π Planet
How to reduce carbon emissions of the digital sector

Internet of Things: 50 billion greenhouse gas producers?

James Bowers, Chief editor at Polytechnique Insights
On September 22nd, 2021 |
4 min reading time
Screenshot 2021-09-22 at 16.33.18
Chantal Taconet
Lecturer in Computer Science at Télécom SudParis (IP Paris)
Key takeaways
  • Between 2015 and 2019, energy consumption of the global digital sector in the world increased by 6.2% per year.
  • In 2010 there were ~1 billion connected devices in the world, which will increase to 50 billion by 2025 and 100 billion in 2030.
  • Half of the energy consumption and subsequent emissions concerns production of objects, the other half their use.
  • Researchers like Chantal Taconet aim to evaluate appropriate lifespans of objects to maximise on the environmental benefits.
  • For her, one solution must be reducing the number of devices in use and on the production of new objects.

As the dig­i­tal econ­o­my sky­rock­ets, so does its envi­ron­men­tal impact. Respon­si­ble for 3.5% of green­house gas (GHG) emis­sions in 2019, the fig­ures for dig­i­tal have over­tak­en the avi­a­tion sec­tor (2.5% in 2018); a divide fur­ther accen­tu­at­ed by the pan­dem­ic. Between 2015 and 2019, ener­gy con­sump­tion of the dig­i­tal sec­tor in the world increased by 6.2% per year1, in part dri­ven by the soar­ing sales of wire­less devices like smart­phones, tablets, lap­tops, print­ers, TVs, oth­er indus­tri­al devices or even sur­veil­lance cam­eras. As we head towards 2025, pro­jec­tions show that GHG emis­sions of the dig­i­tal econ­o­my is like­ly to increase to as much as 5.5% (with a high risk of going beyond even that to reach 9%) and that wire­less devices have been labelled as an impor­tant avenue. 

Recent reports from The Shift Project point to the “Inter­net of Things” (IoT), the pletho­ra of con­nect­ed devices we use on a dai­ly basis, as one of the main caus­es of GHG emis­sions for the sec­tor. Of the cat­e­gories con­tribut­ing to the envi­ron­men­tal impact of the dig­i­tal sec­tor, con­nect­ed devices have shot up from caus­ing only 1% in 2010 to a pro­ject­ed 18–23% in 20252. Less sur­pris­ing when you con­sid­er that esti­mates from 2021 show, on aver­age, each per­son in West­ern Europe owns 9 dig­i­tal devices. And, whilst back in 2010 there were ~1 bil­lion devices in the world, accord­ing to var­i­ous esti­mates, there will be some­where between 30 and 50 bil­lion by 2025 and as many as 100 bil­lion in 2030. Hence, the glob­al data is clear – the num­ber of con­nect­ed devices is increas­ing expo­nen­tial­ly dri­ving up our dig­i­tal-fuelled envi­ron­men­tal footprint.

Focus on pro­duc­tion and usage

“GHG emis­sions due to con­nect­ed devices come from both their pro­duc­tion and use. It is gen­er­al­ly con­sid­ered that half of the ener­gy con­sump­tion con­cerns the pro­duc­tion of objects, the oth­er half their use,” explains Chan­tal Taconet, lec­tur­er in com­put­er sci­ence at Tele­com Sud­Paris. For exam­ple, fig­ures from the ADEME show that over the life­time of a 2kg com­put­er it will gen­er­ate 169kg of CO2 – of which as much as 124kg is from its production.

She points out that a big part of the solu­tion lies in the lifes­pan of our devices, “tak­ing into con­sid­er­a­tion the pro­duc­tion and use of con­nect­ed devices, we can eval­u­ate how long we should use an object or piece of equip­ment – in months or years – to min­imise the envi­ron­men­tal foot­print. We are start­ing to mod­el this cal­cu­la­tion by inte­grat­ing all the para­me­ters.” She cites the exam­ple of a con­nect­ed ther­mo­stat, “we should con­sid­er the quan­ti­ty of the item to be pro­duced, cost of man­u­fac­tur­ing, cost of use, esti­mat­ed life span, etc. From that, we can eval­u­ate an appro­pri­ate lifes­pan to max­imise on the envi­ron­men­tal benefits.”

