Chii chinonzi Peaker Plants?

Peaker zvidyarwa zvivakwa zvekugadzira magetsi zvinoshanda chete panguva dzekudiwa kwemagetsi kwakanyanya, inozivikanwa se peak kudiwa. Zvidyarwa izvi zvinowanzo shanda kwemaawa asingasviki 2,000 pagore-dzimwe nguva zvishoma semaawa 250-zvichiita kuti asiyane nemagetsi ebaseload anoramba achishanda.

Iyo mechanics ye peaker plant center pane kukurumidza kupindura kugona. Vazhinji vemazuva ano vanonyanya kushandisa peaks vanoshandisa -maturbines egasi anopisa gasi chaiwo, anoshanda semajeti injini. Kana vafambisi vegridi vaona kudiwa kuri kuwedzera, maturbine aya anogona kutanga kugadzira magetsi mukati memaminitsi mashanu kusvika gumi nemashanu.

Maitiro acho anoshanda nematanho matatu: compressor inokwevera mweya muinjini nekuimanikidza, majekiseni emafuta anosanganisa gasi chaiwo nemhepo yakadzvanywa iyi mumakamuri ekupisa umo tembiricha inodarika 2,000 madhigirii F, uye inokonzeresa yakakwirira-kuyerera kwegasi kutenderedza mablades eturbine anomhanyisa majenareta kugadzira magetsi. Magadzirirwo akareruka aya{{4}ekutenderera anobatsira kukurumidza-kukwanisa kupisa kwemafuta kunotangira pa20% kusvika pa42%, zvichienzaniswa neyakasanganiswa-zvinomera zvinokwanisa kusvika pa60% kushanda zvakanaka asi zvinotora maawa kuti zvibude zvizere.

Grid operators vanotumira peakers zvine hunyanzvi. Mumazuva ese, zvirimwa zvinotakura zvinhu zvakaita senyukireya, marasha, kana-zvivakwa zvegasi zvakasanganiswa zvinopa simba rinoenderana. Asi kana maairconditioner achinetsa grid panguva yemasaisai ekupisa kwechirimo, mahita emagetsi paanowedzera nguva munguva yechando, kana kuti manheru anoda maspikes vanhu vachidzokera kumba vachibatidza midziyo, mapeakers anovhara mukaha uripo pakati pekuwanikwa uye kudiwa kuri kuwedzera.

United States inoshanda ingangoita 999 peaker zvirimwa kubva muna 2021, maererano nehurumende data. Zvishandiso izvi zvinotora chikamu che3.1% chekugadzirwa kwemagetsi pagore asi zvinomiririra 19% yehuwandu hwakagadzirwa-mucherechedzo wakajeka wemaitiro adzo achinja. Vazhinji vanopisa gasi rechisikigo, kunyange zvivakwa zvekare zvichigona kushandisa dhiziri, mafuta emafuta, kana peturu-zvinwiwa zvepetroleum semafuta ekuchengetedza.

Musika wepasi rose wemagetsi wakasvika pamadhora mazana maviri nemakumi matanhatu nemakumi matanhatu nemakumi matanhatu nematanhatu emadhora muna 124.66 uye unofungidzirwa kuti uchakura kusvika pamadhora mazana maviri nemakumi matatu nemakumi matatu nemakumi matatu nemakumi matatu nemakumi matatu nemakumi matatu emadhora, zvichiratidza kukura kwegore negore kwe4.32%. Kukura uku kunopesana netarisiro yekutanga yekuti simba rinodzokororwa raizoderedza kudiwa kwevakakwira. Pane kudaro, kushandiswa kwavo kwakawedzera mumakore mashanu apfuura.

Tsananguro iri mukusawirirana pakati pemapatani ekugadzirazve uye kutenderera kwekuda. Kugadzirwa kwezuva kunokwira zvakanyanya masikati kana vanhu vazhinji vari kubasa, asi kudiwa kwekugara kunokwira pakati pa4 PM na9 PM apo kubuda kwezuva kuri kudzikira. Kugadzira mhepo kunochinja zvisingatarisike zvichienderana nemamiriro ekunze. Mapeakers anozadza aya mapeak, uye fungidziro inoratidza kuti grid yeUS ichada imwe 20 GW yekukwira pamusoro mukati memakore gumi anotevera.

