Across the developing world but especially in sub-Saharan Africa and Southern Asia, rural villages and remote areas often lack direct connections to national electricity grids, locking them in poverty and underdevelopment.

But increasing numbers of countries are helping their people escape this energy trap by tapping an unexpected and previously underestimated resource: animal poop.

Poultry, pigs, sheep, cattle and other domesticated animals generate around 85% of the world’s animal faecal waste.

Converting all that livestock manure into biogas offers a way to make a renewable fuel source available to more than a billion people for domestic use, giving them access to affordable, reliable, and sustainable energy, according to World Livestock.

The approach is already widely in use in India and China.

Between 2003 and 2013, China built 42 million small household biogas plants run on chicken and cattle manure that provide light, heating and power, as well as a number of much larger biogas power stations with a daily capacity of 18 000-60 000 kWh.

By 2003, India had already installed some 3.4 million family-size biogas reactors in various isolated parts of the country and in 2015, the number of family-size biogas plants in India was reported to be four million. Other countries in Asia and in Africa are now exploring the use of biogas to expand household electricity production.