Eli phepha lijolise kwiingxaki zomthwalo ophantsi wamandla kunye nokutshaja okunzima kwiindawo zasemaphandleni, lichaza icebo lokwakha indawo yokugcina kunye nokutshaja ye-optical edibeneyo kwiindawo zasemaphandleni, kwaye lizisa iindlela ezicacileyo zokusetyenziswa kwecebo.
Iziphumo zibonisa ukuba ukwakhiwa kwezikhululo zokutshaja ezidityanisiweyo zokugcina umbane kunye nezikhululo zokutshaja ezidityanisiweyo kwiidolophu kunokuphucula kakhulu ukusebenza kakuhle kombane, kwaye kunokunciphisa iindleko zotyalo-mali kunye neendleko zokusebenza.
Ukubaluleka kokwakha isikhululo sokugcina kunye nokutshaja esidibeneyo
Njengoko inani lezithuthi zombane lisanda, imfuno yokutshaja iyanda. Ukuba ayilawulwa kakuhle, iya kukhokelela ekuchithweni okukhulu kwamandla ombane kwinkqubo yokutshaja kwezithuthi zombane, ize emva koko izise uxinzelelo olukhulu kwinkqubo yethu yamandla. Ukwakhiwa kwesikhululo sokutshaja esidibeneyo sokugcina izinto ezibonakalayo kunye nokutshaja kunokusombulula ngempumelelo ezi ngxaki zingasentla.
Isikhululo sokutshaja esidibeneyo yindlela entsha yesikhululo sokutshaja, esebenzisa ubuchwepheshe bokuvelisa umbane we-photovoltaic kunye nokugcina amandla kwisikhululo sokutshaja ukubonelela ngesisombululo esifanelekileyo sokutshaja izithuthi zombane.
Kule ndlela, ukuveliswa kwamandla e-photovoltaic kunokudluliselwa ngqo kwisikhululo sokutshaja ngokusebenzisa igridi eqhagamshelweyo, kwaye emva koko ngokutshaja ibhetri inokubonelela ngombane kwizithuthi zombane; Itekhnoloji yokugcina amandla kukusetyenziswa kwezixhobo zokugcina amandla ezisasazeke kwigridi, xa umsebenzisi kufuneka anikezele ngombane kwigridi. Xa kuthelekiswa nesikhululo sokutshaja sendabuko, isikhululo sokutshaja esidibeneyo sokugcina kunye nokutshaja sinokuphucula ngokufanelekileyo ukusebenza kakuhle kwenkqubo yamandla.
Isikhululo sokutshaja esidibeneyo sokugcina nokutshaja kwe-optical sinokunciphisa ngokufanelekileyo iindleko zokutshaja kombane kunye neendleko zokusebenza ngexesha lenkqubo yokutshaja kwezithuthi zombane.
Phantsi kwale modeli, iinkqubo ze-PV kunye nokugcinwa kwamandla ziya kuqhubeka zisebenza de igridi iphelelwe ngumbane, kwaye intlawulo eveliswa ngexesha lenkqubo yokutshaja kwezithuthi zombane iya kugutyungelwa zizikhululo zokutshaja ezihlanganisiweyo.
Kubasebenzisi, le modeli ayinakonga iindleko kuphela, kodwa ikwanokunciphisa ngempumelelo inkunkuma yamandla. Kwinkqubo yokusebenza yokwenyani, indawo yokugcina kunye nokutshaja ye-optical inokufezekisa iingenelo eziphezulu zoqoqosho nezentlalo ngokuphucula uqwalaselo kunye nolawulo lweshedyuli.
Ngoko ke, kunokuthiwa indawo yokugcina izinto ezibonakalayo kunye nesikhululo sokutshaja esidibeneyo luhlobo olutsha lwesikhululo sokutshaja esinamathuba amahle ophuhliso.
Uhlalutyo lwemeko yangoku yokwakhiwa kwegridi yombane kwiindawo zasemaphandleni
Ukwakhiwa kwegridi yombane kwiindawo zasezidolophini
Okwangoku, igridi yombane yelizwe lethu isekwinqanaba lesakhiwo segridi yombane yendabuko esekelwe kwisakhiwo sayo, ikakhulu ngemigca ephezulu, ukuzisebenzela kwenethiwekhi yokusasazwa, ukwenziwa kwedijithali kunye nezinye iindlela zobuchwepheshe bale mihla azanelanga, uninzi lweedolophu kunye neelali azikabinawo umbane. Kukho iingxaki ezintlanu ekwakhiweni kwegridi yombane kwiindawo zasemaphandleni zelizwe lethu.
1). Inqanaba eliphantsi lokuzenzekelayo kwenethiwekhi yokusasazwa kwezinye iilali needolophu, inkqubo yokuzenzekelayo yenethiwekhi yokusasazwa engagqibelelanga, kunye nokungabikho kokubeka esweni ngexesha langempela kunye nesilumkiso kwangethuba sokusebenza kwenethiwekhi yokusasazwa, kuchaphazela kakhulu ukusebenza okuqhelekileyo kwenkqubo yokuzenzekelayo kwenethiwekhi yokusasazwa kwiilali nakwiidolophu.
