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Choose LEDs – save the world

issue 36 Apr / May 2007

This month Geoff has decided to focus our attention on one of the main drivers for the adoption of LED lighting fixtures – sustainable and environmental development.

Throughout previous articles I have endeavoured to highlight some of the main drivers and challenges facing the solid-state lighting industry as it begins to displace conventional 20th Century light sources (see figure 1). However, at this point in history it is the environmentally friendly or sustainability factors that are beginning to accelerate the need and desire for LED lighting.
Stop! I here you cry, I remember the good old 1980’s with the Rubik’s cube, the Power Transformers and when environmentalism was the height of fashion. There were a plethora of new products in all sorts of consumer market sectors proudly announcing their green credentials but unfortunately they didn’t stand the test of time and consumers quickly lost interest.
However, fast forward to the end of October 2006 and you will observe a changing point in history that has the potential to radically change the lighting industry forever and provide a significant platform for a boost in LEDs and Solid-State Lighting. This was when the hard hitting Stern Review on the economics of climate change was published, dominating the world’s headlines and most notably changing the mindsets of the most powerful executives within the world’s largest organisations. The Stern report warns that climate change and global warming will have catastrophic consequences for the global economy unless effective international action in reducing carbon emissions is taken now by governments, businesses and individuals.
A cynic might ask whether this is another fleeting environmental fashion moment. However the consensus view is that this time it is something far more fundamental. Today, there is little doubt that consumers are once again interested in green and environmentally friendly products along with the obvious advantages they bring such as energy cost savings however there are two fundamental changes from the last 1980’s green consumer boom cycle:

1. A high level of political awareness:
There is a much higher level of political awareness at all levels about the need to change and the need to change quickly.
2. A high level of corporate interest:
The biggest impact is that corporate organisations are taking high levels of interest in environmental issues in all sectors from banking, retail through to aviation and manufacturing. Large corporate organisations understand that climate change is a very big challenge and will require all their innovation and creativity to deliver a solution.
In a similar call to arms as the famous First World War poster depicting Lord Kitchener, it is clear that the world needs everyone to do their bit and save energy but how does this really impact both the consumer and business users?
Well to start, lighting is present in every household and business premises, it represents a considerable share of the electricity consumption in both residential and many commercial lighting applications. Although we are well aware that lighting is an important part of our electricity consumption there are still many of us that are reluctant to install energy efficient lighting technologies. Therefore there are significant savings of energy consumption and money still to be made enabling solid-state lighting manufacturers to seize a significant market opportunity in residential applications. There are also significant opportunities in certain commercial lighting applications such as the retail sector where approximately 30% of all electricity is consumed by lighting applications.

UK Lighting Energy consumption
Let us start by assessing whether there is the fundamental need to save energy within the lighting sectors and in order to do this we need to have some actual data about electricity consumption used in residential and commercial lighting markets. Although it is not easy to compile accurate and comprehensive data on the total end-use consumption of lighting there are a few robust UK metrics that serve the purpose of this article.

