Solid state lighting (SSL) is a relatively new technology for the lighting industry. Among this technology are Light Emitting Diodes (LEDs), which are becoming increasingly available for a variety of applications such as displays, signs, traffic lights, car head lamps and brake lights, and city beautification. The technology is still in development phase to increase light output while reducing costs, and to provide an efficient warm white light.
Even more exciting is the fact that LEDs allow us to create lighting solutions in places and in ways, which were never possible before. And they are also a good environmental choice with the potential to significantly reduce energy consumption and indirectly CO2 emissions.
So how will LEDs develop and grow the existing general lighting markets? Assuming that LED lighting continues to develop as predicted, here is a rough guide to the future.
For some time now LED lighting systems have been used to light up buildings, bridges and monuments in our cities. Due to their flexibility and the possibility to set any desired colour, LEDs offer lighting solutions which are simply not possible with any other existing technologies, for example, creating effects such as colour wall washing, creating sharp light/shadow lines. LEDs are also ideal to avoid or minimise light pollution since the light can be precisely targeted and integrated on the walls. Further benefits include lower maintenance costs, low energy consumption and a general enhancement of the architecture of the building or structure. This shift to LEDs will continue in the future.
Offices are already seeing the first niche LED applications with desk lights and particularly emergency lighting. However, as replacements for conventional general lighting (for example, excellent TL5, TL-D, MASTER PL fluorescents with luminaires optimised for them), LEDs are still some years off because the cost / lumen ratio is still too high – performance will have to improve (at least >80 lm/w at a system level) to be able to compete with existing technologies.
Opportunities for LEDs to add new lighting in offices are significant. We will see LEDs being integrated into ceilings, wall panels and floor tiles lighting up hallways. Within the next few years we should also see the first effective LED solutions in specialised areas of the office, for example in reception areas, restaurants and guest areas where more decorative effects are required. These will be typically high end and prestige type projects. Within three to five years the first solutions will become available which can compete with compact fluorescent technology on total cost of ownership. Within five to ten years LEDs will become a viable alternative for general lighting solutions; it will be some years more before LEDs will be the clear choice.
LED replacements / retrofits are already making a small impact in industrial niche areas mainly concerned with lighting in fire hazard and explosion-risk areas (equipment complying with the ATEX Directive). LEDs are ideal because they operate at Safety Extra Low Voltages (SELV) – typically 12 or 24V. Their reliability and long life is also a clear advantage, as downtime can be highly expensive and possibly dangerous. LEDs’ instant flicker-free turn-on is important for emergency and security lighting. But for new general lighting LED systems in industrial lighting such as in manufacturing plants, oil & gas production, plus refineries, expect eight to ten years.
LED clusters have been used as incandescent lamp replacements in traffic signals and pedestrian lights for some years, particularly in the USA (around 30% in 2002) and in Europe. A lot of energy is saved, especially as red LEDs need no filters (colour filtered incandescent lamps can lose 90% of available light). LEDs’ high reliability is crucial; replacing lamps is expensive and failed signals dangerous. Expect all traffic lights to be converted to LEDs within five to ten years. Decorative LED lighting is already becoming available in markets for pedestrian and residential areas next to roads and LEDs clearly have the potential to change the way we light our streets and roads at night, for example by being embedded into new pavements or safety fences etc.
However general road lighting probably presents LEDs with their biggest challenge, as they will have to compete with a new generation of existing compact HID lamps which offer tremendous potential. Costs need to be reduced and white light performance improved before LEDs start to be more widely used. LEDs do have the potential in time to offer new ways of lighting our roads but expect five to ten years+ for new types of mainstream LED road lighting.
Hotels are installing LED lighting for decorative purposes (colours, dynamic lighting) in reception areas and lobby’s. Furthermore hotels are already installing LEDs in bedside and standing lamps. Also, effective are LED downlighters which are expected within a year or so. Hotel lighting costs are high and a change to LEDs makes economic sense. LED energy saving is important for another reason – it is increasingly important for hotel operators to emphasise their sustainability credentials. One challenge remaining for LEDs is to produce an efficient warm white light.
Based on initial costs and performance, a clear choice to replace existing halogen and fluorescent lighting in general lighting areas will take a few years although in some areas this process has already started.
LED lighting is growing fast in this sector where decorative effects are key. For example, in signage lighting LEDs offer major benefits over traditional Neon lamps (they are smaller and more robust, last longer, need less maintenance, save energy and are safer). Furthermore the dynamic use of colour and new effects offers owners opportunities to differentiate themselves and create welcoming environments for customers. Expect this trend to continue to develop rapidly.
Thanks to the advent of LEDs, coloured light is much easier to use nowadays, and coloured lighting solutions – fluorescent or LED – are becoming increasingly popular in healthcare facilities. New, more sophisticated lighting control systems have made it easier to use dynamic coloured lighting. If designed well, coloured light can be used very effectively in making hospitals feeling less like hospitals by influencing wellbeing, emotion and mood. For example, in with the LED-based concept AmbiScene for scan rooms, coloured light by the LED-Wall washer could be used to communicate signals between patient and staff, underline a specific theme for the patient and could create an emotional state of mind for the patient.
In the coming years we expect to enlarge the application areas of LED’s of scan rooms in hospitals to other application areas of the hospital as well as other segments within the healthcare industry.
Commercial freezers are already being fitted with LEDs as replacements for TL fluorescent lamps. This will increase. Freezer cabinets make an excellent application for LEDs on a total cost of ownership basis too. The reason is that conventionally used TL lamps at -20oC run sub-optimally, giving shorter lives and poor efficacies. Unaffected by cold, LEDs are more energy efficient and will outlast the freezer cabinet. They are also less easily damaged. Regarding LEDs providing a similar performance to existing lighting in new installations, expect new LED shelf lighting within a year (good for food as LEDs don’t heat the produce), and effective LED mini spotlights soon after. These lighting systems should be as unobtrusive as possible and compact LEDs are ideal and will grow the areas and applications for lighting.
Within three to five years, LEDs should start to find general lighting applications in retail spaces. LED energy saving is also a sustainability driver in this sector. In terms of a clear choice for LEDs for general lighting, this will probably take five to ten years.
The potential for LEDs to grow the number of lighting applications in the retail fashion segment is very significant and they are already being used for ambience creation and dynamic effects. Examples of this potential include shelf lighting – where traditional fluorescent lamps are too large to be used and for colour wall washing between merchandise.
In general lighting LEDs will have to compete with today’s preferred solution for general lighting – the very advanced Compact HID systems with their excellent performance and high lumen packages. This means it will probably be at least five to ten years before effective LED lighting solutions will start to appear in mainstream shop lighting.
LEDs represent the most significant development in lighting since the invention of the electric light more than a century ago and we should expect the current rapid pace of change to continue.
In order to truly appreciate this impact lets take the analogy of the development of the transistor. The question is not which transistors replaced what vacuum radio-tubes by when, but that transistors created mobile phones, walkmans, PC’s etc.
The same is true for new LED lighting systems. The main question is not when they will replace what by when, but what new developments will be made possible.