Study of the use of biogas as an energy vector for microgrids

Renewable and Sus ainable Ene gy Re iews 200 (2024) 114574 A ailable online 22 May 2024 1364-0321/© 2024 The Au ho s. Published by Else ie L d. This is an open access a icle unde he CC BY-NC license (h p://c ea i ecommons.o g/licenses/by- nc/4.0/). S udy o he use o biogas as an ene gy ec o o mic og ids Valen yna Loboichenko a , b , Al edo I anzo a , c , Manuel Casado-Manzano a , Se gio J. Na as a , * , F.J. Pino a , Felipe Rosa a , c a Dp o. de Ingenie ía Ene g´ e ica, Escuela T´ ecnica Supe io de Ingenie ía, Uni e sidad de Se illa, Camino de los Descub imien os s/n, Se illa, 41092, Spain b Depa men o Ci il Secu i y, Lu sk Na ional Technical Uni e si y, L i ska S ee , 75, Lu sk, 43018, Uk aine c ENGREEN - Labo a o y o Enginee ing o Ene gy and En i onmen al Sus ainabili y, Uni e sidad de Se illa, Spain ARTICLE INFO Keywo ds: mic og id Biogas Renewable ene gy Powe Capaci y Bio eac o ABSTRACT The e iew p esen s he cu en s a e o he issue abou he s uc u al ea u es o mic og ids as po en ial s uc u al elemen s o ene gy ne wo ks. By analyzing li e a u e da a, mic og ids inco po a ing biogas we e s udied in mo e de ail. I is no ed ha modeling me hods and so wa e compu ing ools a e ac i ely used o ob ain op imal mic og id s uc u es. Va ious op ions o using biomass in mic og ids a e shown, me hods o in eg a ing biogas plan s in o mic og ids and ea u es o hei ope a ion a e p esen ed. The ole o indi idual componen s o a mic og ids inco po a ing biogas has been s udied, heo e ical models and ea u es o he con e sion o biogas in o mic og ids ha e been discussed in de ail. I is no ed ha mic og ids wi h a biogas p oduc ion capaci y o up o 5 MWh/day a e mainly conside ed, and he con ibu ion o biogas in mic og ids a ies in he ange o 1–67 % o he o al p oduc ion capaci y. Implemen ed examples o such mic og ids a e p esen ed and u he p ospec s o hei use a e ou lined. Fea u es o he use o mic og ids inco po a ing biogas, di icul ies o hei p ac ical implemen a ion and he need o u he in-dep h s udy o his issue a e no ed. I is no ed ha he use and implemen a ion o mic og ids inco po a ing biogas will con ibu e o he ene gy inde- pendence o s a es and hei achie emen o sus ainable de elopmen goals. I is expec ed ha he p esen ed e iew will help specialis s mo e clea ly ocus on he p oblema ic issues o mic og ids inco po a ing biogas, and he in o ma ion p esen ed will allow s akeholde s o make in o med decisions abou he choice o powe sys em s uc u e. 1. In oduc ion One o he basic needs o a mode n s a e is he p o ision o a su i- cien amoun o ene gy esou ces necessa y o he smoo h unc ioning o all sec o s o he economy. The une en dis ibu ion o ossil esou ces and hei exhaus ibili y, uns able p icing policy o hese esou ces, he de elopmen o new echnologies and indus ies, he de e io a ion o he en i onmen al si ua ion in he wo ld - all hese ac o s con ibu e o he sea ch o new ene gy sou ces. Signi ican esul s in he de elopmen o he use o sola , wind, wa e , geo he mal ene gy, idal ene gy, and o he enewable ene gy sou ces ha e led o he nex quali a i ely new s age in he ene gy sec o - hei join use [1]. The need o egula e he gene a ion, con e sion and ansmission o ene gy in sys ems wi h se e al ene gy sou ces con ibu ed o he eme gence o a new s uc u e in he ope a ion o ene gy sys ems - he so- called “mic og ids”. Acco ding o he de ini ion o he In e na ional Elec o echnical Commission [2] “mic og id - g oup o in e connec ed loads and dis ibu ed ene gy esou ces wi h de ined elec ical bound- a ies o ming a local elec ic powe sys em a dis ibu ion ol age le els, ha ac s as a single con ollable en i y and is able o ope a e in ei he g id-connec ed o island mode". The modula design o mic og ids, he abili y o egula e ene gy p oduc ion/ene gy consump ion/ene gy s o age, minimiza ion o en- e gy anspo a ion cos s and p oximi y o he end consume made hem in demand, i s o all, o emo e, ag icul u al a eas [3]. A he same ime, hey can be a way o ensu e ene gy au onomy o indi idual communi ies, a eas and acili ies [4] and e en ually en i e s a es. Unde he in luence o he poli ical ac o on impo ed ene gy esou ces, co ec ly unc ioning mic og ids can ac as an elemen o ensu ing he ene gy, and ul ima ely na ional, secu i y o he coun y. Despi e he de elopmen o he concep o mic og ids, he e is no single unde s anding o he mos op imal s uc u e wi h he necessa y quan i y and composi ion o elemen s. One o he p omising componen s is he use o biogas. The use o biogas in he mic og id concep can ac as an addi ional sou ce o ene gy and educe he dependence o egions and * Co esponding au ho . E-mail add ess: [email p o ec ed] (S.J. Na as). Con en s lis s a ailable a ScienceDi ec Renewable and Sus ainable Ene gy Re iews jou nal homepage: www.else ie .com/loca e/ se h ps://doi.o g/10.1016/j. se .2024.114574 Recei ed 8 Ap il 2023; Recei ed in e ised o m 10 May 2024; Accep ed 14 May 2024 Renewable and Sus ainable Ene gy Re iews 200 (2024) 114574 2 s a es on ossil ene gy sou ces. Reducing ca bon emissions allows hem o accele a e hei p og ess owa ds achie ing sus ainable de elopmen . Howe e , sys em esea ch in his di ec ion in he li e a u e is ep e- sen ed e y limi ed. This e iew helps ill his gap. The s udy is aimed a gi ing an idea o he s uc u al ea u es o mic og ids using biogas, biogas con e sion in hem and he p ospec s o u he de elopmen and implemen a ion o his ype o mic og ids. In his e iew, he c i ical compa a i e analysis o he echnical ca- pabili ies o di e en ypes o mic og id sys ems wi h biogas inco po- a ion was ca ied ou h ough a bibliog aphic examina ion o publica ions a ailable in he Scopus da abase. Calcula ion me hods we e used o es ima e he pa ame e s o he sys ems p oposed in he li e a u e. The main con ibu ions o his s udy a e as ollows. Ene gy sys ems in he o m o mic og ids allow he use o enewable ene gy sou ces and ensu e he ansi ion o s a es and egions o a g een economy. The e- iew poin s ou he ea u es o inco po a ing biogas in o such sys ems wi h a ious combina ions o o he enewable ene gy sou ces. As no - el y, i is no ed ha s uc u es wi h biogas p oduc ion capaci y up o 5 MWh/day a e he mos popula among he conside ed mic og id op- ions. A he same ime, li le-s udied aspec s a e highligh ed and inno a i e u he esea ch p ospec s a e indica ed. A unique con i- bu ion o he pape is he compa a i e analysis o he cu en s a e o mic og ids wi h inco po a ed biogas, including a de ailed compa ison and benchma king based on Key Pe o mance Indica o s (KPIs) and also including economic conside a ions and de ail analysis o physical sys- ems in ope a ion. The in o ma ion p esen ed in he wo k will help specialis s mo e clea ly ocus on p oblema ic issues o mic og ids wi h inco po a ed biogas. Wi h he in o ma ion p esen ed in he e iew, scien is s, poli icians and en ep eneu s can make mo e in o med de- cisions abou choosing he s uc u e o he ene gy sys em a he local, egional o s a e le el. In u n, his will con ibu e o achie ing sus- ainable de elopmen goals on a global scale. The e iew is s uc u ed as ollows. Ini ially, in Sec ion 2, a gene al desc ip ion o mic og ids and mic og ids wi h included biogas was gi en. Fu he , in Sec ion 3, a mo e de ailed analysis o ea u es o biogas ans o ma ion in hese sys ems, including he indi idual s uc- u al elemen s o such mic og ids, is p esen ed, and hen, in Sec ion 4, he exis ing eal samples o mic og ids using biogas a e discussed. In Sec ion 5, u he possible p ospec s o he de elopmen o his di ec- ion a e p esen ed. And, inally, in Sec ion 6, conclusions a e gi en. 2. Mic og ids as a ype o ene gy sys ems wi h a ious ene gy sou ces The de elopmen o he concep o mic og ids con ibu ed o he o ma ion o hei s uc u e, ha dwa e and so wa e, he s udy o ene gy low con ol wi hin his sys em and he s udy o he ea u es o i s in e ac ion wi h o he ene gy sys ems. A sepa a e issue is also he unde s anding abou wha hese ene gy sys ems a e. In pa icula , hey a e p esen ed as a “dis ibu ed ene gy sys em” [5], μ G id [6], hyb id enewable ene gy sys ems [7,8], mul i-ene gy complemen a y sys em [9], in eg a ed ene gy sys ems [10], enewable ene gy based powe sys ems [11], mul i-mic og id powe sys em [12]. Fu he de elopmen and imp o emen o he concep o a mic og id wi h se e al ene gy sou ces has led o i s ans o ma ion in o sma g ids (sma ene gy sys ems), whe e an indispensable elemen o he ne wo k is also an in elligen con ol sys em [13]. As a esul , he need o s udy he con ol hie a chy, he s uc u e o con ol le els and con ol ele- men s in hese mic og ids became ob ious [14]. App oaches o he classi ica ion o mic og ids also a y among di e en au ho s. So, hey can di e in e ms o being included in a common powe g id o au onomy (s and-alone sys em, o -g id sys em, islanded, isola ed), by wo king as DC o AC dis ibu ion ne wo ks o bo h, by he p esence o basic elemen s (sola ba e ies, wind u bines, gene a o s, hyd o u bines, s o age ba e ies, con olle s, uel cells, e c.) [6]. Mic og ids can be conside ed in e ms o hei applicabili y – o buildings, dis ic s [15,16], he p oduc ion o one o mo e ypes o en- e gy [17], as well as loca ion - s a iona y (land) o sea ( o ships) [18]. So wa e ools, op imiza ion me hods used in he analysis o a ious mic og id con igu a ions a y [19,20]. Thus, he mos popula ools o de e mining he op imal size o HERS include HOMER and iHOGA (Hyb id Op imiza ion by Gene ic Algo i hms o sys ems om ew W up o 5 MW powe ), which allow you o simula e he s o age o hyd ogen ene gy, RETSc een (Renewable Ene gy and Ene gy E iciency Technol- ogy Sc een), which akes in o accoun only sola , wind and ba e y en- e gy, TRNSYS, which allows you o simula e he ansien beha io o an in eg a ed sys em, as well as a numbe o o he comme cial and ee pla o ms [21]. A a ie y o p edic i e me hods a e applied, such as a i icial in el- ligence models [8], Uni a ia e s a is ical ime se ies models [ 8] [22], linea p og amming and i e a i e me hods [23], machine lea ning [24, 25] o conside ing eal p ojec s [6,26]. Ano he s age in he de elop- men o managed HRES is he use o hyb id op imiza ion me hods, which ake ad an age o se e al me hods and p o ide a syne gis ic e - ec in sol ing op imiza ion p oblems and op imiza ion me hods based on a i icial in elligence [21]. As can be seen, he ongoing e olu ion o ene gy sys ems p o ides an addi ional unde s anding o he s uc u e o he mic og id and i s indi- idual componen s, a he same ime, despi e signi ican e o s in his di ec ion, a numbe o ques ions emain open. Thei unsa is ac o y legisla i e egula ion can be no ed e en in coun ies ac i ely de eloping al e na i e ene gy [17,27]. The e a e disag eemen s in he na ional legisla ions o coun ies using enewable esou ces [28], he need o economic incen i es o g een ene gy [26], dis ega d o he ole o he poli ical si ua ion [29], he need o an indi idual app oach when de eloping a mic og id s uc u e o a pa icula objec [30], he impac o he business model o he ene gy ma ke , en i onmen al and eco- nomic ac o s on he choice o mic og id s uc u e [31,32]. Economic, poli ical, en i onmen al ac o s, among which one can no e he need o sol e he p oblem o domes ic and ag icul u al o ganic was e, as well as he equi emen o a s able ene gy supply o indi- idual acili ies and a eas, ha e led o he sea ch o op ions o in e- g a ing biogas in o he ope a ion o mic og ids. Biogas can be a po en ial sou ce o ene gy, and many land ills, li es ock a ms, and was ewa e ea men plan s cu en ly use biogas collec ion sys ems o i s u he u iliza ion. I biogas is conside ed as one o he sou ces o enewable ene gy, hen i is impo an o e alua e i s use in he s uc u e o mic og ids. Fo u he de elopmen o he mic og id concep , including using sys ems wi h inco po a ed biogas, i is necessa y o analyze bo h he gene al s a e o he issue and he exis ing gaps in his di ec ion wi h a Abb e ia ions AC al e na ing cu en BG biogas CHP combined hea and powe sys em CCHP combined cooling, hea and powe sys em COE cos o ene gy DC di ec cu en HOMER Hyb id Op imiza ion o Mul iple Ene gy Resou ces NPC ne p esen cos PV pho o ol aics PC p oduc ion capaci y SC s o age capaci y TRNSYS T ansien Sys em Simula ion Tool VRLA s al e egula ed lead–acid