2). Irediyasi yokuhambisa umbane inkulu kwezinye iindawo zasemaphandleni, nto leyo eyenza ukuba umbane ungakwazi ukufinyeza irediyasi yokuhambisa umbane ngokufanelekileyo.
3). Ulwakhiwo lwenethiwekhi yokusasazwa kwezinye iindawo zasemaphandleni lunento enkulu yokwaluphala, kwaye eminye imigca yokusasazwa ikwanazo neengxaki ezifana necandelo elincinci le-conductor cross, ububanzi obuncinci bentambo kunye nokuguga kwezixhobo.
4). Kukho iingxaki ezithile kwindlela yokulungisa imbuyekezo yamandla okusabela kwezinye iindawo zasemaphandleni, njengokungabikho kwezixhobo ngokwaneleyo kunye nomthamo wembuyekezo yamandla okusabela.
5). Amashishini ombane kwezinye iilali needolophu awanazo iindlela zolawulo zesayensi nezifanelekileyo, ucwangciso kunye noyilo, kunye nohlalutyo kunye nokuqikelela ukusetyenziswa kombane kwicala lomsebenzisi.
Ulwakhiwo lwamandla kwindawo yedolophu
Ulwakhiwo lwamandla kwiindawo zasemaphandleni luphawulwa kukungcola okuphezulu, ukusetyenziswa kwamandla aphezulu kunye nokusebenza kakuhle okuphantsi.
Ngenxa yophuhliso olukhawulezileyo loqoqosho lwaseTshayina, imigangatho yokuphila yabantu iyaqhubeka nokuphucuka, imfuno yamandla nayo iyanda, inani elikhulu lokusetyenziswa kwamandla efosili, nto leyo ekhokelela ekwandeni kongcoliseko lokusingqongileyo.
Kwiminyaka yakutshanje, ulwakhiwo lwamandla kwiindawo zasemaphandleni luye lwaphuculwa kwaye lwaphuculwa, kwaye inqanaba lokusetyenziswa kunye nobungakanani bamandla acocekileyo liye landa ngokucacileyo.
1). Umthamo womthwalo kwiindawo zasemaphandleni mncinane, kwaye abemi basemaphandleni basebenzisa umbane omncinci kwaye ikakhulu basebenzisa izixhobo zombane ezisebenzisa umbane omncinci.
2). Inani lezithuthi zombane (EVS) kwiindawo zasemaphandleni liyanda. Ii-EVS ziqhutywa ngamandla ombane, kwaye zisebenzisa inkqubo yamandla ombane ukubonelela ngamandla ancedisayo. Ukwanda kwenani lee-EVS ngokuqinisekileyo kuya kubangela ukwanda komthwalo wombane.
3). Ulwakhiwo lombane kwiindawo zasemaphandleni alunangqiqo. Ngenxa yokusetyenziswa kombane okuphantsi, ulwakhiwo lombane omnye kunye nokungabikho kocwangciso noyilo lwesayensi nolufanelekileyo, kunzima ukuhlangabezana neemfuno zombane kwiindawo zasemaphandleni.
4). Kukho ukuxinana okukhulu kwiindawo zasemaphandleni, ezinye zazo zineengxaki ze-voltage ephantsi kunye nomgca wokuguga, nto leyo echaphazela kakhulu ukusebenza ngokukhuselekileyo nangokuzinzileyo kwenkqubo yombane.
Umgangatho wombane wenethiwekhi yokusasazwa kwempahla kwindawo yasedolophini
Umgangatho wamandla yenye yezinto ezibalulekileyo ezichaphazela umgangatho wobomi babemi basemaphandleni, kwaye yenye yezona ngxaki ziphambili ekufuneka zisombululwe ngamashishini ombane. Okwangoku, umgangatho wamandla wenethiwekhi yokusasazwa kwezixhobo kwiindawo zasemaphandleni ujongene ikakhulu nezi nkalo zintathu zilandelayo zengxaki.
1). Ukuphambuka kwe-voltage kwinethiwekhi yamandla asemaphandleni kukhulu, kwaye i-voltage yabanye abasebenzisi ibonakala iphambuka engalunganga.
2). Inqanaba lokungalingani kwe-voltage yesigaba sesithathu yenethiwekhi yokusasazwa kwezinye iilali kunye needolophu lingaphaya komgangatho wesizwe.
3). Kukho izinto ezingaqhelekanga kakhulu ezimalunga nokungalingani kweendlela ezintathu kuthungelwano losasazo kwiindawo zasemaphandleni, nto leyo ekhokelela kwingxaki yomgangatho wamandla kwicala labasebenzisi.
Uphononongo lwetyala malunga nokwakhiwa kwesikhululo sokugcina kunye nokutshaja esidibeneyo se-optical
Ukuze kukhuthazwe ngcono uphuhliso loqoqosho lweendawo zasemaphandleni, urhulumente ukhuthaza ngamandla ukwakhiwa kwezikhululo ezintsha zokutshaja umbane. Okwangoku, kusekho iingxaki ezithile ekwakhiweni kwezikhululo ezintsha zokutshaja umbane kwilizwe lethu, umzekelo, indawo yezikhululo zokutshaja kunzima, ukusetyenziswa okuphantsi kwezixhobo zokutshaja, ukusebenza kakuhle kokutshaja.
