There is such a wide range of light bulbs available on the market that it is sometimes difficult to make a choice. It is possible to take into account quantitative elements (energy efficiency, life-time of the bulb) as well as qualitative aspects (quality of light, colour rendition, recycling, etc.). Here is an overview of the different kinds of light bulbs and their energy efficiency patterns.

To reduce your electricity bill, forget filament lamps…

If electricity is used to heat your home and water, doing so represents 80% of your overall electricity consumption. In that case, lighting accounts for an estimated 3%. But if you take heating and hot water out of the equation and focus on home appliances, then lamps and light bulbs use up 14% of the total, less than a fridge and a freezer combined (32%) but as much as the dishwasher (14%),  the dryer (14%) and more than an audiovisual equipment (12%). Home lighting thus represents a significant part of a household’s electricity consumption, which justifies the use of more and more energy efficient light bulbs.

Electrical lighting is based on two separate technologies: filament lamps (aka incandescent bulbs) and fluorescent lamps. In the former, a tungsten filament wire is heated until it glows. It is the oldest method and is still widely used today. However it wastes a lot of energy since filament lamps only convert 5 to 8% of the power they use into visible light; the rest gets lost via heat and infrared light. Besides, their life span is limited: barely 1000 hours for a conventional filament bulb.

Halogen bulbs are an improvement from conventional filament lamps. Their higher temperature yields more power; furthermore, they provide an excellent colour rendition and contrary to common beliefs, they have a higher light efficiency than standard incandescent bulbs because they emit a wider segment of the visible light spectrum. Nevertheless, they use up a lot of energy and have a limited life span, barely twice as high as standard filament bulbs, that is about 2000 h.

… and move on to fluorescent bulbs

The marketing of “low-energy light bulbs” coined new terms such as “compact fluorescent lights” (CFL), “discharge lamps” or “energy-saving light bulbs”. They actually all mean the same thing, that is fluorescent lamps. Such lamps have no filament but two electrodes, between which a discharge generates an electric arc in a bulb filled with noble gases, metal fumes (sodium or mercury) and rare earths. Historically, the first examples of this technology are neon tubes, which have been used for illuminated signs since the middle of the last century. Actually, a CFL is nothing more than a fluorescent tube folded on itself so it takes less space.

Compact fluorescent lights offer unquestionable advantages compared to filament lamps: their average life span is ten times longer and they offer higher light efficiency, from 60 to 100 lumens per watt (lm/W) compared to 12 to 20 lm/W for standard bulbs. Finally, they produce much less heat.

How to achieve efficient and economical home lighting

Not all kinds of light bulbs fit all places in your home. For instance, although they are bound to disappear because they use up to much power, filament lamps are ideal for spot-lighting, in the corridor or in the toilets for example. It is easy to compensate their low energy efficiency by combining them to a time-switch or a motion sensor and by using them briefly, only when necessary. Fluorescent lights, on the contrary, are suited for rooms where long-lasting lighting is required, which makes their slight ignition delay less of a problem. However, they have the important disadvantage of containing toxic substances and must be recycled, especially to avoid mercury pollution.

But as far as energy efficiency is concerned, light-emitting diodes or LEDs are undoubtedly the most promising technology. Unfortunately, so far, their colour rendition (measured by the colour rendering index, CRI) is really unsatisfactory: their monochromatic light (be it blue, green or red LEDs) is not adequate for home lighting and research on white LEDs has not advanced enough yet. For the time being, they may only be used at home for ambiance lighting and decoration.

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The emergence of digital technology opens yet unexplored paths towards enhanced quality of life. Here is an overview of some innovations which could soon make their way to our homes, allowing for increased comfort as well as energy savings.

On-demand heating

The share of income spent by households on heating has been relatively steady since 2006 (study on household energy bills) in spite of the successive sets of regulations imposing improved building insulation. One of the reasons for that is the so-called “house effect” stressed in a study conducted by the French General Sustainable Development Commissioner: as the inhabited surface area tends to grow, new means must be found to cut heating demand in order to reduce energy consumption.

Digital technology and its applications in home automation schemes offer promising perspectives to reach that goal. Specific software enables, among other things, the implementation of tools aimed at optimizing the consumption of the different energy fluxes within a building. So-called “eco-detection”, for instance, interrupts heating and air-conditioning systems as soon as the building is excessively exposed to outside weather changes. The “eco-indicator” provides information on how much spending any heating demand requires, which users take into account in order to adjust their consumption. Finally, the “eco-citizen” aggregates different data to suggest adjustment in temperature according to the recommendations of the ADEME, the French Environment and Energy Management Agency.