Such cal­cu­la­tions could tell us, for instance, based on the num­ber of kilo­me­tres trav­elled per year and accord­ing to the coun­try [CO2 emis­sions of elec­tric­i­ty pro­duc­tion dif­fers accord­ing to the coun­try] how many years an elec­tric car own­er should keep their car to obtain the real ben­e­fits in terms of CO2 com­pared to a ther­mal motor car. At Tele­com Sud­Paris, she teach­es the new gen­er­a­tion of dig­i­tal engi­neers, “we encour­age stu­dents to ask them­selves the right ques­tions when design­ing a new sys­tem; to decide whether or not to pro­duce this new object; whether they can expect gains in an accept­able time­frame; and, if so, how to ensure that the sys­tem con­sumes as lit­tle ener­gy as possible.

Inno­va­tions in data transfer

“Dur­ing their life, con­nect­ed devices pro­duce huge amounts of data traf­fic between these objects and the servers that process the data, whether that be in the cloud or oth­er sys­tems such as Edge or Fog Com­put­ing.” In fact, for con­nect­ed objects, the ques­tion of envi­ron­men­tal effi­cien­cy aris­es quite ear­ly in the devel­op­ment process, because the con­sump­tion of the object itself must be reduced to opti­mise the size and life of its bat­tery.” For exam­ple, researchers are study­ing how to make detec­tors ‘sleep’ and ‘wake up’ so that they only wake up when they have some­thing to emit.

In her research, Chan­tal Taconet’s work goes beyond detec­tors, she inte­grates ener­gy effi­cien­cy issues into the design of new soft­ware. “Per­son­al­ly, I con­duct research on dis­trib­uted sys­tems and the role of soft­ware, or ‘mid­dle­ware’, which enables data exchange between dis­trib­uted appli­ca­tion com­po­nents. My research con­cerns the entire chain of events from detec­tion to down­stream soft­ware that is con­trolled via clouds. We will see the biggest improve­ments in ener­gy con­sump­tion if we reduce trans­mis­sions from the whole chain. As such, a sen­sor only trans­mits when nec­es­sary and clouds fil­ter in such a way that they only trans­mit to appli­ca­tions when it cor­re­sponds to a spe­cif­ic require­ment.” For instance, trans­mis­sion sig­nals are dif­fer­ent depend­ing on whether a wire­less sen­sor is installed on top of the Eif­fel Tow­er to inform peri­od­i­cal­ly weath­er sta­tions or installed in a class­room to mon­i­tor the aver­age temperature.

She also sees a key to the solu­tion as find­ing a way to improve effi­cien­cy of data trans­fer through dis­trib­uted archi­tec­ture.  For exam­ple, she is look­ing at archi­tec­ture inno­va­tions such as cloudlets, or small clouds, which are installed near data sen­sors. “The ques­tion is whether or not it is good – in terms of envi­ron­men­tal impact – to have prox­im­i­ty clouds or not. On the one hand, yes, it is good, because it reduces the num­ber of inter­me­di­aries for the trans­mis­sion of data between pro­duc­ers and con­sumers. That said, we don’t know where the pro­duc­ers and con­sumers of this data are locat­ed. So, you need routers and soft­ware servers that dis­trib­ute the data to those who will use it. On the oth­er hand, it may be bet­ter to use cen­tral servers and thus lim­it the num­ber of devices.” 5G is anoth­er area that illus­trates the kind of prob­lems the dig­i­tal sec­tor will need to solve. “For the same amount of data trans­ferred, 5G is cheap­er on the ter­mi­nal side. But it over­laps with exist­ing tech­nolo­gies. In fact, 5G mul­ti­plies equip­ment and anten­nas. And increased through­put always means increased usage.” Yet, over­all, she con­cludes that to reduce ener­gy con­sump­tion and green­house gas emis­sions, “we need to act by reduc­ing the num­ber of devices in use and on the pro­duc­tion of new objects. This is the nerve of the war!”

Turn off your box

Advice for users of oth­er types of dig­i­tal devices (not nec­es­sar­i­ly con­nect­ed objects) includes switch­ing them com­plete­ly off when not in use. The ADEME, for exam­ple, in their report state that “the total con­sump­tion [of an internet/TV box] over a year is between 150 and 300kWh: as much as a large refrig­er­a­tor!” Also point­ing out that “43% of peo­ple nev­er switch off their box and 41% only switch it off when they are away for a long time.” Hence, from the user’s point of view, there are sim­ple steps that could help reduce envi­ron­men­tal impact. In a report by Green­IT, they also sug­gest con­sol­i­dat­ing con­nect­ed devices into one, to improve over­all efficiency.


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