Towards sustainable ICT

. While information and communication technologies (ICT) can play a crucial role in tackling issues related to sustainability, and reducing resource consumption in every sector, they also consume huge amounts of energy, and this, combined with the predicted rapid growth of demand for communication services, is expected to make the whole sector more and more energy-hungry in the coming years. The sustainability of ICT itself is also becoming an urgent challenge. Actions can be taken in several directions: i) introducing a massive and pervasive use of renewable energy sources, a step that requires the design of communication services to be revised; ii) enforcing rules and policies that induce the provisioning of sustainable services and promote the adoption of proper attitudes; and iii) involving the users who will become conscious consumers and participate in crowdsourcing projects to monitor consumption and foster energy-aware behaviours.


ICT as a set of enabling technologies
Whe tacig the issue f sustaiabiity ad the severa chaeges assciated with it ifrati ad cuicati techgy (ICT) has aways bee perceived very psitivey Ideed ICT eabes the devepet f ivatis ad sutis that ca reduce the csupti f resurces i a sectrs Severa f the prpsed sutis are siiar i spirit sharig a geera apprach ad havig the use f se techiques i c sesrs r devices t itr ad cect data a cuicati ifrastructure t carry the data t a ctr cetre ad a cetra aageet uit that taes decisi abut pssibe actis fr the ptiisati f the use f resurces We ca csider exapes fr differet sectrs I eergy itrig systes fr buidigs a sesr etwr is used t itr a uber f paraeters teperature huidity ad the presece f pepe A ctr uit perates the cig ad heatig systes i a ptia way i ters f eectricity csupti A secd exape fr a very differet sectr is predictive aiteace fr pwer grids The eectricity distributi etwr is equipped with sesrs that cect data ad ifrati abut the curret wrig cditis f the eeets f the grid as we as the evireta paraeters The data feeds a ctr uit that ears whe critica cditis ight arise ad taes actis ad cutereasures t reduce the ccurrece f faiures r atteuate their ipact by reactig prpty Siiar exapes ca be fud fr ast every sectr fr aufacturig systes t urba biity fr gistics t eergy geerati pats It is estiated that each sectr wi beefit fr ICT ad wi experiece a reducti i eergy csupti f up t 30% 1 Digitaisati aws the substituti f resurce deadig activities with crrespdig ight eversis that reduce the eed t ve gds ad pepe by vig bits a uch ess deadig effrt This is the case i eearig teewrig deateriaisati  The basis f these pssibiities is the icredibe icrease i cputig strage ad trasissi capacity The faus re's aw first fruated i the 1960s ad the updated states that the uber f trasistrs per chip (ie the uber f eeetary uits f ifrati strage ad cputati that ca fit it a sa chip) wi dube every 18 ths We carry tday i the sartphe i ur pcet the cputatia pwer that was eeded t reach the  i the ate 1960s Siiary trasissi capacity has grw fr the rder f the Gbits f cpper techgy t tes f Tbits (1012 bits) usig ptica fibre cabe techgy

ICT sustainability
Whie ICT pays a psitive re i eabig ivatis fr reductis i resurce csupti se studies have recety estiated that the ICT sectr itsef csues huge auts f eectricity ad it is respsibe fr abut 35% f gba eissis 2 As reprted i 2 a segets f ICT ctribute t csupti with a reativey eve share PCs ad itrs ad the cuicati ifrastructure are respsibe fr abut 40% data strage cputig ad aageet fr 23% It is estiated that i the US ae data cetres (thse big aggregatis f strage ad cputig faciities that cect stre ad eabrate data prvide ctets ad cud services) csue 90 bii Wh per year the equivaet f 30 giat pwer pats f re tha 500 W each a aut that crrespds t 3% f the etire eectricity csupti f the cutry 3 Cuicati ifrastructure csupti is diated by the access etwrs which brig cectivity i the ast hp (the scaed "ast ie") t the users Access etwrs cprise a very arge uber f devices that idividuay csue reativey itte but have a arge aggregated tta csupti The csupti f a base stati the fudaeta eeet f the bie access etwr is i the rder f W but it is estiated that there are seve ii sites wrdwide with severa base statis per site Fr a bie etwr peratr the pwer required fr a the base statis ca reach 80% f the peratia cst f the whe etwr This data suggests that actis fr the reducti f these csuptis are eeded i a segets f the ICT sectr Ideed with the exceptis f cases i which devices rey  sa batteries such as wireess sesrs ad terias usuay the desig f ICT techgies has t csidered eergy csupti ad suppy as a reevat diesi i the desig space Eergy was tae fr grated whe ICT sutis were desiged ad the evved ver the years If ICT csupti is staggerig tday the frecast f its grwth is eve re wrrise i 4 fr exape it is estiated that the carb eissi f the ICT sectr cud reach 14% f the tta by 2040 This is due t the expected icrease i the pervasiveess f ICT The wew Cisc predictis 5 ffer the tred f grwth i iteret traffic that is reprted i Figure 1 The data is give i exabyte (1018 byte) per th a huge uber that tripes i y 5 years There are severa reass fr this grwth The first is the ppuarity f high bit rate services that are based  utiedia streas such as iteret teevisi ad vide cas Figure 2 as based  Cisc predictis shws the traffic grwth fr severa services ad the iprtace f vide services is evidet Secdy the uber f users is grwig wrdwide especiay i devepig areas the cpud aua grwth rate f the uber f iteret users is 50% i the iddeEast ad Africa The uber f cected devices w as Iteret f Thigs fr sesrs t achies ad rbts is aready estiated t be three ties the wrd ppuati ad agai grwth is expected t be extreey fast crrespdig t a grwth factr 5 i 10 years as ca be see fr Figure 3 which is based  the data ad predictis f 6  The cbiati f these factrs pushes the depyet f ehaced cuicati ifrastructure the stregtheig f cuicati ad cputig faciities ad terias ad devices with a crrespdig icrease i eectricity csupti ad carb eissis The sustaiabiity f the ICT sectr is becig a urget eed

