How can energy consumption be an indicator of per capita availability of capital? "An important indicator of low capital per head available in developing countries is the consumption of energy". I could not decipher the concept.
In economics, capital refers to things that are used to produce other things. 

So, capital includes tangible things like a delivery truck, an office building, or a factory. These are things which often require energy to run.

Hence, if a developing country has low capital per head, then it probably also has few delivery trucks, office buildings, and factories. And hence, it probably also has lower energy consumption.