District heating and cogeneration in the EU-28: Current situation, potential and proposed energy strategy for its generalisation

Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 107 Dis ic hea ing and cogene a ion in he EU-28: Cu en si ua ion, po en ial and p oposed ene gy s a egy o i s gene alisa ion En ique Rosales-Asensio1 {en ique. osa[email p o ec ed]} Da id Bo ge-Diez1,2 {da id.bo [email p o ec ed]} 1Depa men o Elec ic, Elec onic and Con ol Enginee ing, UNED Juan del Rosal, 12 – Ciudad Uni e si a ia. 28040 Mad id - SPAIN Phone +34-913-987-788 Fax +34-913-986-028 2Dp o. de Ing. Eléc ica y de Sis emas y Au omá ica, Uni e sidad de León Campus de Vegazana s/n. Escuela de Ingenie ías. 24071 León T : (+34) 987 29 19 93; Fax: (+34) 987 29 17 90 Recei ed: 2016-05-12; Accep ed: 2016-08-11 Abs ac Yea ly, EU-28 con en ional he mal gene a ing plan s ejec a g ea e amoun o ene gy han wha ul ima ely is u ilised by esiden ial and comme cial loads o hea ing and ho wa e . I his was e hea we e o be used h ough dis ic hea ing ne wo ks, gi en a p e ious ene gy alo isa ion, he e would be a no iceable dec ease in impo ed ossil uels o hea ing. As a consequence, bene i s in he o m o an ene gy e iciency inc ease, an ene gy secu i y imp o emen , and a minimisa ion o emi ed g eenhouse gases would occu . Gi en ha i is no expec ed o hea demand o dec ease signi ican ly in he medium e m, dis ic hea ing ne wo ks show he g ea es po en ial o he de elopmen o cogene a ion. Howe e , o make his happen, some ba ie s ha a e a om being echnological bu a e mos ly ins i u ional and inancial need o be emo ed. The pu pose o his e iew is o p o ide in o ma ion on he po en ial o using was e hea om con en ional he mal powe plan s (subsequen ly con e ed in o cogene a ion plan s) in dis ic hea ing ne wo ks loca ed in he EU-28. Fo his, a p elimina y assessmen is conduc ed in o de o show an es ima e o he cos o adop ing an ene gy s a egy in which dis ic hea ing ne wo ks a e a majo playe o he ene gy mix. F om his assessmen , i is possible o see ha e en hough he ene gy s a egy p oposed in his pape , which is based on a d ama ic inc ease in he join use o dis ic Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 108 hea ing ne wo ks and cogene a ion, is capi al-in ensi e and would equi e an annual in es men o oughly 300 billion eu os, i s adop ion would esul in a educ ion o yea ly uel expenses in he o de o 100 billion eu os and a sho ening o abou 15% o he o al inal ene gy consump ion, which makes i o pa amoun in e es as an enable o he legal basis o he “Secu e, Clean and E icien Ene gy” u u e enac ed by he EU-28 Ho izon 2020. Keywo ds: dis ic hea ing ne wo ks, cogene a ion, ene gy po en ial, EU-28 Nomencla u e and uni s AHDD annual hea demand pe dwelling DCNs dis ic cooling ne wo ks DHNs dis ic hea ing ne wo ks HHW hea ing and ho wa e HPR hea o powe a io LAs local au ho i ies LF load ac o Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 109 1. In oduc ion F om he simpli ied ene gy balances pe o med annually by EUROSTAT (2013 is he las yea o which da a is a ailable), con en ional he mal powe plan s loca ed in he EU-28 was e mo e ene gy in he o m o esidual hea han wha inally esiden ial and comme cial buildings use o hea ing [1,2]. As is clea om (Fig. 1), i his esidual hea could be used p e ious ene gy alo isa ion om cogene a ion in dis ic hea ing ne wo ks, a no iceable dec ease in he amoun o impo ed ossil uels and g eenhouse gases emi ed in o he a mosphe e would occu (in he Theo e ical Backg ound sec ion, addi ional in o ma ion on he ela ion be ween elec ici y and hea in a cogene a ion plan is included), which would esul in economic, en i onmen al, and ene gy secu i y bene i s. Figu e 1. Ene gy balance o he EU membe s a es o he yea 2013 [2] F om (Fig. 1), i is impossible o de e mine how much hea can be used. Many powe plan s ha e o be necessa ily loca ed a om he he mal loads o ci ies (e.g., coal powe plan s a e usually loca ed close o a po o s ock). Howe e , in a u u e scena io, i could be mo e bene icial, om an economic pe spec i e, o place hose plan s in he icini y o he ci ies. As hey a e en i onmen ally iendly hey can be loca ed close o hem. The old plan s should be disman led when hei use ul li e ends. This supposes an addi ional expense o anspo ing coal o ligni e in o de o be able o use was e hea om powe plan s [3]. 0 20 40 60 80 100 To al p ima y ene gy supply To al hea consump ion ( e ia y sec o ) To al hea consump ion ( esiden ial sec o ) EJ Ene gy balance o he EU-28 membe s a es o he yea 2013 Losses in he ene gy ans o ma ion sec o Losses in end use Combus ible enewables and was e Sola /wind/geo he mal/o he Hyd o Nuclea Na u al gas Pe oleum p oduc s Coal and coal p oduc s T anspo a ion Elec ici y Hea Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 110 In (Fig. 2), i can be seen as ano he way o ep esen ing he ene gy balance (which again shows he impo ance o was e hea om powe plan s) [4]. Figu e 2. Powe consump ion o households loca ed in he Eu opean Union depending on he ene gy end-use. Sou ce: Adap ed om [5] As seen in (Fig. 3), abou 80% o he ene gy used in homes has as ul ima e goal o p o ide hea ing and ho wa e ; his means ha , acco ding o (Fig. 2), he e would be po en ially abou 15 000 PJ/yea (4100 TWh) o be sa is ied h ough he was e hea om powe plan s (no e ha his amoun is less han he esidual hea emi ed by powe plan s loca ed in he EU-28, 19 608 PJ/yea ; Fig. 2). Finally, (Fig. 4) shows he ene gy sha e o each dis ic hea ing esou ce —i is possible o see ha , o he EU, mos o he hea comes om was e hea om powe plan s. 0% 10% 20% 30% 40% 50% 60% 70% 80% Hea ing Wa e hea ing Cooking Elec ici y (ligh ing and whi e goods) Sha e Yea Ene gy consump ion in dwellings by end uses 1990 2012 Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 111 (a) (b) Figu e 3. Ene gy sha e (a) and gene a ion o each dis ic hea ing sou ce (b) in he EU- 28 [10] 0% 20% 40% 60% 80% 100% 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Sha e Hea sou ces used in EU dis ic hea ing ne wo ks Fossil uels, di ec use Renewables, di ec use (biomass and was e hea ) Recycled hea , enewable cogene a ion (biomass and was e hea ) Recycled hea , ossil cogene a ion and indus