V. Loboichenko e al. Renewable and Sus ainable Ene gy Re iews 200 (2024) 114574 3 u he sea ch o ways o sol e hem. Biogas is a p oduc o he anae obic decomposi ion o o ganic was e and is bu ned o p oduce hea , elec ici y and ca bon dioxide [33]. Va ious ypes o eac o s a e used o p oduce biogas, o example, wi h a main ank di ided in o wo chambe s (Indian model); wi h a bio eac o ope a ing on he p inciple o a hyd aulic p ess (Chinese model); co e ed lagoon biodiges e s, up low anae obic sludge blanke eac o [34] and e c. The esou ce and echnical capabili ies o di e en coun ies o he p oduc ion and use o biogas a y g ea ly, despi e i s ole in achie ing sus ainable de elopmen goals. This in oduces addi ional es ic ions on he po en ial applicabili y o mic og ids using biogas in hese coun- ies [35,36]. Socio-economic ac o s [37], he exis ence o a egula ed biowas e ma ke [38], as well as he echnical aining o pe sonnel, also a ec he possibili y o ins alla ion, as well as he long- e m and co ec ope a ion o he equipmen [39]. 2.1. O e all desc ip ion o mic og ids inco po a ing biogas A numbe o mic og ids ha use biogas in hei ope a ions ha e been s udied in his wo k. Technical pa ame e s and ea u es o indi idual mic og ids, hei biogas p oduc ion capaci ies, biogas s o age capaci ies, he a io o hese capaci ies o gene al pa ame e s, as well as he main sou ces o biomass a e p esen ed in Table 1. Table 1 gi es a isual ep esen a ion o he s uc u e and cha ac e is ics o mic og ids inco - po a ing biogas. I p esen s he main ene gy sou ces o he mic og ids unde s udy and hei pa ame e s, and also indica es possible ope a ing modes and he so wa e used. I should be no ed ha mos o he conside ed p ojec s o such mic og ids a e a he s ages o s udying he ea u es o he in e ac ion o indi idual elemen s wi h each o he and es ing his in e ac ion, de eloping a i ual model, o , aking in o accoun he physical and geog aphical loca ion o he objec , using specialized so wa e, condi- ions we e simula ed and he op imal con igu a ion was sea ched. Gi en he conside a ion o a ious op ions o equipmen ha uses he sun, wa e , wind, biogas as a sou ce o al e na i e ene gy, i can be no ed ha , o mos o he op ions conside ed, he simul aneous use o all hese sou ces is no ypical. The mos cha ac e is ic op ion is he p esence o sola PV, wind u bine, ba e y s o age and he use o biogas in he mic og id s uc u e. Al e na i e ene gy sou ces such as wind, wa e , sun, a e cha ac e - ized by he ins abili y o he ene gy p oduced, so he use o biogas is a easonable comp omise o s abilize he ene gy supplied o co e he needs o he se iced acili y. In u n, his causes he appea ance o uel cell and ba e y s o age in a numbe o cases conside ed. The compli- ca ion o he s uc u e o such mic og ids equi es con e e s [45,46], also i o e s he possibili y o de eloping in elligen solu ions o he op imal ope a ion o such mic og ids [40,60]. As a sou ce o biogas, he au ho s o en conside a ious ypes o o ganic was e o do no men ion wha ac s as a aw ma e ial, ocusing on s udying he ope a ion o he mic og id as a whole. The applicabili y o biogas is also no always oiced, in mos cases i is conside ed as a sou ce o elec ical ene gy, al hough i can also be used o hea ing [50,54]. The amoun o biogas p oduced in he sys em can ange om 72 Nm 3 /day [40] o 650.5 Nm 3 /day [41]. The esul ing biogas is hen used bo h di ec ly o he p oduc ion o elec ical ene gy [40], and o o he pu poses, o example, in cooking [41]. 2.2. The ole o biomass in he ope a ion o mic og ids inco po a ing biogas In addi ion o biogas i sel , biomass is used in mic og ids. In his case, a ious op ions o i s applica ion a e assumed. Biomass is used o p oduce bioelec ici y and bio uels by gasi ica ion, py olysis, di ec combus ion, anae obic diges ion, e men a ion, and chemical eac ions [76]. I is no ed ha wood and wood was e a e p edominan ly bu ned, while animal and human was e a e mo e sui able o p oducing biogas [77]. Thus, in mic og ids biomass can be con e ed in o ene gy using a biomass gasi ie . By incomple ely bu ning biomass in a biomass