Peaker Plants

Kunzwisisa kana mapeakers achishanda kunoratidza kuti nei vachiramba vachikosha kunyangwe nguva yavo shoma yekumhanya. Nguva dzepamusoro dzinosiyana nemamiriro ekunze uye mwaka. Munzvimbo dzine mwero, maawa emanheru anoona kudiwa kwakanyanya sezvo dzimba dzinoshandisa mwenje, midziyo yemagetsi, uye masisitimu evaraidzo panguva imwe chete. Mamiriro okunze anopisa anowedzera nguva dzemasikati apo zvinhu zvinofefetera zvinosangana pamwe chete-nezvekutengeserana kuchiri kushanda. Mamiriro ekunze anotonhora anokwira mangwanani apo kupisa kwenzvimbo uye maindasitiri anotanga pamwechete.

Aya mapatani haasi kungofanofungidzira zuva nezuva. Zviitiko zvemamiriro ekunze zvakanyanya zvinogadzira spikes ine njodzi yekuda. Dutu remuchando reTexas ra2021 rakaratidza kusagadzikana uku apo magetsi akajairwa akatadza uye kudiwa kwakapfuura huwandu huripo, zvichikonzera kudzimwa kwemagetsi. Vashandisi veGrid vanochengeta mapeakers akagadzirira nguva dzakaoma idzi dzinogona kuitika kashoma pagore asi zvichiunza kutyisidzira kuripo kune kugadzikana kwegridi.

Muenzaniso wehupfumi unoratidza chokwadi ichi. Nekuti mapeakers anoshanda kasingaperi, magetsi aanogadzira anoraira mitengo yepamusoro-kazhinji $150 kusvika $198 per megawatt-awa payakavhurika-yegasi turbines, zvichienzaniswa nemitengo yakaderera yemagetsi ekutanga. Vashandi vePeaker vanowana mari kuburikidza nekutengesa kwesimba panguva yekushanda uye kubhadhara kwesimba kuchengetedza kugadzirira, zvichiita kuti bhizinesi rishande kunyangwe mitengo yakaderera yekushandisa.

Mamiriro ezvakatipoteredza ezvirimwa zvepeaker anopa matambudziko makuru. Kana ichishanda, mapeakers anoburitsa yakanyanya kusvibiswa pachikamu chemagetsi pane mamwe mafossil anomera. EPA data inoratidza kuti nepo peakers' yegore rose sulfur dioxide inoburitswa yaive yakaderera ne96.8% pane vasiri-peakers (nekuda kwekusashanda nguva zhinji), iyo yepakati peaker yakabudisa ka1.6 more sulfur dioxide pa unit yemagetsi anogadzirwa.

Uku kuwedzera kwehuwandu hwekuburitsa kunoitika nekuti vazhinji vepamusoro havana inoshanda yekudzora emission tekinoroji. Midziyo inodiwa pakukwesha zvinosvibisa inowedzera mutengo uye kuomarara izvo zvinoita kushoma kwehupfumi kune zvirimwa zvinoshanda chete mazana mashoma emaawa pagore. Nekuda kweizvozvo, mapeakers anoburitsa maererano nehuwandu hwenitrogen oxides, sulfur dioxide, uye particulate matter-zvinosvibisa zvine chekuita nedambudziko rekufema, nyaya dzemwoyo, uye kukuvara kwetsinga.

Maitiro enzvimbo anowedzera dambudziko rehutano hwehutano. Ongororo yeStatistics neGovernment Accountability Office yakaona kuti nharaunda dzaisagarika dzinogara pedyo nezvirimwa zvakanyanyisa. Nharaunda ine zvikamu makumi manomwe nechimwe kubva muzana munhoroondo yakare inotarisirwa kunge iri padyo ne9% padyo nepamusoro penzvimbo iri pedyo kupfuura nharaunda ine makumi mana muzana kubva muzana. Vanhu vanodarika miriyoni imwe vanogara mukati memamaira matatu ezvimwe zvivakwa zvepamusoro-soro, vakaungana munzvimbo dzemadhorobha umo kuratidzwa kwetsvina kunokanganisa vanhu vari munjodzi vatove nekuremerwa kwezvakatipoteredza.

