Voltage Matters! Brazil's III-Fitting Lamp Standards
Voltage Matters! Brazil's III-Fitting Lamp Standards
In Brazil, there are several electric grids that supply electricity at
different voltages in different areas of the country. When lamp standards
were changed to allow fewer voltages of incandescent lamps, this had a
negative impact on energy consumption, the society's economy, and household
finances. Guest authors Gilberto De Martino Jannuzzi and Cesar Josˇ Bonjuani
Pagan explain the problem.
In Brazil, the penetration of efficient lighting technologies - compact
fluorescents and other fluorescent technologies - is increasing as a result
of some utility-sponsored programs and better marketing. However, incandescent
lighting is still predominant. Incandescent lamps account for about 93%
of electrical energy consumed in the residential sector and about 50%
of lighting electricity used in the commercial sector.
The country has a total of about 35 million households connected to the electrical grid at 110, 115, 120, 127 and 220V. The diversity of tension poses various difficulties to manufacturers of lamps and other electrical equipment, because most equipment needs to operate in a wide range of voltages (110Š127 and 220V). Nominal voltage diversity is not the only problem, however. In some areas of the country significant voltage fluctuations negatively impact the life of the electrical equipment.
About 60% of the households are in areas using 110Š127V; the remaining 40% use 220V. Nearly half of the households are served by the 127V grid. Roughly 60% of the 300 million lamps sold annually in the country are used in areas served by the 110Š127V grid.
The new standard imposed in 1996 by the Brazilian Association of Technical Standards (Associação Brasileira de Normas Técnicas, ABNT) for incandescent lamp manufacture (known as the norm NBR IEC-64) includes only specifications for the 100, 110 and 120 V for E-27 socket incandescent lamps. (220V lamps are subject to a different standard.) Regions served at the 127V(covering about half of the present population) had to use a lamp designed to operate with optimized parameters at the 120V level. Before the new standard was implemented, households served by the 127V grid, for example, could purchase lamps manufactured to operate at this tension and expect similar lamp life, energy consumption and lumen output as other households from other voltage areas.
This change in the standards triggered significant alterations in the lighting load of the regions served by the 127V grid. The new standard caused different economic impacts on the various stakeholders: customers, utilities, lamp manufacturers and the society as a whole.
120V VERSUS 127V
The incandescent lamp produces light by heating a tungsten filament that rests inside the glass bulb filled with a mixture of gases such as argon and nitrogen at low pressure. Higher voltages (leading to higher temperatures) will yield more light, but this will accelerate the evaporation of the tungsten element and therefore will limit the lamp life. The incandescent lamp has to provide a certain light output during a specified lamp life under specified electrical conditions (voltage). It can be operated in several different voltages, but the amount of light and the lamp life will vary greatly with the voltage.
In order to present the effects of different electrical tension on an incandescent lamp, let us consider two lamps with the same nominal wattage, one projected to operate at 120 and the other at 127 V. When subjected to the same electrical tension V, incandescent lamps have their real wattage (effective power) P expressed as:*
This means that a lamp designed to operate at 120V will have an energy consumption 9.1% greater than a lamp projected to operate at 127V, when both are submitted to the same voltage.
Similarly, these two lamps, which were designed to have the same life L when operated at their original voltage (120 or 127V), will experience a significant change on L when different tension is applied. The literature shows that a lamp designed to operate in 120V when submitted to a 127V tension will have a 45% lower life:
On the other hand, a lamp designed to operate at 120V will give more lumen output (f) when used at 127V:
As previously mentioned, there are, in practice, fluctuations in tension in the country. The permitted variation ranges from 106V to 121V for the areas served at 115V, and from 116 to 132V for the areas served at 127V (DNAEE, 1978).
Lamps designed to operate at 127V will experience a decrease in the light output level when used in the 115V grid. In the extreme case when the voltage is allowed to drop to 106V, the luminous flux of a 100W lamp is less than the nominal value of the 60W lamp.
SOCIETAL EFFECTS OF THE NEW STANDARD
Table 1 shows the evaluation of luminous flux, effective power and life for 60W and 100W lamps according the permitted levels of tension variation. The use of an incandescent lamp according to the new standard not only increases the electricity consumption but also requires more peak capacity, as Table 1 demonstrates. Assuming that 80 million lamp sockets use 60W bulbs and 40 million use 100W bulbs in the 127V areas, we calculated that an additional peak demand capacity of 665 MW is required and that 1.32 GWh per year more electricity for lighting will be consumed. Compared to the baseline case, an additional 118 million lamps will be bought annually by households to compensate for the reduced lamp life. The costs for increasing the generation capacity needed to operate these lamps are about US$2000/kW.