gasi ie , syn hesis gas is p oduced, which is hen bu ned o powe a gene a o . This equipmen is cheape han sola PV; howe e , he e a e p oblems wi h esin accumula ion and keeping he eeds ock d y. Spa k plug and balloon coil ailu e and ba e y discha ge as no ed in Re . [78] a e common o hese sys ems. A he same ime, he cos o main aining a gasi ie is signi ican ly highe compa ed o sola panels. Thus, i s o al cos is 53 % he gasi ie /PV/ba e y sys em, gi en ha PV p oduces mo e ene gy (786,705 kWh/y) compa ed o he gasi ie (766,500 kWh/y) [79]. When ope a ing up o 10 h/day he powe capaci y o he biomass gasi ie can each o 30 kW. The aw ma e ial can be o es y and ag icul u al was e [41].The e iciency o he gasi ie is 18 % ( o ice s aw gasi ica ion) [79]. Di e en biomass componen s a e used o di e en ene gy p o- duc ion me hods in a mic og id. Thus, in Re . [68], solid was e (com- muni y was e) is used in biomass-based combined hea and powe . Whe eas biogas ob ained om animal-d oppings o ki chen-was es is supplied o he biogas u bine gene a o . The biomass di ec ly used o p oduce biogas is goa and ca le manu e [55]. Human was e, li es ock was e, and ice husks can also be used, as sugges ed in Re . [46], as well as a sepa a e we ac ion o municipal solid was e [80]. Biogas is gene a ed due o he p esence o a e men e . To de e mine he op imal echnical cha ac e is ics o a mic og id, a biomass gene a o emula o can be used. Wo k [44] shows he pe o - mance o a sys em whe e he main componen s a e PV, a geo he mal sou ce, a biomass gene a o and a s o age sys em. I is assumed ha biogas is gene a ed in he biomass gene a o . Some mic og id sys ems in ol e he use o a biomass elec ical gene a ion uni , whe e, depend- ing on he ype o biomass, i is supposed o p oduce biogas ( ood and human was e) o syngas (ag icul u al and o es was es) [58]. These gases a e hen used in he mic og id o gene a e ene gy. I is no ed ha he ene gy po en ial o syngas and biogas gene a o s is compa able - e iciency is 26 % and 27 %, espec i ely. Thei o al es ima ed elec- ici y p oduc ion is 132 kW/day (biogas) and 158 kW/day (syngas). Using he example o calcula ing mic og id pa ame e s o he illage o Sikkim (India, 2631 people), i is shown ha despi e he smalle occu- pied a ea (2.93 m 2 /kW), he capi al cos o he sys em o p oduc ion o syngas is mo e expensi e (107,895,453 $) compa ed o biogas (13.44 m 2 /kW and 59,796 $). I he e a e sepa a e plan s o con e ing biogas and biomass in a mic og id sys em, hei e iciency changes somewha . Thus, when p ocessing he we and d y ac ions o municipal solid was e, espec i ely, in a biogas p oduc ion plan (32 kW) and a biomass gasi ie (64 kW), biogas o elec ici y con e sion e iciency is 33.5 %, while biomass o elec ici y con e sion e iciency is 20 % [80]. 3. Discussion and analysis o mic og ids using biogas The de elopmen o any mic og id assumes he p esence o a eal objec (objec s) o which his g id plans o be applied. This leads o he ac i e use o simula ion and op imiza ion me hods, which make i possible o de e mine he mos app op ia e (economically, en i on- men ally) echnical cha ac e is ics o a mic og id, and, in some cases, o es hem in p ac ice. In his sec ion, om he heo e ical and p ac ical sides, he con i- bu ion o biogas o he ope a ion o he mic og id is conside ed. An analysis o a ious ma hema ical models desc ibing he p oduc ion, s o age, con e sion o u iliza ion o biogas in he mic og id s uc u e is p esen ed. Va ious ways o p ac ical use o biogas in mic og ids a e conside ed. The echnical pa ame e s o o he possible mic og id ele- men s using biogas we e also analyzed, as we e some o hei economic aspec s. V. Loboichenko e al. Renewable and Sus ainable Ene gy Re iews 200 (2024) 114574 4 Table 1 Main desc ip ion and pa ame e s o mic og ids using biogas [40–75]. V. Loboichenko e al. Renewable and Sus ainable Ene gy Re iews 200 (2024) 114574 5 V. Loboichenko e al. Renewable and Sus ainable Ene gy Re iews 200 (2024) 114574 6 V. Loboichenko e al. Renewable and Sus ainable Ene gy Re iews 200 (2024) 114574 7 V. Loboichenko e al. Renewable