Bhatiri inotakura lithiumvari kubuda senzira yekutanga kune zvisaririra zvemafuta, zvakanyanya kushandura hupfumi hwesimba repamusoro. Masisitimu ekuchengetedza magetsi ebhatiri anogona kuita grid rimwe chete-kudzikamisa basa sematurbine egasi asi achipa zvakati kuti zvakanaka: nguva yekupindura inoyerwa mumamilliseconds kwete maminetsi, zero pa-nzvimbo inobuda, uye hapana mutengo wemafuta panguva yekushanda.

Kukwikwidzana kwemitengo kwasvika padanho rekupedzisira. YeAustralia Yakachena Energy Council yakawanikwa muna 2021 kuti kuchengetedza kwebhatiri kunogona kudhura makumi matatu muzana pane zvidyarwa zvitsva zvegasi. Ongororo yekuenzanisa mitengo yakasimudzwa inoratidza bhatiri ye-yemaawa mana inosvika $156 pakilowatt-gore maringe ne$234 yeturbine yakavhurika. Tsvagiridzo yeBloombergNEF inoratidza kuti mabhatiri elithium-ayo ave kuchipa pane zvirimwa zvinonyanya kukwira gasi pasi rose, zvine mwero wepasi rose we$132/MWh pa-mabhatiri emaawa mana{13}}zvikero zvichienzaniswa ne$173/MWh yepeakers.

Chaiyo-yakatumirwa pasi rose inoratidza shanduko iyi. New York Power Authority iri kushingaira kutsiva mapeakers egasi nekuchengetedza bhatiri. MuVentura County, California, 142 Tesla Megapacks inopa 100 MW yakatsiva gasi peaker chirimwa. Belgium yakatumira makumi mana eTesla Megapacks (50 MW) kutsiva jenareta returbojet. Pacific Gas & Electric yakagamuchira mvumo ye300 MW yesimba rekuchengetedza kutsiva zvirimwa zvitatu zvakanyanyisa gasi{10}muenzaniso wakakosha kusvika nhasi wemabhatiri anotsiva kugadzira mafuta efossil muUnited States.

Tekinoroji iyi inonyanya kushanda pakugadzirisa dambudziko re "duck curve" mumagetsi ezuva-anorema. Mabhatiri anochaja kana solar generation yadarika zvinodiwa mukati memasikati, obva abuda panguva dzemanheru nguva dzepamusoro apo kubuda kwezuva kunodonha asi kudiwa kuchikwira. Iyi pateni inoenderana neyakajairwa peaker mashandiro emaawa matatu kusvika mana manheru.

Mabhatiri ekuchengetera masisitimu anotarisana nemiganhu yenguva isingaite gasi peakers. Tubhini yegasi ine mafuta ekufambisa inogona kushanda nekusingaperi, ukuwo mabhatiri achipera mushure menguva yaakagadzirirwa kubuda{1}}kazhinji maawa maviri kusvika mana pakushandisa pazvino-pamwero wekuisa. Chisungo ichi chakakosha panguva yezviitiko zvakawedzerwa kana nguva yakawanda-yemazuva mazhinji emamiriro ekunze.

Zvakadaro, mitemo yemusika iri kushanduka kuti ienderane-nenguva yekuchengetera nguva. ISO New England iri kufunga nezvekuchinja kubva pamaitiro anokodzera (zvinoda nguva-yemaawa maviri) kuenda kune inoshanda-inotakura gadziriro inokoshesa zvirinani kureba-zviwanikwa zvenguva. Pasi pemaitiro aya, mabhatiri emaawa-ane anodhura zvakanyanya-anoshanda kupfuura-masisitimu emaawa maviri uye ane mari yakawanda kudarika magasi matsva kana mari yezvakatipoteredza neyemagariro yabatanidzwa.

Iyo modhi yemari yekuchengetedza bhatiri inosiyana neyechinyakare peakers. Mabhatiri anogona kuwana mari kuburikidza neakawanda grid masevhisi: frequency regulation (inotungamira mari sosi), simba arbitrage (kutenga magetsi kana yakachipa, kutengesa kana ichidhura), uye kubhadhara kwesimba. Tsvagiridzo inoratidza frequency regulation inopa yakawanda yekudzoka kwehupfumi, kunyangwe mukana uyu unogona kudzikira sezvo kuchengetwa kwakawanda kunopinda mumusika uye kukwikwidza kweaya masevhisi kunowedzera.

