Producing electricity from urban solid waste could provide energy for up to 40 million African households in 2025, according to a study co-authored by the European Commission Joint Research Centre (JRC).

In a report published in Renewable and Sustainable Energy Reviews, JRC researchers determined the potential of recovering energy from trash by using landfill gas and waste incineration, and found that it could have provided more than 20 percent of the continent's total energy consumption in 2010. 

Where there are humans, there's trash, and an awful lot of it, too. Over the past century, we somehow managed to increase our annual waste generation 10-fold, going from producing 110 million tonnes per year in 1900, to 1.1 billion tonnes in 2000. By 2025, household trash could amount to a staggering 2.2 billion tonnes each year globally. 

With its booming population, economic growth and increasing urbanisation, Africa is currently struggling to tackle the growing amounts of refuse that accompany development - a lack of infrastructure and environmentally friendly options is hampering the efforts countries take to make sure trash doesn't become a massive problem in Africa's future. Especially in rural areas, garbage is often simply burned without regard for pollution, or dumped in landfills without protecting groundwater.

"The poor waste management in Africa has important consequences for the disposal of uncollected waste in dumps and the associated severe environmental and health related problems," the authors note. "Improvements in waste management are needed [and] the use of the energy content of waste could be one of the leading ideas for such progress."

There are two ways in which urban waste in Africa can be used for energy production, and both involve fire. Waste-to-energy (WTE) incineration plants use burning trash to produce steam for generator turbines. They are especially popular in Europe, which boasted 472 such facilities back in 2010, out of over 600 found around the world.

However, they are not suitable for all African cities, because WTE plants are expensive to build and require stringent emissions controls to avoid polluting the atmosphere with toxic by-products.

For now, most cities in Africa generate large amounts of organic waste, and bury them in landfills. As stuff decomposes, these landfills generate a cocktail of polluting gasses - especially methane and carbon dioxide. If these gasses are captured and filtered, they can be burned in gas turbines, internal combustion engines, and steam boilers to generate electricity.

In their report, JRC researchers estimated that through proper waste management a whopping 83.8 TWh of electricity required by the continent in 2025 could be generated from trash.

While the information is theoretical and actual numbers would depend on the type of waste collected, as well as how efficiently the energy recovery was performed, it's clear that smart use of trash could alleviate energy poverty in many African countries, where millions of people still don't have access to the grid.