ies 0 500 1000 1500 2000 2500 3000 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 PJ/yea Ene gy sou ces in EU dis ic hea ing ne wo ks Fossil uels (di ec use) Renewables (bio uels, geo he mal, sola , e c.) + was e (di ec use) Was e hea eco e ed / ecycled om biomass and was e (indi ec use) Was e hea eco e ed/ ecycled Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 112 Despi e hese da a, i should be no ed ha , due o he lack o ene gy ma ching h oughou he yea , as well as o he p oblem o he ejec hea empe a u e (cogene a ion can conduc an ene gy alo isa ion o his low- empe a u e hea in an economical way), no all o hese he mal loads can be sa is ied by he was e hea om he mal powe plan s. This makes necessa y o es ima e hei eal po en ial including assump ions as close as possible o he eali y and o conduc an economic and en i onmen al assessmen ( educ ion o g eenhouse gas emissions) ha includes a gene alised sp ead o dis ic hea ing ne wo ks using as an ene gy sou ce was e hea om con en ional he mal powe plan s in he EU-28, which will be conduc ed in his e iew. The objec i e o his pape is o p opose an ene gy s a egy which enables, h ough he gene alisa ion o he join use o dis ic hea ing ne wo ks and cogene a ion in he EU-28, he ul illmen o he legal basis o he H2020 “Secu e, Clean, and E icien Ene gy” goals in a easible, eliable, economically ad an ageous, and sus ainable way. The me hod p oposed he e uses a sys ema ic and easy app oach (nei he s ong ma hema ical skills no non-widely used so wa e is equi ed) and manages o p opose an ene gy s a egy o such a big egion as EU-28 based mos ly on a ailable public da a (wi h he excep ion o he plan da a ob ained h ough he GESTIS da abase by using he A cGIS so wa e). This is o g ea impo ance as o he me hods a e ne wo k-o ien ed (dis ic hea ing ne wo k); lack om massi e su ace applicabili y [6], being inadequa e o such a big a ea as Eu ope; a e limi ed o indus ial si es [7]; o p esen assessmen s which need a dis ic hea ing ne wo k axonomy [8], in o ma ion no a ailable in he as majo i y o he cases. As a consequence, hey a e no use ul o he pu poses o his pape . To ou knowledge, he e is no a single scien i ic pape which speci ically add esses he po en ial o he join use o he mal powe plan ejec hea in o dis ic hea ing ne wo ks ac oss he Eu opean Union. Thus, we o e new insigh s in o his ma e . In he i s sec ion, he i s app oach o he ene gy balance o he EU-28 membe s a es is desc ibed, and he po en ial o using he was e hea om con en ional he mal powe plan s is discussed. Meanwhile, he second sec ion will p esen he me hodology used o de elop he e iew conduc ed he e. In he hi d sec ion, s udies e alua ing he po en ial o using join ly dis ic hea ing ne wo ks and cogene a ion o di e en egions will be p esen ed. In his sec ion, in o ma ion ega ding p ices o dis ic hea ing ne wo ks, anspo , dis ibu ion, and he mal s o age, as well as a p esen a ion o he case o Copenhagen as an example o a ci y ha has succeeded in combining elec ici y, dis ic hea ing ne wo ks, na u al gas, and was e managemen p ope ly is p esen ed. In he ou h sec ion, di e en scena ios on he e olu ion o dis ic hea ing ne wo ks and he es ima ed economically easible con en ional he mal powe plan con e sion po en ial will be p esen ed. The i h sec ion is ese ed o he discussion, and he six h sec ion p esen s he conclusion, in which he implica ions ( es ic ions and bene i s) ha Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 113 he gene alisa ion o he join use o cogene a ion and dis ic hea ing ne wo ks in he EU- 28 will be shown. 2. Ma e ial and Me hods To gi e documen a y s eng h o his e iew, i was necessa y in he i s ins ance o consul mo e han 100 scien i ic publica ions and/o g ay li e a u e in he ield o cogene a ion and dis ic hea ing ne wo ks. While no absolu e, i is a ep esen a i e sample o he s a e o he a o he subjec unde s udy. Subsequen ly, and o de e mine he deg ee o ma ching be ween he abo e publica ions and he pe cep ion o expe s om a ious membe s o he EU-28, a o al o nine expe s om se en coun ies o he Eu opean Union (see sec ion "Acknowledgemen s") we e consul ed h ough ques ionnai es, email co espondence and/o elephone con e sa ions. Once he scien i ic/g ay li e a u e and he expe s we e consul ed, he hi d s ep aken was o use a ious da abases o es ima e he po en ial o he join u ilisa ion o dis ic hea ing ne wo ks and cogene a ion. Among hese da abases, he mos no able we e EUROSTAT, GESTIS da abase based on Pla s, and The Eu opean Pollu an Release and T ans e Regis e (Eu opean En i onmen Agency). The la e was essen ial o selec ing hose con en ional ones po en ially con e ible in an economical way. The ou h s ep aken was o in oduce some es ic ions on he ype o plan and he dis ance om i o he he mal load (nea es own). To es ima e he cos ela ed o he hea demand, membe s a es o he EU-28 we e i s ly di ided in o zones, wi h he coun ies o cen al and sou he n Eu ope assigned a cos on ene gy demand di e en om he one used only o he coun ies o sou he n Eu ope. This disc imina ion is based on he ac ha , ob iously, he cos s o p o iding hea o he he mal loads dec ease as demand inc eases. Finally, and in o de o know he cos o p o iding hea h ough dis ic hea ing ne wo ks o di e en ypical clima ic zones o he EU-28, [11] was consul ed, which cons i u es a suppo ing ea u e o he e iew p esen ed he e. To he hea demand o each consump ion loca ed in No he n and Cen al Eu ope, a alue o 2000 GWh/yea was assigned, ha ing been es ablished he dis ance om he hea load a 75 km. Meanwhile, o hose loads loca ed in he Sou he n Eu opean coun ies, a ype alue o 750 GWh/yea o hea and 400 GWh/yea o cooling was es ablished, being he dis ance in his case also 75 km. No e ha hese condi ions a e much mo e es ic i e han hose desc ibed in [11]; we ha e p oceeded in his way because such cases, al hough based on eal plan s, ha e be e cha ac e is ics o he con e sion o cogene a ion plan s han hose ha would be conside ed as “ ypical”. Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 114 Due o he ac ha DHNs and DCNs lack a symme ical end-use pu pose (DHNs a e usually aimed a a eas whe e he e a e esiden ial buildings wi hin a ci y, while DCNs end o be ocused only on he cen al a eas o he ci ies) and i s p oximi y- o-load equi emen , i is no possible o dis ibu e cold app op ia ely om an economic pe spec i e. Dis ic cooling is based on a di e ence o empe a u es much smalle han dis ic hea ing; see in Theo e ical Backg ound sec ion o addi ional in o ma ion on he dis ibu ion o hea and cold in mode n hea ing/cooling sys ems) [12]. I would be imp ac ical o ansmi he cold a a dis ance o 75 km, so o he coun ies o Sou he n Eu ope, i has been supposed he use o abso p ion hea uni s ha use he hea om dis ic hea ing ne wo ks o cooling, no being, he e o e, necessa y o use pipes o anspo ing cold a a la ge scale. Some es ic ions ha e been imposed, e.g. only hose he mal powe plan s wi h a a ed powe o o e 300 MW loca ed wi hin 75 km o u ban cen e s o mo e han 100 000 inhabi an s a e conside ed as alid o con e sion, and some da a such as he ollowing was ound ou :  o al ins alled capaci y o he mal powe plan s using ossil uels  o al ins alled capaci y o cogene a ion  CHP gene a ion pe cen age  CHP maximum ins allable capaci y om he mal plan s F om his da a, a easible CHP capaci y ha would comply wi h he a o emen ioned es ic ions is ob ained and p esen ed in he Resul s sec ion. F om hese easible con e ible he mal powe plan s and om da a ob ained om he li e a u e, usable hea , he in es men needed, and uel sa ings a e ob ained and shown in he Resul s sec ion. A summa y o e e y s age o s udy and i s ela ionship wi h he Resul s sec ion would be as ollows: 1) Scien i ic publica ons and/o g ay li e a u e e iew. 2) Expe s in he ield o cogene a ion and dis ic hea ing ne wo ks consul a ion. 3) Da abases (EUROSTAT, GESTIS, and The Eu opean Pollu an Release and T ans e Regis e ) consul a ion.  The ob ainmen o con en ional he mal combus ion capaci y, CHP elec ical capaci y, sha e o CHP elec ici y p oduc ion, elec ici y gene a ion om gene a ion plan s, hea gene a ion om CHP plan s, inal o al ene gy consump ion, o al dis ic hea ing ne wo k sales, and pe cen age o ci izens se ed by dis ic hea ing, is immedia e om EUROSTAT da abases.  The me hodology o assemble he da a ob ained om GESTIS and EPRTR was as ollows: a. Plan da a: GESTIS da abase based on Pla s Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 115 i. This da a was accessed h ough he GESTIS da abase using he A cGIS so wa e. b. Plan coo dina es: EPER/ E-PRTR da abase i. I can be accessed h ough he Eu opean Pollu an Release and T ans e Regis e websi e. Then ollowing s eps we e unde aken “Sea ch he egis e ”> “Facili y le el”> “Coun y”> “EU27”> “Region”> “All egions”> “Yea ”> “2013”> “Indus ial ac i i y”> “Ene gy sec o s” > “The mal powe s a ions and o he combus ion indus ies” > “No sub-ac i i ies” c. Ci y coo dina es: Google Ea h i. No desc ip ion needed 4) Calcula ion o maximum con e sion o CHP by using o al con en ional he mal combus ion capaci y and CHP elec ical capaci y; hea o powe a io by using hea gene a ion om CHP plan s and elec ici y gene a ion om CHP plan s; and maximum annual addi ional hea ou pu by using he maximum con e sion o CHP calcula ed, he hea o powe a io, and supposing a load ac o o 0.6. 5) Res ic ions on he ype o plan (only con en ional he mal plan s wi h a a ed powe o o e 300 MW a e o be conside ed), dis ance ( he mal plan s shall be loca ed a a dis ance below o 75 km o u ban cen e s), popula ion o u ban cen e s (highe o 100 000 inhabi an s) and hea demand in No he n and Cen al Eu ope (2000 GWh/yea ) and hea and cooling demand in Sou he n Eu ope ( espec i ely 750 GWh/yea and 400 GWh/yea ) a e applied. 6) Calcula ion o DHNs easible po en ial by using he maximum annual addi ional hea and he ac ha , a e he es ic ions imposed in 5), abou 50% o he ins alled capaci y o all con en ional he mal powe plan s comply wi h hose es ic ions; calcula ion o con e sion and dis ic hea ing cos s by classi ying coun ies in o Regions (No h e n and Cen al Eu ope and Sou he n Eu ope) and aking in o accoun hea ing (and cooling) cos s in hose egions. 7) Once DHNs' easible po en ial is achie ed and yea ly sa ings in uel a e known, he cos o na u al gas o domes ic consump ion is de e mined, and he usual uel consump ion pe uni o hea supplied o boile s and cogene a ion plan s ( o bo h cases sepa a ely) a e assumed. Th ough he cos di e ence be ween he wo echnologies, uel sa ings a e ob ained. 8) Finally, he esul s om p e ious s eps (1 o 7) a e analysed, and an ene gy s a egy o he gene alisa ion o dis ic hea ing ne wo ks and cogene a ion is p oposed, achie ing, consequen ly, he objec i es o he esea ch. Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 122 3.3 La ge scale hea anspo echnology Hea ansmission expenses h ough la ge-diame e pipes (e en wi h dis ances being conside able) is low [22-25]. As an example, [22] shows ha he cos o ansmi ing 2 GW o hea h ough la ge-diame e pipes a a dis ance o abou 140 km would be abou 0.25 €/kWh, his being due o he ac ha he abili y o anspo hea h ough he pipe is p opo ional o he squa e o he diame e , while he cos o he pipe inc eases p opo ionally wi h he diame e [22]. The e o e, he la ge he piping and he demands o use s, he g ea e he hea loss and he cos pe uni o ene gy deli e ed (Table 2). Table 2. Compa ison o he hea anspo cos depending on he diame e and leng h o he pipe [23] DN Flow Capaci y P ice p . km ench P ice p . km p . capaci y P ice p . km p . annual sale Hea loss p . km mm m/s MW m€/km €/km/MW €/km/MWh/yea %/km 100 200 300 400 500 600 700 800 900 1000 1.0 1.5 2.0 2.3 2.6 2.9 3.2 3.5 3.5 3.5 2 13 38 69 125 203 301 431 551 681 0.6 1.1 1.7 2.2 2.8 3.4 3.9 4.3 4.9 5.7 274 000 78 000 45 000 31 300 22 400 16 700 12 600 10 000 9000 8200 68.0 20.0 11.0 7.0 6.0 3.5 3.5 2.5 2.5 2.5 2.96 1.08 0.50 0.28 0.15 0.11 0.09 0.07 0.06 0.05 Supply empe a u e (p e-insula ed pipes) Re u n empe a u e (designed maximum ope a ing empe a u e = 130 ºC) P essu e loss ( a iable low pumps) 120 ºC 60 ºC 10 mm/m An example o la ge-scale hea anspo echnology can be ci ed he case o Aa hus o ha o P ague. Al hough he dis ance om he cogene a ion plan o he cen e o he ci y o Aa hus is only 20 km [26], he o al leng h o he hea anspo ne wo k ises o 130 km [27], ep esen ing he o al leng h o all pipelines ha a e con inuously connec ed. In (Fig. 10), i can be obse ed ha his la ge-scale hea anspo ne wo k is pa o a sys em consis ing o gene a ing plan s (S uds up ae ke ), closed essels in which wa e o o he luid is hea ed o consump ion peaks, and appa a uses o bu ning was e ma e ial (ACA). Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 123 Figu e 10. Hea anspo sys em o Aa hus [28] As o P ague, hea anspo piping om he cogene a ion plan o Melnik ha e a diame e o 1.2 m and a sys em leng h o 63.5 km [29]. As can be seen in (Fig. 11), o co e much o he dis ance be ween Melnik and P ague, pipes a e laid abo e he su ace. Figu e 11. Pipes o anspo ing la ge-scale hea (2xDN 1200) be ween Melnik and P ague [30] Kedelanlaeg Gjelle up Fo b aendingsanlaeg ACA Kedelanlaeg Jens Juuls Vej Halm a me ae k Solbje g Kedelanlaeg A hus ae ke DONG Ene gy S uds up ae ke Hea exchange s sys em Pumping plan Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 124 3.4 Hea dis ibu ion in mode n dis ic hea ing sys ems In mode n sys ems, he hea dis ibu ion is almos always conduc ed h ough he use o p e- insula ed pipes ha dis ibu e ho wa e [31] (HWP a e usually bu ied di ec ly in he g ound, so hei ins alla ion is cheap, equi ing no main enance) [32]. Fu he mo e, i is no ewo hy ha o ob ain a highe e iciency ega ding elec ici y, hea empe a u e ex ac ion should be as small as possible, being as consequences ha he hea is cheape in uel cos s and he ca bon dioxide emissions a e lowe [33]. These a e he main easons why he e is a end owa ds he use o wa e a a lowe empe a u e—al hough, in a limi ed numbe o sys ems, such a small empe a u e as 45 ºC–55 ºC may be wo king p ope ly [34], a empe a u e be ween 70 ºC and 80 ºC is a mo e “ easonable” one [35–37]. In some ci cums ances, and e y especially in loca ions wi h la e ain whe e dis ic hea ing sys ems ha e a low- empe a u e design (below 90 ºC) [38,39], a di ec connec ion om he dwelling o he p incipal dis ic hea ing ne wo k can be pe o med [37]. This app oach has he ad an age o he abili y o use lowe empe a u es and p o ide he highes e iciency possible, hus gi ing lowe losses pe uni o hea used. Wi h a di ec connec ion, i is possible o elimina e he cos o any hea exchange [37]. A al e ha educes he p essu e o each consume o p e en om o e p essu e o end-use acili ies is used [37]. Di ec connec ions, he e o e, ha e many ad an ages because i is no necessa y o alloca e any in es men o hea exchange s and i allows a mo e e icien ope a ion o cogene a ion ega ding ene gy gene a ion [37]. 3.5 The mal s o age in accumula o s o dis ic hea ing sys ems Cu en ly, a e y limi ed pe cen age o he EU-28 p oduced elec ici y is s o ed (p edominan ly in e e sible hyd oelec ic powe s a ions) [40,41], so any signi ican inc ease (such as by he use o wind ene gy o hea ing buildings) would be ex emely cos ly [42,43] and would in ol e a conside able inc ease in he capaci y o ansmission and dis ibu ion [44]. The elec ici y s o age h ough isen opic hea pumps is cu en ly he only long- e m elec ici y echnology s o age ha can be used in he elec ical ne wo k in an economical way, ha ing a cos o abou 35 €/kWh [45]. Meanwhile, he he mal s o age is conside ably cheape as he cos a ies in a band ange o 0.1 and 10 €/kWh, in his case no needing any upg ading o he elec ici y g id [46]. The mal s o age allows he cogene a ion plan o gene a e elec ici y whene e and o inc ease sys em lexibili y due o he ac ha he mal s o age hea ou pu change is almos immedia e and ha , unlike backp essu e cogene a ion plan s ha ha e o gene a e hea e en when elec ici y p ice is high, condensing-ex ac ion cogene a ion plan s ha e inc eased lexibili y hanks o he possibili y o gene a ing elec ici y exclusi ely [47,48]. Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 125 In (Fig. 12) and (Fig. 13) a e espec i ely shown he hea s o age di ec ly and indi ec ly connec ed o he dis ic hea ing ne wo k. Figu e 12. The mal s o age di ec ly connec ed o a dis ic hea ing sys em [49] Figu e 13. Accumula o wi h hyd aulic sepa a ion om he dis ic hea ing sys em [49] Re u n wa e Fo wa d wa e Cogene a ion plan Hea accumula o Hea consume s Ne wo k pumps Hea accumula o Hea consume s Expansion essel Cogene a ion plan Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 126 3.6 Fuel used in a iabili y and e iciency Wi h he excep ion o hose buildings wi h a la ge numbe o compu e equipmen and due o clima ological easons, domes ic ai condi ioning, in some pa s o Eu ope, is s ill being conside ed a luxu y (meanwhile hea ing is seen as essen ial). Dis ic cooling sys ems a e simila o dis ic hea ing ne wo ks in he sense ha a luid is dis ibu ed and conduc ed h ough ubings [50]. Howe e , he e a e some majo dis inc ions. Fo example, he e a e di e ences be ween he esiden ial and comme cial sec o s, which o he la e , a e domina ed by dis ic cooling ne wo ks [22]. This si ua ion can be gi en he ollowing ac o s:  Ai condi ioning sys ems a e p o usely used in he se ices sec o , whe eas hey ha e a limi ed pene a ion in dwellings [22].  The size o he dis ic cooling ne wo k is a poin o be conside ed so ha i is iable om an economic pe spec i e [51].  No mally, he e is a e ige a ion densi y need equi emen in o de o be p o i able o use as a dis ic cooling sys em, being compulso y ha he use s a e loca ed close o each o he [52].  Ano he ac o is he limi ed a io ene gy/liquid quan i y in compa ison wi h DHNs [53] because o he lowe empe a u e di e ences. Fo ins ance, in dis ic cooling sys ems, low empe a u e is a ound +5 ºC, and back empe a u e is +15 ºC ( empe a u e di e ence o abou 10 ºC). Meanwhile, in a dis ic hea ing sys em, low empe a u e would be a ound 90 ºC, and back empe a u e is a ound 40 ºC ( he e o e, he e is a empe a u e di e ence o abou 50 ºC) [12,53]. This is he eason why pipes used in dis ic cooling ne wo ks a e no mally highe han hose used in dis ic hea ing ne wo ks and hus ha e a highe cos (Fig. 14). Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 127 Figu e 14. Compa ison be ween he pipe diame e s aking in o accoun he di e ences be ween low and back empe a u es [53] Mos cooling applica ions make use o comp esso s d i en by mo o s [54–57], whe e hei coe icien o pe o mance depends hea ily on he empe a u e di e ence [58] ( he be e he coe icien o pe o mance, he lowe he empe a u e o he hea sink is) [59], as well as he ype o comp esso , he a ing powe o he cooling uni , and whe he wa e o ai is used o ca y ou his ask [56]. Fo i s pa , he abso p ion chille s o he hea pumps ope a e unde a di e en p inciple [60,61]. He e, ins ead o using he mechanical powe om a mo o , hey make use o he hea o d i e he cycle [62-65]. I should be no ed ha he coe icien o pe o mance o his echnology lags behind ha o comp esso s d i en by elec ici y [56,66] and a ies o comme cially a ailable low- empe a u e dis ic cooling sys ems om 0.65 o 1.2 [53] — ha is, a uni o hea a low empe a u e is capable o p o iding be ween 0.65 and 1.2 uni s o low- empe a u e e ige a ion depending p ima ily on he numbe o imes ha he hea en e ing he chille is in e nally used [53]. T adi ionally, and due o he ele a ed empe a u e's u ilisa ion ( hose ha occu wi h low- p essu e s eam) [67], abso p ion chille s lowe he coe icien o pe o mance and he e ige a ing capaci y g ea ly as he inle empe a u e o he hea ing medium dec eases (Fig. 15). This has he impo an e ec ha o a gi en cooling capaci y, he p ice o he de ice can become excessi e (Fig. 15) —ne e heless, hese de ices a e o en in dis ic cooling sys ems [68]. 0 10 20 30 40 50 60 0100 200 300 400 500 600 Tempe a u e di e ence (°C) Pipe diame e (mm) Compa ison be ween diame e s ( < 2.5 m/s) 5 MW 20 MW Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 128 Figu e 15. Cooling capaci y o abso p ion chille s in ela ion o wa e empe a u e [69] In (Fig. 16), i is shown ha o 1000 hou s o ope a ion a ull load, cooling cos s by abso p ion (excluding he cos s o cons uc ing he ne wo ks) a e signi ican ly highe han he cos s incu ed wi h he echnology o e ige a ion h ough comp ession. 32 ºC 31 ºC 29.5 ºC 27 ºC 0 10 20 30 40 50 60 65 70 75 80 85 90 95 100 Cooling capaci y (kW) Hea medium inle empe a u e (ºC) Cooling wa e inle empe a u e Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 129 Figu e 16. Compa ison o e ige a ion cos s h ough comp ession and e ige a ion h ough abso p ion (excluding cons uc ion cos s o he ne wo ks) o powe anging om 300 kW o 500 kW and 1000 hou s o ope a ion a ull load [70] As i is clea om (Fig. 17) and as a as ins alla ion cos s a e conce ned, comp ession e ige a ion is signi ican ly cheape han e ige a ion h ough abso p ion. Howe e , as he ins alled powe inc eases, he di e ences dec ease conside ably. 91 66 161 95 0 50 100 150 200 250 300 abso p ion e ige a ion uni (cen alised) comp ession uni (cen alised) abso p ion e ige a ion uni (decen alised) comp ession uni (decen alised) €/MWh Comp ession e ige a ion and abso p ion e ige a ion cos compa ison Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 130 Figu e 17. Compa ison o he in es men cos o di e en e ige a ion machines [70] 3.7 Fuel used in a iabili y and e iciency No mally, when using cogene a ion powe plan s and sac i icing a uni o elec ici y, i is possible o ob ain abou eigh imes his ene gy as hea (in con as , o example, when using a hea pump, i would only be possible o ge ha amoun mul iplied by h ee) [71– 74]. When a plan s a s ope a ing as a cogene a ion plan and i s elec ici y p oduc ion alls, ano he condensa ion plan which is no ope a ing a maximum ou pu will be esponsible o inc easing he powe in o de o compensa e o his change, hus esul ing in a modi ica ion o uel consump ion [75]. By de ini ion, ma ginal powe plan s a e he ones ha dic a e he p ice in e e y hou o all echnologies [76] and, in his case, combus ible used o gene a e elec ici y will emain cons an [77] and a a cons an e iciency [78]. 3.8 Cogene a ion, dis ic hea ing ne wo ks and sma ci ies: The case o Copenhagen The Eu opean Commission's “Sma Ci ies and Communi ies” ini ia i e has al eady exp essed in he “S a egic Ene gy Technology Plan” (SET-Plan) an in e es in posi ioning a numbe o ci ies a he o e on o comba ing and minimising CO2 emissions [79,80]. 0 200 400 600 800 1000 1200 1400 0100 200 300 400 500 600 0 20000 40000 60000 80000 100000 120000 Speci ic in es men (€/kW) Cold capaci y (kW) In es men (€) In es men cos compa ison In es men abso p ion (linea eg ession) In es men abso p ion (cu e i ing) In es men comp ession Speci ic in es men comp ession In es men comp ession (linea eg ession) Speci ic in es men comp ession (cu e i ing) In es men abso p ion Speci ic in es men abso p ion Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 131 Dis ic hea ing and cooling ne wo ks will be sma e as hey make he elec ic g id sma e [81,82]. Consequen ly, i will be especially impo an ha he hea ing and cooling ha e hea ese oi s [83,84] so ha he elec ic g id eac s quickly o p ice signals and can s abilise i sel when he e a e luc ua ing enewable ene gy sou ces. In Denma k, hea ing ne wo ks a e he backbone o he ene gy sys em, p o iding enough lexibili y o in eg a e enewable ene gies (especially wind) in o he elec ic g id in a sa e way [85]. One o he objec i es o he EU-28 ega ding ene gy is p ecisely o make hese sma ci ies adop he Danish ene gy s a egy [86,87]. Renewable ene gy can gene a e elec ici y when p ices in he elec ici y ma ke a e high, and e en hough i con inues o p oduce elec ici y a nigh when demand is low, he s o ed hea may co e peak consump ion ha occu s du ing he mo ning. Wi h espec o he loads o hea ing/cooling, dis ic hea ing ne wo ks and in elligen cooling con ibu e o smoo hing hea ing and cooling peak demand, he eby educing peak p oduc ion [88]. Undoub edly, Copenhagen is he wo ld egion ha mo e has managed o in eg a e elec ici y, dis ic hea ing ne wo ks, na u al gas, and was e managemen . Among i s highligh s may be men ioned he ollowing:  98% o he popula ion o Copenhagen is, in hose a eas whe e his in as uc u e is p esen , connec ed o dis ic hea ing ne wo ks [89].  LAs ha e de eloped hea ing plans o he en i e egion, di iding he a eas by op imal echnologies, aking in o accoun economic c i e ia es ablished a a na ional le el by he Ene gy Au ho i y [90–92].  Municipali ies ha e c ea ed companies wi h a municipal pa icipa ion (CTR and VEKS) o de elop he hea anspo sys em, while companies en i ely belonging o he municipali y a e in cha ge o dis ibu ing his hea .  