World Bank Development indicators database that had data for both variables in 2010.
For the countries in the lowest fiftieth percentile of life expectancy the average life expectancy is 66 years and per capita energy use is 74% of the global average. For those countries in the top fiftieth percentile life expectancy at birth is 78 years and per capita energy use is 212% of the global average.
There are no doubt some distortions introduced into an analysis of this type due to the use of countries as the unit of analysis. Each country of course has a distribution of life expectancy and energy use within its borders. It would be ideal to have a dataset with the individual as the unit of analysis, but I suspect that such data is not soon forthcoming.
Nonetheless these data carry a powerful message -- Energy poverty is not the only factor which contributes to below-average life expectancies, but it is clearly a very important factor.