Kuparara kwebhatiri kunomiririra kunetseka chaiko kwekushanda. Lithium-ion maseru anopera nechaji-inobuditsa, zvinoda kuwandisa panguva yekuisa kuitira kuchengetedza kushanda kwehupenyu hwemakore 10-15. Ongororo yemapurojekiti ekuCalifornia peaker replacement yakawana kuti nzvimbo dzinoda pakati pe8 ne62 full charge-yakaenzana-yakaenzana pagore, neavhareji yema cycles 27 pagore. Mwero wakaderera uyu wekuchovha bhasikoro unokodzera tekinoroji yelithium-ion, sezvo mabhatiri achiwanzobata 5,{13}} macycles asati anyanya kuparara.

Iyo yechinyakare peaker pfungwa iri kushanduka. Nhoroondo, zvidyarwa izvi zvakasimudzwa kusvika ku100% mutoro nekukurumidza sezvinobvira, zvakamhanya panguva yekukwirira, ndokuvhara. Kuwedzera kwesimba rinogonekazve kwagadzira chikamu chitsva: mutoro-unotevera gwenya remagetsi.

Mitoro-zvinomera zvinotevera zvinoshanda zvakasiyana-siyana kwemaawa akareba, zvichiramba zvichigadzirisa zvinobuda kuti zvienzane. Pane kuti vapindure kunhamba dzepamusoro-soro dzinofungidzirwa zuva nezuva, dzinotsiva kweminiti{{2}ku{3}}maminiti ekushanduka kwemhepo uye zuva. Basa iri rinoda nguva dzekupindura nekukurumidza, kunyanduka, uye kazhinji zero-miniti yekutanga kugona. Zvimwe zvigadziriso zvave kusanganisa maturbine egasi nekuchengetedza mabhatiri-mabhatiri anopa mhinduro nekukurumidza apo maturbine ari kutanga, ipapo turbine inotora nguva yakareba{8}}inoda nguva.

Shanduko iyi inodzima mutsetse uri pakati pekukwirisa nekutakura-mabasa anotevera. Kumisikidzwa kwemazuva ano kunofanirwa kubata mabasa ese ari maviri, kushanda pamitoro yakasiyana uye kupindura kune shanduko yekupa kwete kungodiwa shanduko. Musiyano uripo pakati pepeaker nechirimwa chepakati unova usinganyanyi kukosha mumagridi ane kukwirisa kunogonesa kupinda.

Peaker Plants

Nzira dzinoverengeka dziri kubuda kuti dzive dzakachena dzekukwira kumusoro. Hydrogen{{1}maturbine egasi anokwanisa anomiririra nzira imwe chete. Mitsubishi Power yakagadzira maturbine anorema-anokwanisa kupisa 30% hydrogen co-nhasi, achikwanisa kushandura hairojeni yakazara mune ramangwana. Maturbine aya anogona kucheka kuburitswa kweCO2 ne65% zvichienzaniswa nezvirimwa zvemarasha zvechinyakare uku achichengetedza kukurumidza kupindura kugona kwakakosha pakuita basa repamusoro. Mapurojekiti maviri ekuNorth America anoshandisa maturbines aya mukukwirisa maapplication akaiswa kuti asvike kushanda kwekutengesa mukati memakore maviri kusvika mana anotevera.

Hybrid masisitimu anosanganisa renewable nekuchengetedza anopa imwe mhinduro. Arizona Public Service yakaita kondirakiti ye65 MW yemagetsi ezuva akabatanidzwa ne50 MW, 135 MWh lithium-ion bhatiri bhangi rinounza simba panguva yekudiwa kwakanyanya kubva 3:00 kusvika 8:00 PM. Florida's yakarongwa 409-megawatt Manatee system ichabhadhariswa neiri padyo solar plant, kutsiva maviri echembere gasi mayuniti.

Virtual power plant (VPPs) aggregated akagoverwa simba rekushandisa-solar pamusoro pedenga, kuchengetedza bhatiri, smart thermostats, magetsi emotokari charger{1}}uye anoashandisa pamwe chete. Tsvagiridzo yakaitwa neBrattle Boka inoratidza kuti VPPs inogona kupedzisira yapa huwandu hwakafanana sezvidyarwa zvepeaker pamutengo wakaderera uye kubuda. Zvirongwa zvekupindura zvinodikanwa, uko vashandisi vanodzikisa kunwiwa panguva dzepamusoro-soro kuitira kuti vawane muripo, zvinopa imwe nzira yekupa-kumativi kwepamusoro.