Fo i s pa , he was e managemen company (Ves o b ænding) is in cha ge, apa om he ecycling, o ea ing he was e p oduced by 20 municipali ies [93] o an op imum le el o in oduce cogene a ion in la ge incine a ion plan s o ensu e ha all he ma e ial ha canno be ecycled is used as ene gy. In Denma k, he p o iding o he se ice o dis ic hea ing depends on companies ha a e hemsel es local monopolies, and ha ypically ha e he necessa y in as uc u e o he gene a ion, supply and sale o hea o he end use [94]. In con as o he companies supplying gas and elec ici y, o hese local monopolies, any bene i om he sale o hea will no be pe mi ed o be ob ained [94]. This means ha only he necessa y cos s o cons uc ion, ope a ion, and main enance o dis ic hea ing ne wo ks can inally be included in he ees [95]. Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 138 Table 5. Analysis o he echnical po en ial o dis ic hea ing ne wo ks. Sou ce: Adap ed om [2,11,102,103] A B C D E F G Final o al ene gy consump ion [2] (PJ) To al dis ic hea ing ne wo ks sales [102] (PJ) Pe cen age o ci izens se ed by dis ic hea ing [102,103] Maximum annual addi ional hea (PJ) DHNs easible po en ial (PJ) Region Con e sion cos + DHNs cos [11] (annual cos o in es men in millia ds o €) 2013 2013 2013 Vision Vision Vision AT – Aus ia 1170.2 80.7 24% 111.6 55.8 N–C 2.4 BE – Belgium 1457.1 21.0 3% 60.1 30.1 N–C 1.4 BG – Bulga ia 367.2 18.0 18% 193.0 96.5 N–C 4.2 CY – Cyp us 67.6 0.0 0% 30.2 15.1 S 1.0 CZ – Czech Republic 1000.0 89.4 38% 312.5 156.3 N–C 6.8 DE – Ge many 9096.0 254.8 12% 2393.6 1196.8 N–C 52.6 DK – Denma k 594.3 105.5 63% 57.6 28.8 N–C 1.4 EE – Es onia 120.2 23.0 62% 115.2 57.6 N–C 2.6 ES – Spain 3397.0 0.0 0% 1733.0 866.5 S 52 FI – Finland 1030.6 114.2 50% 115.2 57.6 N–C 2.6 FR – F ance 6366.3 96.1 7% 993.2 496.6 N–C 20.2 GR – G eece 642.2 1.0 0% 286.6 143.3 S 8.6 HU – Hunga y 628.8 31.0 15% 150.8 75.4 N–C 3.4 HR – C oa ia 243.4 9.7 10% 41.8 20.9 N–C 1.0 IE – I eland 449.6 0.1 0% 183.6 91.8 N–C 4.0 IT – I aly 4969.6 33.1 6% 1907.3 953.7 S 57.2 LT – Li huania 198.3 27.1 57% 75.6 37.8 N–C 1.6 LU – Luxembou g 172.9 2.0 6% 0.0 0.0 N–C 0.0 LV – La ia 161.4 21.5 65% 5.0 2.5 N–C 0.2 MT – Mal a 21.0 0.0 0% 11.5 5.8 S 0.4 Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 139 NL – Ne he lands 2141.8 26.1 4% 323.3 161.7 N–C 7.2 PL – Poland 2655.0 248.7 53% 1016.7 508.4 N–C 22.4 PT – Po ugal 663.5 9.0 2% 245.9 123.0 S 7.4 RO – Romania 911.0 54.0 23% 308.9 155.0 N–C 6.8 SE – Sweden 1322.8 176.0 52% 115.2 57.6 N–C 2.6 SI – Slo enia 200.9 7.7 15% 42.5 21.3 N–C 1.0 SK – Slo akia 454.9 82.7 35% 0.0 0.0 N–C 0.0 UK – Uni ed Kingdom 5712.2 41.5 2% 1998.0 999.0 N–C 44.0 EU–28 46 214.5 1573.9 11.8% 12827.9 6414.9 315.0 Finally, he cos s ela ed o he con e sion o con en ional he mal powe plan s in o cogene a ion plan s and he in es men equi ed o he expansion o he dis ic hea ing ne wo ks a e es ima ed in column G (Table 5). Expansion cos s include cos s ela ing o bo h hea anspo as hose incu ed in he dis ic hea ing ne wo k i sel . I should be no ed ha he cos o ne wo k expansion will a y depending on he egion unde analysis. Loca ions whe e AHDD is high incu smalle expenses ( o dis ic hea ing) han hose o egions wi h a low hea demand, whe e a lowe numbe o buildings will need o be connec ed o he dis ic hea ing ne wo k. Fo hose p ojec s loca ed in no he n and cen al Eu ope, deno ed espec i ely unde he “N-C” ac onym (see column F o Table 5), i has been assumed ha hey incu an annual hea demand cos o 45 €/GJ [8]. The cos s o p o iding hea and cold join ly o hose p ojec s loca ed in sou he n Eu opean coun ies, deno ed by he ac onym “S” (column F o Table 5), we e assumed o be 60 €/GJ [8]. No e, howe e , ha ca ying ou an app op ia e assessmen o he ac ual po en iali y o associa ing cu en he mal gene a ing plan s o DHNs (dis ic hea ing ne wo ks) equi es a de ailed analysis o each pa icula case, in which a ious echno-economic pa ame e s a e aken in o accoun –see [11]. Tha is an ex a ea u e o his pape , as his analysis is beyond he scope o his pape . As can be seen in column C (Table 5), abou 12% o he ci izens o he EU-28 ha e access o dis ic hea ing ne wo ks, wi h signi ican di e ences be ween coun ies. I is possible o ind cases whe e he con ibu ion o dis ic hea ing ne wo ks o hea demand is i ually ze o, as in he case o Spain, and o he s whe e he weigh o dis ic hea ing ne wo ks is high (nea ly 2 ou o 3 Danish ha e access o his echnology). A his o ical o he hea p ice p o ided by he dis ic hea ing ne wo ks, he con ibu ion o cogene a ion o p oduce Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 140 elec ici y, and he pe cen age o ci izens who ha e access o dis ic hea ing ne wo ks is p esen ed in (Fig. 6), (Fig. 7), and (Fig. 8); Theo e ical Backg ound sec ion. I is possible o see ha he leng h o he pipes o anspo ing hea om he he mal powe s a ion loca ed a Wilhelmsha en (757 MW) o he ci y o Oldenbu g is o mo e han 60 km and ha his con e sion would be easible om an economic poin o iew. So i can be assumed conse a i ely ha abou 50% o all he elec ic powe allocable o con en ional he mal powe plan s is loca ed wi hin a easonable dis ance o con e hese plan s in cogene a ion plan s [11]. This pe cen age has been ob ained – om he da abase (E-PTR) [104] – a e imposing as cons ain s ha only will be alid o con e sion o cogene a ion plan s hose con en ional he mal powe plan s wi h a a ed ou pu o o e 300 MW placed a a dis ance o less han 75 km om owns o mo e han 100 000 inhabi an s, which esul s in abou 23% ( his ep esen s a 56% o he ins alled capaci y o his echnology) o all con en ional he mal powe plan s no ye con e ed o cogene a ion plan s placed in he EU-28 (in 2013) o comply wi h hese es ic ions (see Table 6). This is he eason why in his pape i has been se as a goal ha 50% o he he mal load (domes ic and comme cial) o he EU-28 is sa is ied h ough he join use o cogene a ion plan s and dis ic hea ing ne wo ks. Table 6. Con en ional he mal powe plan s (no con e ed o cogene a ion powe plan s) wi h a a ed ou pu o o e 300 MW placed a a dis ance o less han 75 km om owns o mo e han 100 000 inhabi an s. Sou ce: Da abase o E-PTR [104] Numbe o con en ional he mal plan s (uncon e ed) nea u ban cen e s. (dis ance <75 km and P> 300 MW) To al con en ional he mal powe plan s (uncon e ed) nea u ban cen e s. (GWe) To al numbe o con en ional he mal powe plan s 393 246.5 1690 Acco ding o (Table 5), i all po en ially con e ible he mal powe plan s, hose wi h a a ed powe o o e 300 MW loca ed wi hin 75 km o u ban cen e s o mo e han 100 000 inhabi an s, we e con e ed in o cogene a ion plan s and hey would ha e access o dis ic hea ing ne wo ks, abou 6400 PJ o hea could be used, wi h a low ca bon oo p in , i an in es men o some 315 billion eu os will be made. A e ha ing consul ed he da abase [104], i was ound ha in mos coun ies, he limi ing ac o is, a he han lack o hea loads, he a ailabili y o he mal plan s. Howe e , in some loca ions, i was possible o obse e he opposi e, as g oups o he mal powe plan s loca ed ela i ely emo e o a uneconomical dis ances o anspo hea happened. Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 141 To ge a clea e idea o he economic bene i s o in es ing in dis ic hea ing ne wo ks, le us assume ha uel consump ion pe uni o hea supplied is 1.1 in he case o boile s [105], being meanwhile 0.125 in he case o cogene a ion plan s [105]. Assuming ha he cos o na u al gas o domes ic consume s was abou 15 €/GJ o he second hal o 2014 [106], yea ly sa ings o 93.6 billion eu os would be achie ed only in uel o an annual in es men 315 billion eu os. This es ima e is only in ended o gi e con ex abou he ea ed magni udes; in any case, i needs u he e alua ion case by case o debug his ough app oxima ion; see [11]. I should be no ed ha , ob iously, his amoun is in i sel an uppe limi , which is subjec o conside able unce ain y and ha some o he con en ional he mal plan s ha he e ha e been supposed o be con e ible e en ually will no . Howe e , i a g ea e commi men a he Eu opean le el in p omo ing he join use o dis ic hea ing ne wo ks and cogene a ion would be ob ained, in he long e m, i would be possible o app oach he uppe limi as new cogene a ion powe plan s we e buil close o he he mal loads. Ce ainly, he ba ie s ha he join use o cogene a ion and dis ic hea ing aces a e no echnological bu ins i u ional and inancial; see [107] o know hese ba ie s in de ail. 5 Discussion As in mos o he dis ic hea ing ne wo ks o he membe coun ies o he Eu opean Union ha belonged o he o me USSR and in he ea ly s ages as compa ed o he es o he EU, i was common p ac ice o use auxilia y boile s ha only gene a ed hea wi hou he e being a i s a willingness o con e hem in o cogene a ion plan s [108-111]. Commonly, hey used cheap o subsidised hyd oca bons [112] ha had di icul ies in bu ning [113]. Wi h he passage o ime, a numbe o auxilia y boile s om some ci ies we e connec ed o o he he mal gene a ing plan s ha could use hei ejec hea . In P ague, wha eally igge ed he connec ion o he Poříčí II powe plan wi h he associa ed desul u ised emissions o he exis ing dis ic hea ing ne wo k, e en aking in o accoun ha he pipes ca ying s eam and ho wa e should ha e a leng h o abou 40 km each one, was he ealisa ion o he ac ha he e was a need o desul u ise emissions om plan s ha bu ned di y uels [114]. I migh be hough ha he join use o cogene a ion and dis ic hea ing ne wo ks would only be p o i able in he No he n Eu opean s a es due o hei coole clima e and g ea e he mal equi emen s, a he han be consequen ly applicable o he es o he EU-28. Howe e , he ac ha homes in hese coun ies ha e be e insula ion has as a consequence ha he speci ic he mal demands a e lowe (Fig. 20). Mo eo e , i is unlikely ha he he mal loads in buildings will dec ease so ha he join use o cogene a ion and dis ic hea ing ne wo ks becomes non- iable [115]. On he o he hand, usual educ ions o hea losses in buildings a e no as high as expec ed in he i s ins ance ( he use s o see an Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 142 imp o emen in he e iciency o an ene gy se ice ha leads o a educ ion o he ac ual cos o he se ice end o consume mo e, causing he known ebound e ec ) [116]. This e ec , al hough di icul o quan i y (bu eal), migh esul in a dec ease in he mal load educ ions o be ween 10% and 30% [116]. The ision o he no o , a leas , modes changes in hea demand is based on o ecas s conduc ed by each o he membe s a es. As an example, i is p esen ed he case o I eland (Table 7), whe e i is possible o see ha o he pe iod 2008–2020, i is expec ed o inc ease he he mal ene gy consump ion by only a 0.3% [117], e y much in line wi h o he coun ies EU-28. Figu e 20. Use ul ene gy consump ion o hea ing in equi alen kilog ams o oil pe m2 and hea ing days wi h espec o he pe cen age o cen alised hea ing o some EU membe s a es [118] 1 1,5 2 2,5 3 3,5 4 4,5 40% 50% 60% 70% 80% 90% 100% Use ul consump ion pe m2 (koe/m2/dd) % cen al hea ing Use ul ene gy consump ion o hea ing Spain Bulga ia Slo akia Po ugal No way Ne he lands Slo enia Czech Republic La ia Sweden I aly F ance Denma k I eland Poland Aus ia Finland UK Ge many Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 143 Table 7. The mal ene gy consump ion by sec o o I eland (2008-2020) [117] To al inal demand (k oe) G ow h (%) A e age annual g ow h (%) Sec o al sha es (%) End-use 2008 2012 2020 08-20 08- 20 08- 12 12-20 2008 2010 2020 Indus ial 139 148 150 0.6 1.5 0.2 2.5 2.8 2.6 Residen ial 44 43 41 -0.5 -0.5 -0.5 0.8 0.8 0.7 Se ices 15 14 14 -0.5 -1.0 -.02 0.3 0.3 0.2 To al enewable ene gies 198 205 205 3.7 0.3 0.9 0.0 To al consump ion 5502 5209 5718 4.0 0.3 -1.3 1.2 Hea ing om enewable ene gies 3.6 3.9 3.6 Fu he mo e, he e a e se e al easons why i is easie o inc ease gene a ion om enewable sou ces (pa icula ly wind) han om cogene a ion. In he EU-28, wind ene gy (along wi h hyd oelec ic powe ) is he dominan ene gy sou ce om enewable o igins [119,120], being necessa y in his case only ha he p omo e loca es a loca ion and would ob ain he a ious needed pe mi s. Because he e a e usually many loca ions whe e o deploy a p ojec , he e a e high chances ha he same is ca ied ou . By con as , cogene a ion is undoub edly much mo e es ic ed because i ine i ably has o be used in ci ies and indus ies —ob iously, he di icul ies associa ed wi h implemen ing a dis ic hea ing ne wo k o an en i e ci y a e o a di e en o de han hose ound in ob aining pe mission o implemen ing a wind a m. The cogene a ion plan s