Adjusted lighting

In 2007, the ADEME said that about 15% of our energy bills was due to lighting (apart from heating and domestic water). Digital tools bring about innovating solutions, such as an automatic shutdown system, a timer and motion sensor / presence detector. Underlying these reflexions is the willingness to adjust consumption without the need for direct human intervention. Another concrete example of this: lighting power in the house could be automatically adjusted according to the intensity of outside, natural light. By signing an agreement in September 2012 pushed forward by the Syndicat de l’éclairage (French lighting industry federation) within the framework of the Grenelle Environnement (a multi-party debate in France on environmental issues), all players in the industry expressed their shared concern over environmental issues and their common willingness to promote and offer affordable equipment.

Optimized home automation interface

Finally, all of these new features can now be managed from a single interface. But not just the centralization of commands makes home automation “2.0” interesting: these parameters can now be remotely modified at any time, thanks to smartphone or tablet applications. With such equipment becoming mainstream and the public growing increasingly accustomed to touch-screen interfaces, remote control via a wide range of ergonomic options has become trouble-free. This innovation will undoubtedly have the greatest impact on the success of home automation equipment, considering that smartphones now outsell personal computers (Canalys study). Preheating your oven a few minutes before getting home is no longer science fiction.

Photo : nuage_de_lait

For more information:

• How can home automation increase a building’s energy efficiency
• What kind of light bulbs should you use? Focus on home lighting
• What’s the most energy-consuming household appliance?

“LEDs could represent 75% of the lighting market by 2020” according to Christophe Bresson, commercial director of the lighting department at Philips. Such an assumption may sound surprising, given the dominating position of traditional filament lamps and compact fluorescent bulbs on the lighting market, but it is based on the huge electricity efficiency potential of LEDs. Although there is still a great deal of progress to be made, especially with regards to colour rendition, impressive improvements such as flexible and organic LEDs are coming to light. Here is a short overview of a promising, fledgling technology.

How is light efficiency measured?

The electricity or light efficiency of a lighting device is expressed in lumens per watt, a measurement unit expressing the relationship between the light it emits and the power it uses. Traditional incandescent bulbs have a light efficiency of 12 to 20 lm/W, compared with 60 to 100 for compact fluorescent, aka low-energy light bulbs. The light efficiency of LEDs is likely to become twice higher as it is now and reach 150 lm/W, which would make them the undisputed champions of light efficiency!

Technical obstacles and innovations: LEDs, OLEDs and FOLEDs

A LED is an optoelectronic device emitting light (photons) when electric current (electrons) travels through it. Both very efficient and long-lasting, with a lifetime of about 50,000 hours, LEDs, though, suffer from defects which prevent them from winning further market shares. They remain expensive, mainly because of the rare earths they contain, 97% of which are produced in China which controls prices. Besides, their colour rendering index (CRI) is still unsatisfactory.

Organic LEDS or OLEDs are seen as a major innovation. They contain layers of organic semiconductors, that is made from carbon (crystals and polymers, as opposed to inorganic semiconductors such as silicon), located between two electrodes, one of which at least transparent. OLEDs have the dual benefit of being made of cheaper materials and generating light on thin and extensive layers. When built on a flexible plastic substrate, they become soft: FOLEDs (for Flexible Organic Light-Emitting Diodes) open up a host of unsuspected possibilities for tomorrow’s electronics (soft and foldable screens, lighting wallpaper, etc.)

However, two hurdles remain: the light yield of OLEDs is far below this of traditional LEDs so far, and their lifetime is relatively limited (14,000 hours).

Such drawbacks make some experts assume that by 2020 OLEDs will only find use in niche applications on the broader lighting market, such as defence equipment for instance. Although they are still too expensive to conquer the mainstream market, OLEDs represent a dramatic improvement in modern lighting.

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Given that data centers are becoming larger and more numerous, the theme of making them more energy efficient is coming increasingly to the fore. The scale of the data center power usage is now making it a concern, not just of those in the IT industry, but also of energy policymakers at large.

According to the Climate Group’s SMART 2020 report, data centers represented 14 percent of the global IT footprint, which in turn represented 2 percent of total worldwide carbon emissions. Furthermore, data center emissions look set to increase for the foreseeable future. A research paper produced by Rice University and the Singapore Institute for Sustainable and Applied Infodynamics claimed data center-related emissions would triple by 2020.

Lighting up efficiency

However, besides increasing the efficiency of the server units themselves, or switching them to standby mode during downtime, how can energy and cost savings be made in data centers?

The answer, it seems, could be focusing on the lighting.

According to an editorial in the Data Center Journal, while lighting only accounts for between 3 and 5 percent of data centers’ electrical load, it can make a big difference to their power usage effectiveness (PUE), the measure of a data center’s energy efficiency. In the article, it is stated that energy efficient lighting networks that integrate building performance systems can improve PUE by as much as 25 percent.

Sam Klepper of Redwood Systems, who wrote the piece, said intelligent lighting systems and light-emitting diodes (LEDs) were key to energy efficiency improvements in data centers:

“It’s not the average light bulb that can streamline the operations of sprawling data centers, however. Only an intelligent lighting system can (and does) do the job. To understand how a building-performance lighting platform can serve as the catalyst to creating significantly more-efficient data centers, it’s important to look at the heart of the lighting system: networked light-emitting diodes.”