Kuchengeta bhatiri kuri kuhwina mumakwikwi ehutsva hwekukwira mumatunhu ane hukasha hwesimba rakachena. California's 2050 carbon-neutral grid mandate yakabvisa zvinobudirira zvirimwa zvitsva zvegasi kubva pamvumo yemutemo. Massachusetts, New York, nedzimwe nyika dzinoverengeka dzakaisa zvibodzwa zvekuchengetedza simba mugigawatt renji panosvika 2025-2030, vachigadzira dura rekuchengetedza senzira yekutsiva peaker.

Shanduko inotarisana nekumhanya kwakasiyana mumatunhu. Nyika dzine gasi rakachipa rakachipa uye mitemo yemamiriro ekunze ine hukasha inoramba ichifarira vanokwira gasi. Zvirongwa zveFlorida zvakabatanidzwa zvichiri kubatanidza gasi idzva-simba rinopfurwa segridi-chishandiso chekuenzanisa. Zvakadaro, kunyangwe pasina kudzvanyirirwa nepolicy, mitengo yelithium-inodonha iri kuita kuti mabhatiri akwikwidze pahupfumi hwakachena mumisika mizhinji.

Mazhinji aripo eUS emafuta emafuta emagetsi emagetsi achasvika kumagumo ehupenyu hwavo hwekushanda panosvika 2035. Sezvo vachembera vanoenda pamudyandigere, sarudzo pakati pekutsiviwa nematurbine egasi matsva kana kuchengetedza kwebhatiri kunowedzera kurerekera kumabhatiri. Ongororo munzvimbo pfumbamwe dzakaona zvidyarwa zvine nhongonya izvo zvinonyanya kutsiva vamiriri zvichienderana nezera, huwandu hwekuburitsa, uye nzvimbo munharaunda dzinotambura. Vazhinji vane makore anodarika makumi matatu ekuberekwa vane mwero wakakwira wekusvibiswa kwetsvina uye zvinhu zvakaderera-chaizvo mamiriro ekuchengetedza bhatiri anoratidza kukwezva zvakanyanya mune zveupfumi.

Vatsoropodzi vekukurumidza peaker pamudyandigere vanonetseka nezve kuvimbika kwegridi panguva yezviitiko zvakanyanyisa. Nhaurirano inotangira paruzivo rwetekinoroji maringe nemhinduro dziri kubuda: maturbine egasi ane makumi emakore enhoroondo yekushanda, ukuwo utility-chikero chekuchengetedza bhatiri chiri chitsva. Pamusoro pezvo, mamiriro ekunze asina kunaka anogona kukanganisa kupihwa uye kudiwa panguva imwe chete-kutonhora kwechando kunogona kuderedza kushanda kwebhatiri uku uchiwedzera kupisa.

Vatsigiri vanopokana kuti mabhatiri anopa kuvimbika zvakanakira gasi zvidyarwa hazvienderane. Nguva yekupindura yakayerwa muzvikamu zvesekondi inobvumira mabhatiri kudzikamisa grid frequency isati yanonoka midziyo yaita, zvichigona kudzivirira kutadza kudonha panguva yekudzima. Geographic kugovera kweakawanda madiki ekuisa mabhatiri anogadzira redundancy kana ichienzaniswa neyepakati peaker zvidyarwa. Uye mabhatiri akabatanidzwa mumamicrogrids anogona kupa simba panguva yekudzima grid, kuwedzera kusimba kwenzvimbo.

Chokwadi chinogona kunge chinoda nzira yepodfolio. Zvidzidzo zvinoratidza musanganiswa wemabhatiri emaawa mana-emazuva ese ekuveura ndebvu, kureba{2}}unyanzvi hwekuchengeta nguva-yezviitiko zvemazuva mazhinji, kuchengetedzwa kwegasi panguva dzenjodzi dzakanyanyisa, kuwedzera kutapurirana kugovera zviwanikwa munzvimbo dzese, uye zvirongwa zvekuda kuchinjika zvese zvinobatsira kumagridi akavimbika asina kutsamira peturu.

