lm after 60,000 hours of use, it has a lumen maintenance of 70 per cent at 60,000 hours. In other words, it has an L70 of 60,000 hours. L70 is used because the human eye cannot detect the difference until output has declined by 30 per cent.

Interchangeability of LED lighting products will be important in the years ahead, and the Zhaga consortium is leading the way. Its members include hundreds of companies from around the world and it is developing specifications that will enable users to replace LED light sources from one manufacturer with those from another. In December 2014 it signed a liaison agreement with the International Electrotechnical Commission to help define standards in this area, and it should be published over the next few years.

This is a positive step, but the lack of recognised and enforced standards has resulted in a dramatic variation in the quality of products on the market. One of the biggest problems has been the proliferation of low-cost and poor-quality lighting products from China. These products usually have poor colour rendering – an indication of the way objects will appear under the light source, on a scale from 0 to 100.

In September 2013, a European eco-design regulation, DIM2, came into force and LEDs with a CRI below 80 are now banned from sale in Europe. DIM2 sets minimum performance requirements and has created a more level playing field by banning low-quality lamps from the market. LED luminaires sold on the European market should, by law, also carry the CE mark, which is a statement by the manufacturer that the product complies with all relevant EU legislation, including product safety standards and directives. As the market matures, the amount of low-quality products should diminish further.

Marcus Brodin is commercial director at Future Energy Solutions

With LED lighting becoming mainstream, the next generation of solid state lighting technology is already creating interest. Organic LED lighting works by passing electricity through one or more thin layers of organic semiconductor material. Mass-market adoption of OLED lighting is not expected to occur for at least two years, but it is already being used in TVs and phones.

The return on investment argument for using LEDs involves a number of considerations including energy, maintenance, life, colour quality, colour consistency and using best available technology. However, LED lighting is on the radar of everybody from homeowners to multinational corporations and will become more attractive and affordable as time goes on.