Residential Lighting

There were approximately 25.6 million households in the UK in 2005 and the residential electricity consumption was nearly 112 TWh (Terra Watt Hours) or more appropriately 112,000,000,000,000 Watt Hours. It has been estimated by the European Commission – DG Joint research Centre that 17.9TWh is used for lighting consumption within the UK residential market making lighting represent approximately 16% of the total domestic electricity consumed. This residential lighting energy consumption is the CO2 equivalent of driving an average car more than 21,927,500,000 miles!
Both the number of households and the number of lighting fittings within each household is projected to rise in the future due to government policies to create affordable housing and the consumer trend for multiple light sources within a room. This will lead to an increase in electricity usage unless more energy efficient lamps are adopted within the home.
The percentage of UK households that contain at least one, energy efficient light source is estimated to be approximately 50% and the light source is usually a compact fluorescent lamp (CFL) type. On average there are approximately two CFL’s per household (including households without CFL’s) out of an average of 22 lamps per household. Therefore, the penetration of energy efficient light sources within the UK home is about 9% providing a significant potential for energy savings. For example, if an additional 3 LED-based light bulbs were to be placed in every home in the UK it would generate a market for more than 68.4 million LED-based light bulb replacements!
Figure 2 outlines the carbon footprint that lighting and appliances make within the home as a percentage of the total household CO2 emissions, representing nearly a quarter of all emissions.
Although the total household emissions for lighting and appliances represents just 22% of the total CO2 emissions it is still the second most polluting aspect of our homes after heating.
Figure 3 shows the percentage of electricity usage for lighting as a percentage of all household appliances. Although the trend demonstrates that lighting has gradually reduced from 21.4% to approximately 20.2% between 1990 and 2004 the overall energy consumption for lighting has increased as indicated by Figure 4. One possible explanation is that electrical consumption of other appliances has increased due to more household personal devices requiring power such as multiple household TV’s, iPODs, computers, PC’s and games consoles.
Sadly, it is evident that the reduction of lighting electricity consumption as a percentage of household usage, shown in Figure 3, is not due to the use of energy efficient lighting as the total amount of energy consumed in lighting has increased but not as fast as other electricity consuming devices.
The main reason for the lack of adoption of energy efficient lighting in homes is mainly due to consumer choice, they prefer lighting that provides a lively feel to a room. This is the main issue that CFL technology has failed to deliver over the last decade as they include poor quality light output combined with an unwanted delay in obtaining an immediate 100% brightness after switching on. Despite heavy government subsidies CFL technology has achieved little market penetration in the home as the consumers have preferred the light quality of other more inefficient light sources. This provides a huge market opportunity for the UK government to support LED technology within an emerging UK SSL industry which addresses the main consumer barriers whilst helping to reduce our national carbon footprint.
In figure 4, the increasing energy requirements for domestic lighting is clearly shown with more than 19.4 million tonnes of oil equivalents required to light UK homes. It is predicted by the Market Transformation Programme operated by DEFRA that UK domestic lighting demands will reach nearly 20 TWh by 2020, an increase of 3TWh, unless drastic market penetration of energy efficient lighting occurs.
Today, the average UK household consumes approximately 700 KWh for lighting representing the equivalent of 309 kilogram’s of CO2 emissions each year. To put this in context your lighting would produce the equivalent CO2 output as a BMW 318i petrol car driven more than 1700 kilometres!
The UK Solid-State Lighting industry can play a significant role in supporting the UK reach its green house gas emission targets and help reduce the annual electricity usage by approximately 2,197GWh simply by achieving the following:

  • Ensure that each household installs 3 LED-based lighting products. This would still only mean 25% market penetration of energy efficient light sources within UK households.
  • Develop LED-based light sources that meet consumers requirements of “bright and alive” rather than “dull and dead” light sources.
  • Develop responsive light sources that provide immediate-on lighting and which can be easily controlled and dimmed.
  • Develop LED-based light sources that met a minimum of 60-70 lumen per watt wall-plug efficacy

The energy savings of 2,197GWh is the equivalent of playing more than 8.3 million Playstation 2 games consoles for a complete year or driving more than trillion miles!
If these targets were achieved then it is believed that consumers would certainly choose LED technologies given the current consumer environment for green technologies. In fact many governments such as the US, Australia and Europe are proposing to ban or at least phase out incandescent bulbs over the next few years providing a significant driver of adoption for SSL technologies.
If the UK SSL industry and government were to work together to develop energy efficient light sources and government policies speeding their adoption it would be possible to replace 60W incandescent lamps with 100 lm/W LED-based light sources for our homes within the next 5 years. Such technology could help reduce the 18TWh of electricity used in residential lighting today by up to 80%, the equivalent of mitigating the need of 2.5 new nuclear power stations the size of Dungeness B!