Baseload zvirimwa zvinogara zvichimhanya kuti zvizadzise kudiwa kwakatsiga, ukuwo mapeaker maplants anobatika panguva ye-yakanyanya kudiwa. Baseload zvivakwa zvinotungamira kushanda zvakanaka uye kuderera kwemitengo yekushandisa sezvo ivo vachigadzira magetsi nguva dzese. Peakers vanokoshesa kutanga nekukurumidza uye kuchinjika kunyangwe vachidhura zvakanyanya kushanda pachikamu chemagetsi, nekuti vanomhanya mazana mashoma maawa pagore.

Mazuva ano gasi turbine peakers anogona kutanga uye kusvika kuzere kubuda mumaminetsi mashanu kusvika gumi nemashanu. Iyi nguva yekupindura nekukurumidza ndiyo hunhu hwavo hwakakosha. Kana tichienzanisa, zvidyarwa zvemarasha zvinogona kutora maawa kuti zvitange, uye zvidyarwa zvenyukireya zvinoshanda zvakaramba nekuti hazvigone kugadzirisa kubuda nekukurumidza. Bhatiri rekuchengetedza rinopindura zvakatokurumidza, richisvika pakubuda kwakazara mumamilliseconds.

Hongu, mumisika zhinji. Maawa mana-lithium-mabhatiri emaion masystem ave kudhura zvishoma pane mapeakers matsva egasi pamwero wakaenzana munyika dzakawanda. Kunyanya hupfumi kunoenderana nemitengo yemagetsi emunharaunda, mitemo yemusika wemagetsi, mutengo wegasi chaiwo, uye zvinokurudzira. Mutengo wakanakira mabhatiri wakasimba mumatunhu ane yakakwirira renewable kupinda uye yakasimba mutengo volatility.

Zviitiko zvemamiriro ekunze akawedzerwa zvinopa dambudziko guru rekutsiviwa kwebhatiri kwemapeakers. Nepo mabhatiri achikwirisa pamazuva matatu{-ku{2}}pa-maawa{3}}akakwirira emazuva ese, anonetsekana nekugara-kudiwa kwemazuva akawanda. Mapekeri egasi anogona kuramba achimhanya chero bedzi mafuta achienderera mberi. Kuganhurirwa uku kunoreva kutsiva gasi zvakakwana kunoda nguva yakareba-unyanzvi hwekuchengeta kana kuchengetedza gasi pazviitiko zvisingawanzoitiki.

Peaker Plants

Peaker zvidyarwa zvinomiririra tekinoroji yekuchinja mumagidhi emagetsi anoenda ku decarbonization. Kugona kwavo kukurumidza kupindura kunoramba kwakakosha pakugadzikana kwegridi, asi nzira yenhoroondo yekupa kugona uku kuburikidza nekupisa kwemafuta efossil iri kupikiswa nebhatiri simba rekuchengetedza masisitimu anopa mhinduro nekukurumidza, zero kuburitsa, uye kuwedzera kukwikwidza hupfumi.

Shanduko haizoitike zvakafanana kana husiku. Misika ine hukasha mamiriro ekunze uye yakakwirira renewable kupinda ari kutochinja mari kubva gasi kuenda kumabhatiri. Matunhu ane mafuta ezvicherwa akachipa uye kushomeka kwemitemo inoenderera mberi nekuvaka mapeakers. Mubvunzo wakaoma hausi wekuti mabhatiri achatsiva huwandu hwepamusoro, asi mutsara wenguva uye kuti magidhi achasangana sei nekuvimbika zvinodiwa panguva yekuchinja.

Kune vashandi vegridi, zvishandiso, uye vanogadzira masimba emagetsi, kushanduka kwekukwira kwepamusoro kunoda kuenzana zvinokwikwidza zvinotanga: kuchengetedza kuvimbika uku uchideredza kuburitswa, kutonga mari uchikwidziridza zvivakwa, uye kuve nechokwadi chekuenzana kwesimba uchishandura musanganiswa wechizvarwa. Iyo tekinoroji iripo kuti decarbonize peaking kugona. Kuitwa kunoenderana nehurongwa hwematongerwo enyika, dhizaini yemusika, uye sarudzo dzekudyara dziri kuitwa nhasi dzinozogadzira masisitimu emagetsi kwemakumi emakore anotevera.