Greenhouse effect

Generating energy from waste

A group of scientists in Chile want to extract energy and heat from trash. Their approach can minimise greenhouse gas emissions and thus support sustainable development.

The way to achieve all of the goals is to use the methane gas that is generated naturally in the decomposition process of solid waste in any landfill. Waste can thus become a source of energy. A variety of by-products can be obtained as well, but extracting methane is a very important aspect of recycling. This technical approach is state of the art in Germany and many other countries. It makes sense to adapt it to local needs.

Christian Seal, director of the Department of Civil Engineering of the Universidad de Santiago, says that methane can replace coal or oil for various purposes. Decomposing garbage generates two gases that cause climate change, carbon dioxide (CO2) and methane. Seal says his team wants to maximise the use of methane for energy purposes. Currently, both CO2 and methane are emitted into the atmosphere.

Anaerobic microorganisms practically “eat” garbage and transform it into biogas, and a good option is to harvest the methane for electricity production. The scientist speaks of “a third-generation biofuel”. The first and second generations need extensive agricultural land, cultivating maize or other plants for fuel production. In his eyes, it is preferable to produce fuel from garbage – including rotting wood, cow dung or man-made trash.  

Another scientist from the same University, René Garrido, points out another advantage: “Maximising methane production from waste means to change metabolic reactions and thus  reduce CO2 generation.” The approach can thus limit the emission of both greenhouse gases.  

Oil, coal and natural gas are fossil fuels that are really only transformed organic matter from the dinosaur age. The main component of natural gas is methane. Burning it sets free CO2. However, methane is a far more potent greenhouse gas than C02. “One molecule of methane causes the same damage as 26 molecules of CO2,” the scholar says. Burning it means it is never emitted into the atmosphere. Generating energy this way thus serves climate protection even though the captured carbon is eventually emitted.


Tomás Parker Cerda is a journalist and political scientist. He lives in Santiago, Chile.


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