and Sus ainable Ene gy Re iews 200 (2024) 114574 8 3.1. Biogas con e sion models in mic og ids In a numbe o wo ks p esen ed in Table 1, ma hema ical models o indi idual elemen s o mic og ids a e conside ed. In pa icula , in Re s. [40–43,46,49,51,55,58,61,62,65,69,72,73,75] p oposed di e en models o biogas con e sion. Thus, models o biogas p oduc ion a e conside ed in Re s. [43,62,65,72]. In Re . [43], he au ho s ake in o accoun he modynamic e ec s when o ming he biogas diges ion model. A mul idimensional he mal ne wo k R–C o a ypical unde - g ound cylind ical diges e is p oposed, aking in o accoun he s uc- u e o he diges e and he in luence o ex e nal ac o s (ai , soil). A model o a biogas eac o ha akes in o accoun he e ec o empe a u e on biogas p oduc ion is discussed in Re . [72]. The o al ans e unc ion model om eed was e inpu o me hane p oduc ion was p oposed by Re . [62]. The au ho s p esen in de ail he ma he- ma ical models o he ou s ages o biogas p oduc ion (hyd olysis, acidogenesis, ace ogenesis, me hanogenesis) and hen desc ibe he o al ans e unc ion model. Au ho s [65] calcula ed he equi emen o he minimum amoun o biogas ha mus be p oduced o supply he biogas d i en gene a o . Elec ici y p oduc ion by he biogas d i en gene a o , he pe iod o ope a ion, he olume ic me hane con en o biogas, he calo i ic ene gy con en o he me hane gas om he biogas and he o e all gas o elec ici y con e sion e iciency o he biogas d i en gene a o a e aken in o accoun . Se e al models o biogas s o age ha e been p oposed by he au ho s [40,42,43,46]. Thus [43], ake in o accoun he hyd odynamic in- e ac ions be ween ese oi p essu e and biogas loading/unloading lows, and p opose a hyd odynamic ne wo k model o ake in o accoun biogas p essu e dynamics in s o age. The pape s [40,42,46] p oposed op ions o calcula ing he size o he biodiges e . Howe e , mos o he conside ed wo ks a e cha ac e ized by he s udy o models o biogas u iliza ion [40–42,49,51,55,58,61,62,69,73, 75]. Modeling o biogas plan , which akes in o accoun elec ical powe gene a ed om he biogas plan , is p esen ed in Re s. [40,60]. A model o a biogas u bine gene a o sys em, in which biogas is used o gene a e elec ici y, in he o m o a ans e unc ion, is p esen ed in Re s. [69, 73,75]. A model o a biogas sys em used o gene a e elec ici y in a mic og id, based on he calcula ion o he biogas a ailabili y, was p o- posed by a eam o au ho s in Re s. [41,55]. The biogas i ed in e nal combus ion engine model p esen ed in Re . [49] includes uel con- sump ion unc ions and such es ic i e pa ame e s as gene a o powe limi s, i s ope a ion and idle ime, and he numbe o gene a o s. A ma hema ical model has been p oposed o de e mine he elec ical powe o a biogas powe plan and he ene gy o biogas p oduced om he manu e o a ious animals [51] o o he aw ma e ials [58]. In he wo k [61], he sys em o equa ions desc ibes he s ages o biogas com- bus ion in he p esence o comp essed ai and powe gene a ion using combus ion p oduc s passing h ough a gas u bine. Au ho s [62] modeled a biogas ene gy p oduc ion sys em and p esen ed he o e all ans e unc ion o he biomass ene gy con e sion sys em. 3.2. Biogas con e sion in mic og ids Acco ding o Re . [40] he main equipmen o a biogas plan is an insula ed chambe , a ib a ing sc een, a coa se and ine g inding combine, a diges e (bio eac o ), a loa ing gas ank, a gas cleaning sys em, a pipeline, a gas gene a o , and a con ol panel. The gas o med in he bio eac o is collec ed in a loa ing gas ank and hen sen o he gas cleaning sys em. Mois u e impu i ies and hyd ogen sul ide a e cleaned in he gas cleaning sys em and hen sen o he gas gene a o . The olume o he diges e is 35 cubic me e s wi h a 15 kVA gene a o . The esul ing biogas is supposed o be used o gene a e elec ici y, al hough he au ho s no e he bioene gy po en ial o he sys em wi h he abili y o p oduce 220.17 kWh o he mal ene gy. The same plan is used o gene a e elec ici y om biogas in a biogas powe plan in he wo k o he au ho s [42]. V. Loboichenko e al. Renewable and Sus ainable Ene gy Re iews 200 (2024) 114574 9 The