a e also subjec o mo e es ic ions han hose plan s ha p oduce hea and elec ici y sepa a ely. This is because al hough he elec ici y is cheap and easy o anspo o e long dis ances (in Theo e ical Backg ound sec ion i is possible o ind addi ional in o ma ion conce ning la ge-scale hea anspo a ion), hea needs o be gene a ed locally and can only be anspo ed o much sho e dis ances. Consequen ly, a hea -gene a ing uni will always be connec ed o he end use ; meanwhile, elec ici y will eed o he elec ic g id in gene al. In o he wo ds, he cogene a ion plan will ha e o compe e in he hea ma ke wi h, o example, hea boile s o hea pumps, and in he elec ici y ma ke wi h mo e lexible powe plan s [121]. Despi e hese es ic ions, i is o be emphasised ha a highe CHP and DHNs gene alisa ion (and hei associa ed he mal s o age; see Theo eci al Backg ound sec io) is o i al impo ance in educing o e all ene gy consump ion in he EU-28, which ob iously Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 144 will impac CO2 emissions. This iew has been he one ha has enabled Denma k, along wi h inc eased ene gy equi emen s o buildings, o p e en an inc ease in i s ene gy consump ion o e he las 30 yea s despi e ha ing expe ienced an inc ease o 70% o GDP du ing his pe iod [122]. Li e a u e indings a e ce ainly inconclusi e in wha dis ic hea ing ne wo ks and cogene a ion po en ial a e espec ed a a pan-Eu opean le el. In ac , e en hough some s udies ha e been unde aken o speci ic coun ies o egions, such as Sweden [123], La ia [124], he Bal ic S a es [125], o USA [126], scien i ic li e a u e has no gi en he same a en ion o he po en ial and he economic and en i onmen al bene i s esul ing om he implemen a ion o an ene gy s a egy based on a massi e inc ease o he join use o dis ic hea ing ne wo ks and cogene a ion in he EU-28. As a esul , and due o he a o emen ioned lack o a en ion, a compa ison be ween his pape and o he scien i ic publica ions is, a leas , p oblema ic (in pa icula , and o Sou he n Eu ope coun ies, a en ion gi en has been i ually ze o). Howe e , i is possible o indica e ha one o he main s eng hs o his pape is ha , by using a simple me hodology, i s app oach and pe spec i e p o ide bo h no el esul s o he scien i ic li e a u e and new insigh s o he Eu opean Union as a whole abou he ue po en ial o his unde exploi ed echnology. Pa adoxically, his s eng h o he simple me hodology is a he same ime a sho coming due o inaccu acies in he dis ic hea ing and cogene a ion po en ial assessmen , and u he esea ch on his issue would be in e es ing o e inemen pu poses. Finally, and as ano he esea ch ex ension, i would be in e es ing o e alua e he applicabili y o o he ejec hea om o he ypes o he mal powe plan s such as biomass and nuclea ones o dis ic hea ing pu poses. 6 Conclusions Abou hal o he ins alled elec ic capaci y in he EU-28, om con en ional he mal powe plan s, is loca ed a an app op ia e dis ance o be able o con e hese plan s in o cogene a ion plan s and o use hei was ed hea in dis ic hea ing ne wo ks. Taking in o accoun he maximum pene a ion ha is economically easible, om an annualised in es men in in as uc u es o 315 billion eu os, he cos s, assignable o uel, would be educed by 95 billion eu os pe yea and would sa e abou 6400 PJ o p ima y ene gy. This ep esen s abou 15% o he o al inal ene gy consump ion in he EU-28 in 2013 (46 214.5 PJ). All hese sa ings a e achie ed om a by-p oduc , such as he was e hea om con en ional powe plan s, cu en ly no u ilised in o de o mee any he mal load due o hei low empe a u e (abou 30 °C). I he ene gy ision, p oposed in his pape , we e implemen ed, i would quad uple ( om 12% o 50%) he access o he ci izens o he EU- 28 o he echnology o dis ic hea ing ne wo ks. This es ima e has impo an poli ical implica ions as a gene alisa ion o he join use o cogene a ion plan s o aise he Mul idisciplina y Jou nal o Educa ion, h p://dx.doi.o g/10.4995/muse.2016.6339 Social and Technological Sciences EISSN: 2341-2593 Rosales-Asensio and Bo ge-Diez (2016) h p://polipape s.up .es/index.php/MUSE/ Mul . J. Edu. Soc & Tec. Sci. Vol. 3 Nº 2 (2016): 107-155 | 145 a o emen ioned empe a u e, and dis ic hea ing ne wo ks would en ail some economic, en i onmen al, and ene gy secu i y bene i s ha a e necessa y o he ul illmen o he legal basis o he H2020 Socie al Challenges “Secu e, Clean, and E icien Ene gy” in a sus ainable way. I has been consequen ly jus i ied ha , de ini ely, he ba ie s ha he p oposed new ision ace a e no o a echnological no o an economic na u e bu a e ins i u ional and inancial. I is wo h o ema k he o ecas ha , i a policy, commi ed o he de elopmen o dis ic hea ing ne wo ks and cogene a ion, is ob ained, i would imply ha o e he nex decades mo e and mo e powe plan s will be buil in p oximi y o he mal loads and decommission hose loca ed emo ely. Finally, and as a possible esea ch ex ension, i would be in e es ing o conside ejec hea om o he he mal powe plan s, such as biomass and nuclea ones. E en hough he la e ones should be conside ed cau iously due o hei ypical loca ions (no mally a om hea loads), ejec ed hea om nuclea powe plan s migh ep esen a signi ican inc ease in he join use o CHP and DHNs, as cu en ly hey ep esen abou 30% o he elec ici y p o ided in he EU-28. Acknowledgemen s We a e g a e ul o he expe s con ac ed who ga e us hei suppo , in pa icula and especially o Poul Albe g Øs e gaa d (Aalbo g Uni e si e ), Capezzali Massimiliano (École Poly echnique Fédé ale de Lausanne), Ke in Sa o (Uni e si é de Liège), E win Co nelis (VITO NV), Chia a Wol e (Ambien e I alia), Alexand a Tudo oiu (COGEN Eu ope), Olu Ogunbadejo (Depa men o En i onmen , Food & Ru al A ai s), Aleksand s Zajacs (Riga Technical Uni e si y), and Ca s en Magass (Fo schungszen um Jülich GmbH). Wi hou hei pa icipa ion, his a icle would no ha e been possible. 7 Re e ences [1] Ecohea cool and Eu ohea & Powe . The Eu opean hea ma ke : Final epo . B ussels: Eu ohea & Powe ; 2006. [2] Eu os a . Simpli ied ene gy balances – annual da a. Luxembou g: Eu os a . Accessed a <h p://ec. eu opa.eu/eu os a /en/web/p oduc s-da ase s/-/NRG_100A> on Oc obe 3, 2015. [3] The Connec icu Academy o Science and Enginee ing. 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