Directions for action
As previusy discussed the threat t ICT sustaiabiity arises fr the cbiati f the fresee grwth f cuicati ad ifrati services ad the fact that the traditia desig f ICT has t csidered csupti ad eergy suppy as a ey issue i a cases except whe devices have t rey  sa batteries As a csequece a aspects fr the device architecture t the prtcs fr cuicatis t resurce aageet strategies ad the severa echaiss hidde i a cuicati ad ifrati aageet ifrastructure have a sigificat argi f iprveet fr reducig their csupti Beyd the ehaceet f the eectrics that iprve the eergy efficiecy f the idividua devices there are three ai directis that ca be tae whe csiderig the ICT ifrastructure as a whe

Use of renewable energy
Sustaiabiity cas fr ew eergy geerati pricipes that is fr the use reewabe eergy hwever its itrducti i the cuicati ad ifrati ifrastructure f reewabe eergy surces such as sar paes ad wid turbies with their iterittet ature ad variabiity i geerati is t straightfrward at a Ideed it requires a redesig f architectures ad strategies t verce the assupti that a pwer suppy is ctiuus ad guarateed We ca csider a few exapes The scheduig f tass ad activities ag a set f cputig faciities such as a set f servers shud ai t y at perfrace axiisati but as at csupti iiisati ad it shud tae it accut the avaiabiity f eergy ad the eergy efficiecy f the devices Ather exape ivves access etwrs that prvide cectivity t users The itrducti f a iterittet pwer suppy requires that the etwr is capabe f sefrecfigurig s as t adapt t the pssibe uavaiabiity f des due t eergy shrtage Cectivity shud as be prvided y if ecessary ad i prprti t what is actuay eeded s as t reduce eergy waste I additi t sustaiabiity pwer suppy thrugh reewabe surces is as advatageus i tw types f scearis eergig cutries ad eergecy situatis I eergig cutries the dead fr cuicati services typicay grws faster tha the devepet f the pwer distributi ifrastructure etwrs ad ifrati ifrastructure thus perate uder a ureiabe ad disctiuus pwer suppy T guaratee ctiuity f perati the etwr eeets are fte pwered with csty ad putig diese geeratrs This is the case fr the base statis f ceuar etwrs I 7 it is estiated that 1 ii base statis aready perate withut cutig  a reiabe pwer grid ad e third f these base statis are cpetey ffgrid I these scearis reewabe eergy surces are cst effective ateratives I eergig situatis cuicatis beces fudaeta but frequety as uavaiabe because f the uavaiabiity f the pwer grid I these cases etwrs that ca rey  aterative surces ad ca sefsustai are eeded

Policies and rules
There are a uber f actis i ters f picy aig ad reguatis that ay ptetiay be quite effective These actis ai at iducig re sustaiabe attitudes ad adptig techgies that are re parsiius i ters f resurce usage The ICT wrd experieces such fast evuti that picies ad rues fte d t eep pace sustaiabiity hwever requires urget iterveti ad effective actis The use f eectric devices ad i particuar terias such as aptps ad sartphes ivves a extreey fast turver that is t ustified by the techgica evuti but is rather pushed by a extreey prfitabe aret At the sae tie device edfife is t aaged ad ctred as it shud be with harfu effects fr the eviret Reguatis abut device ed f ife ad the prti f re carefu attitudes by users are bth eeded The presece f cpetig cpaies ruig cuicati ifrastructure iduces a waste f resurces The phee is particuary evidet at the periphery f the etwrs Here whie service dead is variabe accrdig t the typica dayight patters that fw hua behaviur the etwrs are ctiuusy ruig at fu capacity ad csuig ast the sae aut f eergy as if they were wrig at fu ad This iefficiecy is utipied by the uber f verappig etwrs crrespdig t differet techgies ad differet peratrs Icetives fr ifrastructure sharig a srt f crsstechgy ad crssperati ptiisati f the use f the ifrastructure wud be very beeficia t reduce these iefficiecies Udesired ad uecessary ifrati deivery i the fr f uctred advertiseets ad spaig cprises a csiderabe fracti f the tta aut f ifrati that is daiy carried by the etwrs Rues ad echaiss t ctr this ight reduce this uecessary ad geeray uwated but csty ifrati deivery

Users in the loop
Users ca effectivey ctribute t aig ICT re sustaiabe by adptig prper behaviurs as csuers f cuicati services but pepe first eed t be aware that there are sustaiabiity issues arud ICT ad that ctrary t ur perceptis cuicati services csue huge auts f resurces The first preiiary acti ivves disseiatig wedge abut ICT sustaiabiity ad prte eergyaware attitudes Users ca iprve sustaiabiity thrugh a uber f behaviurs First they ca chse ess deadig services wheever pssibe There are fte severa aterative services f the sae id f quaity but differet i ters f csupti due t the aut f ifrati that has t be carried ad the distace i the iteret that the ifrati has t cver aig chices with a awareess f these differeces if practiced by a arge uber f users ca have a sigificat aggregated ipact Cscius chices by a arge uber f csuers ight ffer a cpetitive advatage  the aret t sutis that are parsiius i the use f resurces sparig a virtuus circe i which service prviders desig re sustaiabe sutis Crwdsurcig prects cud as be started t itr resurce waste cect data ad warigs abut pssibe critica situatis share suggestis  gd practices ad s 