me hane con ained in biogas can ac as a sou ce o he mal en- e gy in he mic og id and be used o hea ing [50]. Combus ion o biogas o p oduce hea and elec ici y is p oposed in Re s. [56,61,72]. Using a solid oxide uel cell, acco ding o he au ho s [53] will imp o e he e - iciency o his p ocess. In [45,46,48,49,51,52,60,62,63,68,75] he conside ed model sys- ems mic og ids in ol e he use o a biogas gene a o o gene a e elec- ical ene gy. Mic og id using biogas no only as a sou ce o elec ical ene gy, bu also o cooking is discussed in Re . [47]. Biogas in a mic og id can be used no only o gene a e elec ici y, bu also o p o- duce hyd ogen [57]. Mesophilic diges ion o biogas in an anae obic 600 m 3 unde g ound cylind ical diges e is conside ed o biogas p oduc ion in Re . [43]. The esul ing biogas is loaded in o a 600 m 3 biogas s o age ank, and hen can be used wi h op imal solu ions o di ec cooking and hea ing o cogene a ion wi h combined cooling hea ing and powe uni [43]. I is possible o ob ain biogas om animal manu e and plan esidues, he esul ing biogas is used o cooking, and he es is used o gene a e elec ici y [41], [55], [67]. I he e is an excess biogas in he sys em, me hane gas (CH 4 ) is spli in o hyd ogen and ca bon a oms h ough se e al p ocesses, and he esul ing hyd ogen is hen s o ed as uel o he uel cell. Biogas is di ec ly p oduced om biodeg adable animal was e and exc emen and used o gene a e elec ici y using a biogas u bine gene a o . [69]. Analysis o he quan i a i e da a p esen ed in Table 1 [40,43,48] allows us o speak abou he p edominan ole o biogas as a s o age sys em in a mic og id, ega dless o he o al s o age capaci y o he sys em as shown in Fig. 1(a) and (b). The BG SC alues hemsel es ange om 15 kWh o 184 kWh, a ying mo e han 10 imes depending on he o al SC o he sys em. As can be seen om Fig. 1, he sha e o ene gy in he mic og id p oduced using biogas anges om 12.3 % o 36.06 % [40,41,51,52,58]. Al hough bounda y cases a e also accep able, whe e he con ibu ion o biogas as an ene gy sou ce in he mic og id can a y om 1 % [67] o 66,5 % [61]. A he same ime, he au ho s choose he mos op imal mic og id model o he gi en condi ions, as shown in Fig. 2. Fu he , indi idual elemen s o mic og ids using biogas a e consid- e ed in mo e de ail. The ole o biogas in he ene gy p oduc ion sys em a ies somewha . Wi h o al sys em PC om 1 MWh/day o 1200 MWh/day [40,41,58,66, 67] BG PC can a y in a e y wide ange - om 380 kWh/day o 12000 kWh/day in he s udied mic og ids wha is shown in Fig. 3(a) and (b). I BG PC in he mic og ids discussed in Table 1 is con en ionally di ided in o h ee sub anges – up o 5 MWh/day, up o 100 MWh/day, up o 500 MWh/day as shown in Fig. 4, hen i can be no ed ha in 67 % o hese mic og ids BG PC does no exceed 5 MWh/day. Since he de elopmen o a mic og id akes in o accoun he indi idual cha ac- e is ics o he acili y, i can be no ed ha he mos popula a e mic og id s uc u es wi h a biogas p oduc ion capaci y o up o 5 MWh/ day. 3.3. Mos common s uc u al elemen s o a mic og id using biogas Sola panels a e a widely used ene gy sou ce oday. They occupy one o he key places in he mic og id s uc u e. Thei o al powe is de e - mined by he design o he mic og id and can ake alues om 500 W [62] up o 10 MW [81], and he op imal powe , as well as he numbe o ba e ies, is selec ed by simula ion me hods, aking in o accoun he needs o he acili y. Рho o ol aic modules a e combined in o a sola PV sys em. In his case, he sola adia ion a ec ing he su ace o he sola PV sys em is con e ed in o elec ici y [41]. In Re . [41] sola PV sys em consis s o se e al PV modules. Modeling a pho o ol aic sys em assumes he use o a single diode model o a pho o ol aic module. I s ope a ion p o ides 13 % o he o al ene gy p oduced by he mic og id. A se o 314.5 MW pa abolic ough sola collec o s is in Re . [64] pa o an in eg a ed biome hane/biome hanol cogene a ion amewo k using biogas as eeds ock. Polyc ys alline ype sola panels wi h a maximum a ed powe o 62.73 W a e o e ed as pa o a 10 MW sola powe plan [51]. An in e e is used o con e he DC powe gene a