Microwave ovens as costly as seven million cars

The carbon dioxide emissions associated with microwave ovens in the European Union is equivalent to that of nearly seven million cars, a UK study has found.

The study, made by a team led by Alejandro Gallego-Schmid from the University of Manchester, reveals that microwave ovens – popularly regarded as benign kitchen implements that are used for only a few minutes on any given day – collectively burn through 9.4 terawatt-hours of electricity each year – equivalent to the output of three large gas-powered power plants.

There are roughly 130 million microwaves in the EU, with the figure rising each year. In total, the researchers found, they emit the equivalent of 7.7 million tonnes of carbon dioxide

To calculate the figure Gallego-Schmid and colleagues conducted a full life-cycle analysis of the machines, including the energy expended in their manufacture, use and processing as waste at the end of their average eight year operational span.

Environmental costs were heaviest during the manufacture and disposal phases of the cycle. In 2005, for example, dead microwaves accounted for 184,000 tonnes of electronic equipment waste.{%recommended 3920%} 

Power consumption was highest during the operational phase. A single microwave during its life consumes roughly the same amount of electricity required to keep a seven watt LED light bulb burning continuously for nine whole years. That might not sound too excessive, until you consider that microwaves are idle for 90% of the time. 

The researchers note that de-carbonisation of EU electricity generation in coming years, together with regulations aimed at decreasing the use of “stand-by” functions, will reduce microwave impacts by as much as 25% by 2020.

However, other factors may well offset that gain. The team notes that the average operational life of microwaves – by far the most popular type of oven in Europe – has fallen by about five years in the past two decades, and continues to shrink.

“Given that microwaves account for the largest percentage of sales of all types of ovens in the EU, it is increasingly important to start addressing their impact on resource use and end-of-life waste,” says Gallego-Schmid.

The research is published in the journal Science of the Total Environment.