Klepper went on to describe how data centers could customize their lighting systems in order to adapt to their lighting needs. Klepper said this customization might include:

• Sensor-driven, occupancy-based lighting to ensure lights only switch on when employees need them;
• daylight harvesting, which automatically adjusts to light levels;
• lighting policy scheduling that accommodates lighting needs at different times of day;
• automatic fixture outage alerts for facilities managers; and
• fixture-specific data collection, enabling the analysis of each light’s use to inform any necessary fine-tuning and to minimize wasted energy and money.

Carbon neutral data hosting

Lighting aside, data centers do seem to be becoming more energy efficient. Just over a year ago, British IT hosting company UKFast claimed to be the world’s first carbon neutral hosting company. In addition to offsetting all its CO2 emissions, the Manchester-based firm also has plans to generate its own clean energy from hydroelectric power plants.

Read more:

• Bright ideas for street lighting.
• Energy efficiency, considering the consumption issues of tomorrow.

• Issue

The European Commission adopted on 15 December 2011 a Green Paper « Lighting the Future: Accelerating the Deployment of Innovative Lighting Technologies ». This Green Paper intends to launch a broad debate with stakeholders to accelerate the large-scale deployment of SSL technology (Solid State Lighting). A public consultation has been opened in parallel and aims at collecting the contributions of all interested parties.

• Challenges

→ Identifying obstacles to the large-scale deployment of innovative lighting technologies

The Green Paper is designed to open a large public debate on obstacles to the wide-scale uptake of innovative lighting solutions of high-quality in the EU. It covers SSL technology in the broad sense and comprises both Light Emitting Diodes (LED) and Organic LED (OLED).

→ Defining  a coherent set of strategic objectives

The Green Paper is designed to help the EU achieve the energy efficiency, industrial development and innovation objectives set in the frame of the Europe 2020 strategy. It pursues two key objectives: raising awareness among European users, professional or public, about the quality of SSL technologies and their energy efficiency potential; proposing policies which foster the competitiveness and global leadership of the lighting industry.

→ Seeking the views of all interested parties of the sector

A public consultation is open until 29 February 2012 which addresses both the demand and supply sides of innovative lighting technologies; it targets both European users, professional or private, and the European lighting industry. Individual consumers and professional users, the lighting industry, the building and construction sector, architects, lighting designers, electrical installer, municipalities, public authorities, civil society communities, professional associations and all other relevant stakeholders involved or interested in the topic are invited to participate. Member States and the European Parliament are also invited to take part to the debate.

→ Exploring new measures

The Green Paper raises the question of the need for new instruments, both voluntary and mandatory, at EU level, to allow a wider market uptake for SSL technologies. It highlights a series of actions the European Commission is considering to overcome current obstacles to a large-scale penetration of innovative lighting technologies.

• The initiatives considered

The Green Paper highlights a series of initiatives that could be launched at EU level to promote the large-scale deployment of SSL products:

→ Concerning consumers and users, the objectives are to:

-Better inform consumers on SSL products and ensure that the latter conform to EU legislation on minimum  product performance and safety requirements;

-Create SSL lead markets for cities for SSL products by mobilizing the ELENA technical assistance facility or the European Energy Efficiency Fund (EEEF) and organising awareness-raising campaigns to cities;

-Create SSL lead markets for SSL products in public and residential buildings by fully implementing political and legislative instruments and providing incentives.

→ Concerning the European lighting industry, the objectives are to:

-Secure the supply of scarce raw materials and improve recycling of end-of-life products;

- Improve access to intellectual property rights and SSL products standardisation, including on safety issues, environmental aspects and procedures and common methodologies for measuring the performance of SSL products and systems;

- Strengthen R&D in photonics in general and in SSL in particular, and improve the market uptake of R&D results;

-Improve learning and training through vocational and lifelong learning and training of the actors of the sector;

-Strengthen the SSL value chain (from raw materials to manufacturing and final products, including component and equipment suppliers) to overcome existing fragmentation in the lighting industry and to create cooperation platforms along the value chain;

-Strengthen the links between the industry and consumers to encourage a fast uptake of products;

-Develop a European approach to SSL bringing together the European Commission and industry representatives.

• Next steps

The results of the public consultation will be summarised in a report which will feed into the reflection of the European Commission on the necessity to take new regulatory or non-regulatory measures to accelerate the deployment of innovative lighting technologies throughout the EU. Proposals could be made in the next months.

• Useful Links

Website of Directorate-General for the Information Society (European Commission)

http://ec.europa.eu/information_society/digital-agenda/actions/ssl-consultation/index_en.htm

You will find all the International Review about Regulations in Electrical Efficiency on the web site:

http://www.electrical-efficiency.com/category/regulation/rexel-international-review/

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