A company's value can be attributed to its workforce, or the machines it owns, or factor productivity (the value that it extracts from its workers and machines). A small company may be a smaller copy of a large company if they have, for example, one hundredth of the number of workers and machines in the large company, but use them in the same way.
In Burundi, many companies have big problems with electricity supply, and some have private generators to produce electricity. Here is the percentage of electricity produced by generators for small, medium, and large companies in the capital Bujumbura (company size is classified by numbers of employees):
Source: World Bank Enterprise Surveys
Smaller companies in Burundi produce lesser shares of their electricity using their own generators. They are not just small large companies, they use different machines and so probably have different productivities from the machines they use.