Households are using less energy

Internet usage accounts for only 0.5% of an average Briton’s daily energy consumption 

Guildford, Surrey – 24 June 2013 – As the consumer appetite for digital content continues to grow, many commentators have been worried about the environmental impact this surging demand for media consumption is creating. Both in housing this data in data centres, for example Facebook alone handles 300 million photo uploads per day, as well as consuming this data through cloud services used at home and via ‘connected’ mobile devices on the go.

However, new research findings released by ESP KTN members  Professor Paul Krause & Kate Craig-Wood looking at the energy cost of internet mediated transactions, such as downloading an album from iTunes or streaming a film, have shown that households are actually using far less energy to maintain their digital lifestyles than originally thought.

Previous research suggested that in the public cloud, end user access over wireless networks uses ten times as much energy as the data centre! However a key finding of this new research revealed that the energy consumed in networks is utterly inconsequential to the energy consumed at the data centre and the energy consumed in the home (for general cloud services).

Further, for high-bandwidth activities like media streaming almost all the energy is consumed in the home; 93 of the total in the case of media streaming to a smart TV, most of which is the embedded energy of the TV itself.

When considering mobile Internet energy consumption it is again dominated by the user-end, with the mobile phone's energy of manufacture accounting for 67%. By comparison the mobile base station was estimated to account for less than 2% of the total.

Putting this into perspective when looking at our daily carbon usage, the average home broadband usage is 23GB/month, which becomes 2,000 Wh/day based on the laptop user model. The average Briton consumes 195,000 Wh/day of energy and there are on average 2.3 people per household, so online activities account for perhaps 0.5% of our total energy footprint.  The energy of our online lives is inconsequential compared to the great benefits to society.

Kate Craig-Wood, MD of Memset, who conducted this research as part of her PHD looking at cloud computing in relation to climate change, said:  "This research has allowed us to clearly demonstrate that ICT is not the enemy; a typical Briton spends perhaps 0.5% of their daily energy consumption on Internet services, including everything from the data centre to the laptop. Given that ICT is expected to save 16% of societal emissions by 2020 and the sector already contributes 10% to GDP, the climate impact of our industry is clearly not a significant concern at this stage."

"We are doing further work to explore the dangers of the rebound effect and hope to build a model of ICT services' future energy requirements growth. Early results are encouraging, suggesting that efficiency improvements in ICT services (similar to Moore's Law) is roughly offsetting the increase in demand due to price elasticity," concluded Craig-Wood.

Professor Krause said: “We clearly are seeing a massive growth in the use of wireless networks for music and video streaming and downloading. But this is replacing the purchase and use of physical media, which is a much more energy intensive activity.”

“Our analysis yields a figure of 1592 Wh/GB for the energy consumed (embedded plus in-use) in transferring data from a regional data center to an end user (based on the average British bandwidth consumption of 23 GBytes per month). This is significantly lower than earlier published estimates, but this difference can be accounted for by efficiency gains over the last seven years. Our analysis demonstrates that this energy budget is dominated by the figures for the data centre and the interface between ISP and consumer/office. It is possible that these efficiency gains are being countered by increased resource consumption. However, these additional Internet mediated activities often replace other activities with significantly higher energy budgets,” he concluded.

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Notes To Editor:

The key figures from the research are (all include both use phase and embedded):

• General cloud services delivered by a home broadband link consume 2,668 Wh/GByte (including laptop and home network

?       Of that figure, 33% is at the data centre (servers, NOC & M&E plant) and 59% is the home equipment (phoneline, modem-WAP & laptop)

?       For perspective, the average home broadband usage is 23GB/month, so that becomes 2,000 Wh/day. Theaverage Briton consumes 195,000 Wh/day and there are on average 2.3/household, so internet activitiesaccount for perhaps 0.5% of our total energy footprint

• General cloud services delivered via a mobile consume 3,908 Wh/GByte.

?       Of that, 74% is the phone and of the phone, 90% is the embedded energy.

• Media streaming services are more efficient, using about 637 Wh/GByte

?       Of that, 78% is the home WAP (wireless access point)

?       If you include everything in the media streaming model, inc the Smart TV, the figure is 2,018 Wh/GB

?       Of that 93% is at the user end (phone line, modem-WAP and smart TV

In the paper we discuss other research. The numbers are coming out significantly lower, which can in part be attributed to Moores-law like improvements.