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Table 4.2. Annual Energy Use by Number of Students in Household Lighting Students in Household (no.) 0 1–2 3–4 >4 Average
Kerosene (liter) 23 28 34 37 27
Grid Electricity (kWh) 52 84 121 232 81
Domestic Uses Kerosene (liter) 25 30 36 40 29
Grid Electricity (kWh) 92 153 209 415 144
Source: BIDS Survey (2004).
Indeed, compared to electric lighting, use of kerosene lamps varies considerably less by number of students (see Table 4.2). The most plausible explanation for such increases in electricity use is that schoolchildren use electric lights to extend their study time. According to the survey, students in households with electricity study longer (see Table 4.3). Total hours of study time (both daily and evening-hour) are greater in households that use electric lighting versus those without electricity, which use kerosene lamps. Clearly, electricity contributes to human-capital formation, leading to a longer-term increase in productivity.
Moving to Better Lighting: Consumer’s Surplus In rural Bangladesh, the most common household lighting appliances are kerosene-using kupi and hurricane lamps and electricity-using incandescent bulbs, fluorescent tubes, and compact fluorescent lamps. In this study, households were categorized into three groups: (1) those that light only with kupi lamps, (2) those with hurricane lamps that may or may not own a kupi lamp but do not have electricity, and (3) those with electricity that sometimes use an electric lamp and may or may not use any type of kerosene lamp. The gains in consumer’s surplus were estimated for the transition from the kupi- to the hurricane-based system, and from the hurricane- to the electricity-based system. To understand the results of the estimates of welfare gains, it is necessary to observe the distribution of households by their lamp-holding characteristics. This study’s findings indicate that kupi-based households are concentrated more among poorer households (see Table 4.4). Table 4.3. Study Time by Household Hurricane lamp holdings are far more common Electrification Status than kupis, and patterns across income classes are (average number of hours) not clearly discernible. Households with electric Household Status lamps are about 29 percent of households, Student With Without reflecting those that have electricity; and their Study Time Electricity Electricity proportion increases with income. Daily 2.72 2.13 One conservative measure of the improveEvening 1.32 0.96 ment in consumer welfare is avoided expendiSource: BIDS Survey (2004). tures from switching from kerosene to electricity