ed by sola panels in o AC powe . In Re . [44], wel e se ies-connec ed 250 W sola panels om ET-Sola o m a pho o ol aic a ay (2.8 kW), also connec ed o he mic og id ia an in e e . By p e en ing wa e e apo a ion, being mo e ene gy e icien , and imp o ing wa e quali y, loa ing sola panels a e conside ed mo e en i onmen ally iendly. Howe e , his can in- c ease hei cos by 10–40 % compa ed o g ound-moun ed PV in- s alla ions [45]. Ano he basic elemen o mic og ids is he wind u bine. Thei pa- ame e s a e modeled aking in o accoun he wind egime and clima ic ea u es o he a ea, aking in o accoun he heigh o he wind gene a o [40]. They can ha e powe om 1 kW [45] up o 3400 kW [67], p o ide up o 13 % o he o al ene gy p oduced by he mic og id [67]. Al hough i s con ibu ion may no exceed 2.5 % in gene al, i is a bladed u bine connec ed ia an in e e o a mic og id [40]. So, 1 kW HAWT (ho i- zon al axis wind u bine) wind u bine has a o o diame e o 2.8 m, blade numbe - 3, which allows i o ope a e a wind speeds up o 40 m/s [40]. The wa e po en ial o he a ea, as well as he ene gy needs o he acili y, ob iously de e mine he use o a hyd o u bine in he mic og id. In u n, he powe o he hyd o u bine i sel is a ec ed by he a io o p essu e and olume ic low o wa e [41]. The capaci y o hyd o u - bines in mic og ids anges om 40 kW [41] o 300 kW [58]. In each speci ic case, he powe o hyd okine ic u bines and hei numbe de e mine he op imal mic og id con igu a ion. Mic og ids may include uel cells. In a mic og id, hey can ope a e in se e al modes - bo h di ec ly in he uel cell mode and in he elec olyze mode. So, in Re . [48] uni ied egene a i e solid oxide uel cell can be ed by a pu e hyd ogen and a mix u e o biogas (CH 4 and CO 2 ) a di e en a ios, a ying acco ding o he mic og id ope a ing condi- ions, wi h all o hese gases con ained in a unique ank designed o s o e his mix u e. Inclusion o an elec olyse and a uel cell in a mic og id [69] allows o s abilize possible luc ua ions in he ene gy gene a ed by he sys em. So, i excess ene gy is gene a ed in he sys em, hen he elec olyze p oduces hyd ogen and s o es i . In he e en o a powe sho age, he s o ed hyd ogen is used as uel in a uel cell. The p o- duc ion discussed in Re . [64] is an imp o ed sys em o he simul a- neous p oduc ion o biome hane and biome hanol, whe e biome hane is ob ained by cleaning biogas, and he hyd ogen p oduced by elec olysis is used o p oduce biome hanol. An impo an elemen in ensu ing s able ope a ion o mic og ids is he ba e y. The main applica ions a e anadium edox low ba e y, Li- ion ba e y and lead acid ba e y. So, in Re s. [40,42] use he 1 kW/6 kWh anadium edox low ba e y whe eas 12 V VRLA ba e y is used in he mic og id s uc u e in Re . [44]. In Re . [45] subs an ia es he op imal combina ion o a mic og id wi h a second-li e ba e y ene gy s o age sys em based on li hium-ion ba e ies. Li-ion ba e ies a e sug- ges ed in Re . [49] (200 kW) and in Re . [52] (3000 kWh). In addi ion o he basic equipmen lis ed abo e, some echnical el- emen s can also be used in a mic og id. Thus, de ices o con e ing se e al ypes o ene gy can be included in he s uc u e o a mic og id. Namely, an elec ic hea pump, a u nace and an abso p ion chille , which a e used o con ol he ou pu ene gy in he equi ed quan i ies [43]. I he use o ene gy om geo he mal sou ces is expec ed, hen a geo he mal gene a o (2 kW) may be included in he s uc u e o he mic og id. I can be conside ed as a p ima y sou ce o ene gy p o ided ha he geo he mal wa e low is cons an [44]. Some au ho s see a con e e as pa o addi ional equipmen , he powe o which can be 55 kW [46], 300 kW [58], 2700 kW [45], 6834 kW [67], 20,000 kW [52]. Some imes, in o de o educe he dependence o he sys em on enewable ene gy sou ces and inc ease i s eliabili y, he au ho s sepa- a ely include a diesel gene a o [46,55] o biodiesel gene a o [47,68, 69,73,75] in he design o mic og ids. To con e excess ene gy gene - a ed in a mic og id in o hyd ogen, an elec olyze can be sepa a ely in eg a ed in o i s s uc u e [69]. In some mic og ids, he au ho s V. Loboichenko e al.