Commercial Lighting
The commercial lighting sector also provides a significant opportunity for the UK SSL lighting industry to assist the government in reducing it CO2 emissions. The amount of lighting used within offices, retail, hotels, public service building, industrial warehouse facilities and street lighting is significant. Indeed, commercial lighting accounts for approximately 22% of non-domestic electricity use and is expected to be approximately 44.8TWh by 2010.
The opportunity for deploying LEDs within commercial lighting applications are again significant especially as high powered white LEDs have recently become available (see December/January mondo*arc edition for a round-up of the latest LED technologies). The current Part L2 of the building regulations was revised in April 2006 and aims for between 23.5% and 28% reduction over the whole building in energy consumption compared with a similar building built to 2002 standards. Part L2 sets an efficiency level of 50 lamp lumens per circuit–watt for general lighting – this measure includes the efficiency of the lamp and its associated control gear such as the ballast. For display lighting the efficiency should be greater than 15 lamp lumens per circuit–watt. Until last year the Part L2 lumen per watt figures where extremely difficult for white LED light to achieve. However today’s high power white LEDs are achieving between 60 to 100 lumens per watt.
Unfortunately, the Part L2 building regulations discuss lamp and driver efficiency rather than the power and efficiency required to deliver useable light where it is needed in an application. As LEDs are a naturally directional light source they become significantly more efficient than conventional light sources that require complex reflector or fixture designs to control and guide the light. For example, in many practical lighting fixture examples such as a CFL down lighter the useable light output can be reduced by more than 60% due to lost or unusable light from the lighting fixture design. Practically, this could mean that even if the CFL had an efficiency of 60 lumens per watt (and pass the Part L2 requirements) it would only have a useable light efficiency of 24 lumens per watt which would not pass the Part L2 efficiency requirements as intended. On the other hand most LED fixtures can utilise between 70-80% of the light emitted from an LED and therefore a 30W LED fixture could provide the same light as a CFL based fixture providing a 50% energy saving!
Many LED manufacturers are now proposing that lighting fixtures and lighting regulations should stress the useable light efficiency as the metric for lighting requirements as it provides an improved estimate of total lighting efficiency. This would obviously provide LED-based lighting fixtures with an advantage moving forward and future pressure should be exerted to increase the Part L2 building regulations minimum lighting efficiencies to 70 or 80 lumens per watt to provide a significant incentive for conventional lighting companies to adopt LED lighting and reduce the UK’s carbon footprint.
A recent MTP report suggested that more than 5 TWh of electricity usage could be saved by 2020 by incorporating LEDs within commercial lighting applications however this figure could be conservative considering the rapid appreciation in LED efficiency and depreciation in LED costs (more than 30% per year).

Figure 5 demonstrates the retail and transport sectors use more than 25% of their annual electrical energy consumption on lighting applications and therefore are key markets within the service sector to benefit most from adopting LED-based fixtures.In retail the advantages of energy efficient lighting are clear and in 2005 Tesco invested over £4 million in energy efficient lighting, infra-red lighting sensors and dimming lighting with the result of saving over 40 million KWh and over 17,000 tonnes of CO2 a year.

Street Lighting and Traffic Signals
The illuminated equipment market incorporates street lighting, illuminated signs, traffic signals, pelican crossings and illuminated bollards. There are over seven million items of illuminated equipment throughout the United Kingdom (see table 1) and this sector is estimated to be valued at £450 million per year. Almost 40% of this sum is spent on energy and service charges to the electricity supplier. Of the balance, 70% is spent on maintaining the infrastructure and the remainder on new projects.
Street lighting accounts for about 1% of all non-domestic electricity use (~ 2.7TWh) and the energy used is expected to increase by 0.7 TWh by 2020, mainly as a result of new roads in housing estates. This equates to more than 6 billion Kgs of CO2 emissions per year.
Recently, street lighting has become a rather significant issue as many types of councils responsible for street lighting have seen significant rises in energy costs putting considerable strain on their budgets. For example, Devon has more than 70,000 street lights and 12,000 illuminated traffic signs which accounts for nearly 40% of its carbon dioxide emissions. The street lighting and signage costs more than £2.5 million in electricity charges per year (see Unfortunately, many local authorities are attempting to reduce energy costs by switching off or operating street lighting for shorter periods of time. However this has serious consequences for personal safety and street crime.
LED street lighting systems offer the street lighting engineer and local authority a new opportunity to deliver quality lighting with intelligence and reducing energy consumption. The British Standard recommends that all new street lighting should be provided by lamps that have a colour rendering index greater than 20, ie; low pressure sodium lamps which do not have any colour rendering properties are no longer recommended. The use of “white light” sources with a CRI greater than 60 allows a lower lighting class to be used on residential roads bringing potential savings in energy consumption, reductions in light pollution and increased amenity due to the improved colour rendering of light. LEDs appear to offer the future solution for street lighting applications with instant on and re-strike times, the ability to dim efficiently, high colour rendition and high efficacy.
The UK has an estimated 420,000 traffic and pedestrian signal heads which currently use between 18 and 21 MW of electricity per year. If all of the traffic signals in the UK were to be converted to LED lights the amount of energy saved would be equivalent to approximately 102 MWh and reduce CO2 emissions by approximately 50,000 tonnes.

