Microwave ovens could be as bad for the environment as cars, suggests new research.
The use of microwaves across the European Union (EU) alone emits as much carbon dioxide as nearly SEVEN MILLION cars, according to the study.
University of Manchester researchers conducted the first ever comprehensive study of the environmental impacts of microwaves, considering their whole life cycle - from 'cradle to grave'.
They found that microwaves emit 7.7 million tonnes of carbon dioxide equivalent per year in the EU, the same as the annual emissions of 6.8 million cars.
The findings also show that microwaves across the EU consume an estimated 9.4 terawatts per hour (TWh) of electricity every year, the equivalent to the annual power generated by three large gas power plants.
The researchers say that efforts to reduce consumption should focus on improving peoples' awareness so they use their ovens more efficiently.
Massive micro sales
Microwaves account for the largest percentage of sales of all type of ovens in the European Union, with numbers set to reach nearly 135 million by 2020.
But the scale of their impact on the environment was not known until now.
The study used life cycle assessment (LCA) to estimate the impacts of microwaves, taking into account their manufacture, use and end-of-life waste management.
The researchers investigated 12 different environmental factors - including climate change, depletion of natural resources and ecological toxicity.
The research shows that the main environmental 'hotspots' are materials used to manufacture the microwaves, the manufacturing process and end-of-life waste management. For example, the manufacturing process alone contributes more than 20 per cent to depletion of natural resources and to climate change.
But the findings show that it is electricity consumption by microwaves that has the biggest impact on the environment, taking into account its whole life cycle, from production of fuels to generation of electricity.
The study found that, on average, an individual microwave uses 573 kilowatt hour (kWh) of electricity over its lifetime of eight years - the equivalent to the electricity consumed by a 7 watt LED light bulb, left on continuously for almost nine years.
Researchers say that is despite the fact that microwaves spend more than 90 per cent of their lifetime being idle, in the stand-by mode.
They suggest that initiatives to reduce consumption should focus on improving awareness so they are used more efficiently. For example, reducing electricity use by adjusting the time of cooking to the type of food.
The researchers said that waste is another major problem. Due to their relative low cost and ease of manufacture, people are throwing more electrical and electronic (EE) equipment away than ever before, including microwaves.
In 2005, across the EU, 184,000 tonnes of EE waste was generated from discarded microwaves. By 2025 this is estimated to rise to 195,000 tonnes, or 16 million individual units being sent for disposal.
Dr Alejandro Gallego-Schmid said: 'Rapid technological developments and falling prices are driving the purchase of electrical and electronic appliances in Europe.
"Consumers now tend to buy new appliances before the existing ones reach the end of their useful life as electronic goods have become fashionable and 'status' items.
"As a result, discarded electrical equipment, such as microwaves, is one of the fastest growing waste streams worldwide.'
He said another major contributing factor to the waste is a reduced lifespan of microwaves. It is now nearly seven years shorter than it was almost 20 years ago.
Research shows that a microwave's life cycle has decreased from around 10 to 15 years in the late 90s to between six to eight years now.
Dr Gallego-Schmid added: "Given that microwaves account for the largest percentage of sales of all type of ovens in the EU, it is increasingly important to start addressing their impact on resource use and end-of-life waste."
The study also suggests that existing regulations will not be sufficient to reduce the environmental impacts of microwaves.
It recommends that it will be necessary to develop specific regulations for microwaves, targeting their design.
The researchers say that will help to reduce the amount of resources used to make microwaves and waste generated at the end of their lifetime.