LIGHTING UP YOUR HOMES!!! CHEAPEST OPTIONS!!!

Lighting up Your Home – the cheapest options By Harsha Wickramasinghe

Apart from lighting, electricity is also said to be a powerful tool in fighting poverty. Surveys make it evident that higher rates of electrification are nearly always accompanied by lower incidences of poverty. Phrased differently, better electrification indicates low poverty.

Four in every five households in Sri Lanka, at present, are enjoying the benefits of grid electricity, while another one in every fifty meets their needs through the off-grid. Collectively therefore, more than 82 % of the country’s population benefits from electricity, which makes us exceptional within the South Asian region, for the average rate of electrification of most other counterparts falls below 40 %.

During the early days of electrification the preferred choice of power generation were engine driven generators. These were later replaced by hydropower generators following the pioneering work of Eng. Wimalasurendra. By virtue of being the cheapest mode of power generation, hydropower dominated the electricity supply in Sri Lanka until the last decade, meeting nearly the total requirement of electricity. In this bygone, yet ‘golden’ era, the preferred choice for lighting up homes was the incandescent filament lamp (IFL), the common bulb, even though today, it is designated as one of the most inefficient lighting devices in the market. However, with the increasing demand for electricity in lighting and other uses, the dominance of hydropower steadily waned off, paving the way for expensive, yet easy and quick thermal power generation.

Electricity generation at present is dominated by thermal power (65 %) followed by hydropower (32 %) and non-conventional renewable energy (3 %). However, our power system is greatly burdened during the peak demand period, i.e., from 6.30 pm to 9.30 pm, mainly due to the use of IFLs for lighting homes. Even though the domestic consumer pays around Rs. 5 – 15 /= for a unit of electricity, the actual cost of meeting this peak demand is several times higher.


Incandescent Filament Lamps (IFL)

IFLs are said to have a luminous efficacy below 25 lumens per Watt of electricity spent. Lumen is a measurement of the light output. 25 lumens is a relatively low value, which also makes IFLs the root cause of many problems in operating power systems the world over. Many countries, including Sri Lanka are therefore planning to phase out this lamp in the near future. Australia has already phased out IFLs. Following suite, the European Union envisages phasing them out within the next few years.


However, this low efficient lamp is still preferred by most local consumers as it is cheap and widely available. Architects too prefer this lamp, due to its warm and easily controllable nature. They are therefore very much popular in décor.

Although Sri Lanka is endowed with a high rate of electrification, strangely enough, this very rate has now doubled up as a serious issue, for this exponential expansion in the national grid has outpaced the country’s economic growth rate. Hence increasing public awareness on the possibilities of using better and efficient lighting devices is of utmost importance.


Linear Fluorescent Lamps (LFL)

The most common lighting device after IFLs is the linear fluorescent lamps (LFL) or tube lights as commonly known. LFLs are a very high efficient lighting device where the luminous efficacy is around 70 lumens per Watt of electricity spent. However, a major drawback of LFLs is the poor aesthetic appeal which limits its use to commercial and non-living areas of homes such as garages and kitchens. Many consumers are known to disdain LFLs owing to its bright white light and the long not-so-attractive cylindrical shape. It is perhaps an eyesore in your living room.

LFLs are limited in their ability to tolerate low voltages, therefore cannot be used in many rural areas where low voltage is characteristic. These lamps are unable to start up under low voltage circumstances. Low voltage, in rural areas, also happens to be common during early evenings, the period during which light is usually required most.

However, the good news is that several technological advances have made their way in the recent past rendering consumers a better choice in LFLs. Firstly, there are new LFLs with a warm white light – quite similar to the warm and lively colour produced by a normal bulb. There are also shorter and slender versions of the tube. The new low voltage tolerant units are capable of not only starting under quite low voltage conditions but also allowing the users to dim the light appropriately to required levels. In essence, LFL coupled with the advancing electronics, offers, low voltage tolerant, high efficient and dimmable units. The slender and the smaller the tube becomes the lesser the number of watts it consumes.

The LFL is a slightly complex device, having two or more components than the light emitting tube, namely the starter and the ballast, popularly known as the choke. The ballasts are of two major types, magnetic and electronic. The magnetic ballast can warrant the fullest efficiency of an LFL, but at the cost 30 Watts or more. They are in fact substandard units, comprising of aluminium wire components instead of the low resistance, yet expensive copper wire. A good ballast consumes only 8 – 12 Watts. An electronic ballast is far lesser than this, even lesser than the power you can measure. Hence, beware of the cheap ballasts. One thing is that their faults become evident only when they are in use. Secondly, they emit more heat and noise than light!


Compact Fluorescent Lamps (CFL)

CFLs are a mix breed between the IFL and LFL, where the technological features of the LFL is neatly packaged into a unit so easily interchangeable with an IFL. The CFL technology offers warm white lamps in a wider scale as it aims at replacing IFLs. This device is nothing but the same LFL, yet with a bent tube, offering it the luxury of a compact size. The unit is termed ‘self ballasted’ as the electronic ballast is contained within the bulging ceramic piece between the tube and the electrical connector. The luminous efficacy of this device is around 60 lumens per Watt of electricity, little less than the LFL, resulting from the loss of light from the self shadowing effect of the bent tube. These devices are used by more than 50 % of the urban consumers and 20 % of rural consumers at present. A major problem associated with the CFLs is the influx of substandard lamps into the country by unscrupulous importers. However, Sri Lanka Standards Institute (SLSI) now performs a mandatory import inspection of all consignments of CFLs, controlling this situation to a great extent. Further the Sri Lanka Sustainable Energy Authority (SEA) is to introduce an energy label for CFLs very soon, offering the discerning consumer to choose the best CFL from the better units filtered by the SLSI.

Light Emitting Diodes (LED)

Also referred to as solid state lighting, this technology offers a very high level of luminous efficacy, presently in the range of 100 lumens per Watt. Early LEDs emitted only red or green light, but later still they were combined to give a yellow hue. In the past, this technology mainly catered to the indicator lamp market, as coloured light had very limited applications in space lighting. However, in 1990’s a special coating technology was developed which was able to transform the light emitted from an LED to be converted to white light through a florescence effect. With this breakthrough, producing all the colours in the spectrum including white light became a possibility. This warranted a new age of solid state lighting, particularly suited for a variety of purposes including space lighting, sinage lighting, automobile lighting and even aesthetic lighting.

The prospects of LED lighting is the very long life cycle of projects, often in the range of 50,000 hours compared to the best CFL which will last around 6,000 hours. The drawbacks in white LED based lighting are the high cost, high intensity heat it generates in creating the light energy - requiring bulky and expensive heat sinks, the dependence on a chemical coating which can deteriorate with time, low power ratings, requirement of many auxiliary devices and high directionality of individual light sources. These properties however may limit the use of white LEDs in the immediate future. But their prospects remain bright in the horizons. If research in LEDs continue intensely, the world over becomes successful in creating a luminous efficacy in the range of 150 - 200 lumens per Watt, which will undoubtedly propel our future into a revolutionary LED illumination era.


The writer is the Deputy Director Generals (Operations) of the Sri Lanka Sustainable Energy Authority.

Email: info@energy.gov.lk

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