Recent SSL technology advances
The recent advances in materials, packaging and optical design for LED fixtures are making commercial, residential and street lighting applications ever more achievable within the short term. For example, CREE incorporated has recently announced a high-end XR-E warm white LED product with a typical luminous flux of 70 lumens at 350mA and 120 lumens at 700mA with a CCT of 3700K. This warm white LED is ideally suited for applications within the retail and residential markets as they provide high colour rendering with warm and lively outputs.
Other leading LED manufacturers are also developing high powered LEDs for commercial lighting applications with Philips Lumileds recently announcing a pre-production research LED device that delivers 136 lumens when driven with a current of 350mA, corresponding to an efficacy of 115 lm/W. Philips Lumileds emphasises the correlated colour temperature (CCT) is 4685K and impressively, the white LED can be driven at 2000mA to deliver 502 lumens, corresponding to an efficacy of 61 lm/W.

It is clear that LED technology is rapidly advancing and offers a significant opportunity for the consumer, business and governments to reduce their carbon footprint whilst improving the quality of light within their home and office environments.
History will show that 2007 became the year when SSL competed on an even playing field and began to displace conventional light sources within the residential and commercial lighting markets.
The strength of consumer choice demanding high quality and responsive lighting will be enough for LEDs to outperform any challenge from CFL’s and the environmental angle will tempt consumers to choose LEDs despite the initial cost implications. Indeed, if the additional functionality LEDs can offer to general lighting were to be adopted into new LED-based lighting fixtures it would provide a strong reason for consumers to pay more for a brand or icon they want. This would be the equivalent of the iPOD effect whereby consumers are willing to pay more for an iPOD over other music playing devices because of the increased brand awareness and perceived improved functionality. The same can happen for LED-based lighting except that consumers could pay more for REAL increases in lighting performance and functionality.
Although we have witnessed the birth of many new SSL companies over the last few years there is still a tremendous market opportunity for companies to create new LED-based products and generate significant wealth for their shareholders and the country they reside in. The SSL market is estimated to be worth in excess of $150 billion by 2020 and was approximately $1 billion in 2006 indicating there is going to be considerable demand for SSL products during the next decade.
Today, we are approaching the time where generally, city investors are starting to become interested in SSL technologies due to the huge market potential creating the possibility for a new bread of lighting companies within the UK.
This will undoubtedly be an unprecedented time of growth for the SSL market, one of which we may never be see again in our lifetime. Therefore if you are thinking about creating a lighting company there could be no better time than now!
The next article will discuss Organic LEDs (OLEDs) as a potential SSL technology beyond 2015 however if you would like to know more about this or any LED lighting topic then please email me at



Figure 1: Main drivers and challenges facing the LED and SSL industry


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    Figure 2: Residential Carbon Dioxide Emissions in 2003, source DTI
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    Figure 3: The total electricity consumption of lighting as a percentage of domestic appliances in the UK
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    Figure 4: Domestic Energy Consumption of Lighting since 1990
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    Figure 5: Lighting as a percentage of energy consumption within the service sector
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