New Halogen Threat
New Halogen Threat
A new generation of mains-voltage halogen reflector lamps designed to compete with low-voltage halogen lamps promises cheaper and simpler residential luminaires. But the new lamps are far less efficient, and if luminaire manufactures pick up the lamp on a large scale, energy consumption in Europe could rise by tens of terawatt hours.
Table 1
Table 2
The story began more than a year ago when SLI introduced a mains-voltage MR16-type of small reflector halogen lamp with a new pin base called GZ10. This spring, Osram and Philips followed suit, and the message from lamp-makers was clear: For example, "because the lamp can be connected directly to the mains supply, the use of bulky and costly transformers is not necessaryÉ (the lamp) offers benefits for both consumers as well as for luminaire manufacturers", Philips says in a brochure distributed at the Hannover fair.
The new lamp is about half as efficient as a standard low-voltage reflector lamp (see Table 1), and compared with the infrared-coated (IRC) low-voltage reflector lamps, also newly introduced, its efficacy is lower by about a factor of four.
Over the last 15 years, small low-voltage halogen reflector lamps have become very popular, especially on the European market. Most European households have one or more luminaires for these lamps, and the ownership rate is increasing.
Halogen lamps are inherently more efficient than standard incandescent lamps, but still less efficient than compact fluorescent lamps (CFLs) and other discharge lamps. One may wish that CFLs be used instead of halogens, but in many cases CFLs cannot easily replace halogen lamps. For instance, reflector halogen lamps are especially well-suited for small spotlights and accent lighting, while other small halogen lamps are often preferred because of their minimal size. Moreover, their light quality and color rendering are excellent, and they can easily be dimmed. (In the case of torchieres, CFLs could easily replace the high-wattage halogens since this type of luminaire provides indirect lighting, and lamp size is not a decisive factor. See IAEEL 1/96.)
Although the halogen lamp burns more efficiently at 12-V than at 230-V, transformer losses can be substantial. Losses are generally higher from a conventional transformer than from an electronic one, but the latter typically have higher stand-by losses. Although transformers can be rather bulky and heavy, the trend is slowly going towards smaller size and increased efficiency. The most efficient electronic transformers on the market have losses below 5 percent. The efficiency of future transformers should be even higher, and stand-by losses should become insignificant (for instance, see article on page 11).
ENERGY ASSUMPTIONS: TEN YEARS AHEAD
Luminaires made for the new 230-V reflector lamps will compete directly with those made for low-voltage reflector lamps in the residential sector. Because of their poor efficacy, penetration in the commercial sector will probably be limited to very small establishments.
To estimate the cost of these new lamps in terms of increased energy consumption, we developed a residential scenario based on the following simple assumptions: First, residential luminaires are often designed to be built as cheaply as possible; thus the replacement rate is high. Moreover, the number of luminaires per household is rising slowly. Second, the torchiere market success shows that a new luminaire concept can penetrate the market extremely quickly, and these new lamps tie into a halogen tradition that has already been established. Since the very idea behind these new lamps is to help manufacturers produce simpler and cheaper luminaires, this factor should also foster quick market acceptance.
According to our scenario for Europe as a whole, the mean number of luminaires dedicated for GZ10 lamps will be slightly less than three by 2008, with a total stock of 400 million units. (There are ~150 million households in Europe. We assumed three per household in Western Europe and a lower average in Eastern Europe.) Today, the new lamps only exist in a 50-W version, and we have assumed that two new luminaires will replace (or be bought instead of) one low-voltage halogen luminaire. The last assumption is based on the fact that the new lamps produce half as much light as standard low voltage halogen lamps of an equivalent wattage. (More wattages will probably be introduced. This would mean fewer luminaries but roughly the same total load.)
We also introduce a high-efficiency halogen case where low-voltage luminaires are chosen, but highly efficient 12-V IRC lamps are used. In this case the number of luminaires is the same as in the standard 12-V scenario, but the lamp wattage is reduced. Although there is no 20-W IRC lamp in existence today, one has been announced. Judging from Table 1, a 20-W lamp might even replace a 50-W lamp, but we have conservatively assumed that consumers would use the 35-W lamp and enjoy higher levels of lighting instead. Finally, as a sub-scenario we have introduced an extremely efficient transformer with 0.5-W stand-by losses and running losses of 1W. The difference between the most efficient solution and the least efficient one is 18.5 terawatt hours per annum or US$ 2.8 billion in yearly residential energy costs (assuming an average residential tariff of 15 US cents). Since the European energy lamp label does not yet cover low-voltage or reflector lamps consumers receive little warning as to the consequences of their choices.
Nils Borg
Research: Susanne Bjšrn