A lamp designed for 120V operation will have its life reduced to roughly half of its nominal life when at 127V, thus consumers' costs for lamp purchases are doubled under a given period of time. The additional lamp purchases can be translated into an increased cost for lighting services by $0.11 and $0.07 for each kWh used by a 60W and 100W lamp, respectively. These are the additional costs to maintain the baseline lighting requirements with the old standard. From a societal viewpoint, not only will more resources be spent in the production of lamps, but more electricity will also have to be produced.
To evaluate the consumer perspective, it is necessary to include the effects of electricity tariffs in addition to the lamp cost. The new standard represents additional costs to households, which can vary from $1.61 to $2.80 depending on tariffs and lamp wattage for each lamp socket and year.
EFFECTS ON UTILITIES
In the case of the power sector, the results are mixed depending on whether the consumers are paying high tariffs or average tariffs. We assume that 70% of the electrical energy used for lighting is consumed during peak hours at a cost of $150/MWh and the remaining 30% during off-peak period at a cost of $20/MWh to the power sector. The lamps sold under the new standard increase electricity sales. In the case of lamps being used by consumers paying the high tariffs for each 60W lamp the power sector will have an increase of $1.09 per year. This value is even higher for the 100W lamp, $1.82. In the case of consumers paying the average residential rate, the values are $0.63 and $1.04 for the 60W and 100W lamps, respectively.
However, if we on the one hand assume that the marginal electricity production costs for peak periods are $150/MWh, the net annual benefit for the lamps used by households paying the average tariff is negative for the utilities. On the other hand, the power sector earns net gains in the case of consumers paying the higher rates. A net transfer of resources from consumers to utilities is caused by the new standard in several cases, but the utilities are also facing costly needs for increased peak capacity.
THE MANUFACTURER PERSPECTIVE
Sales of incandescent lamps must have increased in the areas served by the 127V grids, as our results from the previous sections indicate. Also, economies of scale were most likely achieved by the simplification of production lines and stock and distribution costs for the manufacturers. We have not been able to get data on lamp sales or on industrial production costs of the average lamp sold today for comparison with the data from before the enforcement of the new norm. However, significant resources seem to be transferred from consumers and society to the lamp manufacturers.
The Brazilian Association of Lighting Manufacturers (ABILUX) supports the new standards and emphasizes that customers at 127V now benefit from the higher lumen output of their lamps. They say that customers' purchases in the past have shifted towards lamps of higher wattage as result of the poor performance of the electrical system. Data presented by ABILUX show indeed that the average lamp sold has increased by 8W in the areas with tension 110-115-120-127 volts in the period from 1988 to 1997. This migration towards lamps of higher wattage has not occurred in the areas of 220V, which have a more reliable service. However, this trend has not been halted after the enforcement of the new norm.
AN APPROPRIATE SOLUTION?
The incandescent lamps sold in a significant part of the country today are consuming 9.1% more electricity and lasting 55% less longer, compared to the ones available two years ago. Assuming no significant changes in consumer behavior with regards to lamp use, these lamps have added an amount equivalent to about 0.44% of the total electricity consumed in the country. This value is comparable to the amount of savings achieved by the daylight savings achieved during the summer months in the southern part of the country.
The economic impacts are significant and do not benefit customers, the society as a whole or the utilities. ABILUX, as well as other electrical appliancesÕ manufacturers, rightly points out that the diversity of tensions and tension fluctuation are obstacles for producing more efficient equipment. However, the arguments that the new norm will prevent households from shifting towards higher wattage lamps seem weak. We hold the view that the problems of the electricity distribution system deserve the merit to be solved independently, and should not serve as basis for technical product standards.
This story ended happily, however: The matter was brought to the attention of the federal government and, as of January 2000, an incandescent lamp more suitable for lasting longer when operated in the 127V areas was introduced again in the market. A revision of the 1996 ABNT standard was also requested and is now being implemented.
Gilberto De Martino Jannuzzi
Cesar Josˇ Bonjuani Pagan
Both authors are with the University of Campinas, Brazil. More detail on the assumptions are found in a longer paper by the authors: Energy Public Goods: the case of incandescent lamp manufacture in Brazil, available at www.iaeel.org
jannuzzi@fem.unicamp.br
pagan@fee.unicamp.br
* Kaufman JE. IES Lighting Handbook. 4th edition. Illuminating Engineering Society. New York, 1996.