Methodology for Country Lighting Assessments

There are two modelling approaches that are used to estimate the installed stock of lamps for each country. The first approach develops an installed stock base from three different data sources. The second approach estimates the installed stock of lamps based on an assumed proportion of national electricity consumption for lighting in a given country. These two approaches are combined to generate the total estimated installed stock of lamps for each country.

Approach 1: Estimate of Lamp Stocks

The first approach for estimating the installed stock of lamps in each country uses three methods:

1a: Estimating the installed stock of lamps based on apportioning regional estimates of the installed stock provided by en.lighten Partners OSRAM and Philips.

1b: Estimates of the national stock provided by the country through the use of a survey tool that was prepared and circulated. The questionnaire has seven parts, including detailed questions on the national lighting market.

1c: Stock model calculation based on imports and exports. The modelling team gathered a six-year time series for lamp shipment data to each country from the UNComtrade system. The team then applied estimates of lamp lifetime and operating hours, to convert the shipments into an installed stock.

Note: Approach 1c does not apply to countries with domestic production because data is not currently available on the proportion of domestic consumption derived locally or the proportion of exports.

Approach 2: Estimate of Electricity Share

The second assumes that lighting accounts for approximately 15 per cent of total national electricity consumption. Given this level of annual demand and estimates of the operating hours and lamp wattages, an installed stock of lamps is determined across the lamp technologies and end-use market segments which would be adequate to represent that level of electricity consumption.
Note: If a country already supplied en.lighten with its approximate share of electricity consumption for lighting, the starting estimate is adjusted to match the country’s estimate.

The shares of the installed lamp stock of lamps by end-use market segment and technology for this approach were derived in two ways:

2a: Apportion electricity consumption for lighting using the country lighting questionnaire(s) for a given region.

2b: Apportion electricity consumption for lighting using the same proportions found Approach 1.

Combining Approaches 1 and 2

The results of the two approaches are averaged together for the installed stock of lamps in each country. The energy consumption associated with this baseline is calculated and then the baseline is converted to energy-efficient lamps according to the percentages shown in the Table below regarding the efficient lamps that will replace the existing stock of lamps. The Table shows the one-for-one lamp technology substitution for each lamp in the existing stock and each energy-efficient lamp that would replace it. Under the efficiency scenario, each lamp listed in the top row is replaced by a more energy efficient lamp (types listed in the left column), according to the percentages shown in the columns. For example, 10% of the existing incandescent lamps in a country are replaced with incandescent lamps, 85% are replaced with compact fluorescent lamps and 5% are replaced with light emitting diode lamps. These assumptions are applied equally to all sectors and all countries.

Table 1: Assumptions for lamp technology substitution