Which devices are the most energy intensive?
Posted by Alex Barrett on 25 April 2017 at 3:31 pm
We live our lives surrounded by devices. We work on computers, carry phones and tablets with us wherever we go. Kitchens are full of fridges, freezers, microwaves and washing machines. Some are more energy intensive than others, but all of them are contributing to high energy bills, and higher carbon emissions. So which are the main culprits?
Estimates of energy cost are easy to find, but vary a lot depending on the price of electricity and the amount of time a device is assumed to run. Different models will use different amounts of energy. Some figures from the Energy Saving Trust are quoted below  and give us a general idea of our average energy use. Some alternate estimates are also linked for comparison [2, 3, 4]. Similar sites can estimate the carbon footprint associated with different technologies and are also worth a look [5, 6].
Unsurprisingly fridges and freezers are the most energy intensive of our kitchen appliances. They are constantly running, so use a lot of power. A fridge freezer is estimated to use 427 kWh per year. Standalone fridges use slightly less than standalone freezers, 162 kWh, compared to over 300 kWh. Electric ovens can use up to 317 kWh, depending on the type. Microwave ovens are relatively less energy intensive using around 56 kWh.
How about televisions and computers? It depends on the type of device. An LCD television uses 199 kWh per year, while a plasma TV is massively more expensive. Adding set top boxes, DVD players and speaker systems also increases the cost. Desktop computers are considerably more energy intensive than laptops, using 166 kWh compared to 29 kWh. A wireless router uses 58 kWh, and unlike many of these electronic devices, it does generally need to be left running, unless nothing is going to need to connect to the internet for a while.
Of course if you are connecting your computer to the internet then you are interacting with many more computers scattered across the world. It has been estimated that there are 100 million servers in the world, connecting 750 million laptops and over a billion smart phones . A study from the University of Berkeley  estimates that running the internet uses 107-307 GW, around 30,000 kWh, every second. This is around 2% of global electricity production. The carbon footprint of the internet has been estimated to be around 300m tonnes of CO2 , or around 1% of global greenhouse gas emissions.
So what can we do about this? Should we switch everything off? The answer is broadly: if you can then yes. Some devices clearly can’t be shut down every night to save power. If we switch our fridge freezer off then it won’t keep our food cold. Shutting down internet servers clearly isn’t feasible, but we can certainly switch off our router when no one is in the house. It’s not very original to say “don’t leave things on standby”, but it is certainly true. Computers and televisions are very energy intensive compared to most other devices we use, particularly when they are connected to printers, speakers, routers and other paraphernalia. There is no reason to leave these on when they aren’t in use, so this can make a big difference to our energy usage.
- This is Money
- Switch Energy Supplier
- The Telegraph
- Frequency Cast
- Reduce Your Carbon
- New Scientist
- University of Berkeley (links to pdf)
- The Guardian
Image credit: Lucy Crosbie, Flikr
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