Ngenxa yesi sizathu, ilizwe lethu laqala ukukhawulezisa ukwakhiwa kwezikhululo zokutshaja iimoto zombane. Ukuze kusonjululwe ingxaki yokutshaja iimoto zombane kwiindawo zasemaphandleni, isikhululo sokutshaja esidibeneyo sokugcina nokutshaja kwe-optical sinokwakhiwa kwiindawo zasemaphandleni.
Isikhululo sokutshaja esidibeneyo sinamacandelo amathathu: inkqubo yokuvelisa umbane we-photovoltaic, inkqubo yokugcina umbane kunye nesikhululo sokutshaja. Kwinkqubo yokwakha, kuyimfuneko ukwakha inkqubo yokuvelisa umbane we-photovoltaic kuqala, uze emva koko usebenzise inkqubo yokugcina umbane ukulawula ukutshaja kwezithuthi zombane.
Ukongeza, kuyimfuneko ukuseta isithuba sokutshaja se-AC kunye nesithuba sokutshaja se-DC kwisikhululo sokutshaja ukuze kube lula ukutshaja kwezithuthi zombane.
Lilonke, inqanaba lophuhliso loqoqosho lweendawo zasemaphandleni liphantsi kakhulu, ngoko ke iindleko zokwakha izitishi zokutshaja ezidityanisiweyo zokugcina ukukhanya kunye nokutshaja ziphantsi kakhulu. Ukuthatha umzekelo wedolophu, inqanaba loqoqosho lwedolophu likwinqanaba eliphakathi kweli lizwe, kwaye ukwakhiwa kwesitishi sokutshaja esidityanisiweyo sokugcina ukukhanya kunye nokutshaja kunokufezekisa iingenelo zoqoqosho ezilungileyo.
1). Idolophu ngokwayo inezixhobo zokukhanya ezaneleyo kunye nezixhobo zomhlaba, ezinokusetyenziswa ngokupheleleyo ukwakha isikhululo sokutshaja esidibeneyo sokugcina nokuhlawula izibane.
Kuyilo lwe-optical storage kunye ne-charge station edibeneyo, kufuneka kuqala ukhethe izixhobo zokwakha ezifanelekileyo kunye nefom yesakhiwo, uze emva koko udibanise nendawo yendawo kunye neemeko zemozulu ukuze uyile.
Umzekelo, idolophu ngenxa yemozulu ebandayo, ukukhanya okwaneleyo, imithombo yomhlaba ingaphezulu kakhulu, ungakhetha iiphaneli ze-photovoltaic ukwakha indawo yokugcina kunye nesikhululo sokutshaja esidibeneyo.
2). Inkqubo ye-PV inoxanduva olukhulu lokutshaja izithuthi zombane, ngelixa inkqubo yokugcina amandla inoxanduva lokugcina umbane. Inkqubo ye-PV kunye nenkqubo yokugcina amandla kufuneka zidityaniswe ngendlela efanelekileyo ngexesha lokwakha.
Ukongeza, kuyimfuneko ukumisela ngokufanelekileyo umthamo kunye nobungakanani bebhetri yokugcina amandla kunye nebhetri yokugcina amandla kwinkqubo yokugcina amandla. Umthamo webhetri kufuneka umiselwe ngokwemfuno yokutshaja yesithuthi sombane. Ngokubanzi, umthamo webhetri unokuqinisekiswa ngokwemeko yokusetyenziswa, indawo kunye nemfuno yemarike yesithuthi sombane. Ngenxa yesi sizathu, ixesha lokutshaja kunye nokusebenza kakuhle kokutshaja kwesithuthi sombane kufuneka kuyilwe ngokufanelekileyo.
3). Isikhululo sokutshaja esidityanisiweyo sokugcina izinto ezibonakalayo kunye nesikhululo sokutshaja kufuneka silungiselele ngokufanelekileyo izixhobo ezahlukeneyo zesikhululo sokutshaja.
Ekwakhiweni kwesikhululo sokutshaja esidibeneyo kufuneka uzame ukukhetha umgangatho olungileyo, ukusebenza okuzinzileyo kwezixhobo ukuze kuthintelwe ukusilela kwezixhobo kunye nokuchaphazela ukusebenza okuqhelekileyo kwesikhululo sokutshaja.
Ukongeza, ulawulo olukrelekrele lwendawo yokugcina izinto ezibonakalayo kunye nesikhululo sokutshaja esidibeneyo sinokufezekiswa ngokuphucula inqanaba elikrelekrele lesikhululo sokutshaja.
4). Emva kokwakhiwa kwesikhululo sokutshaja esidibeneyo, kuyimfuneko ukwenza umsebenzi wokwamkelwa novavanyo lwesikhululo:
① Kufuneka ihambelane nemigangatho yesizwe kunye nemigangatho yoshishino ukuze yamkelwe;
② Ingaba ulwakhiwo lwayo luyahambelana neemfuno zomgaqo-nkqubo wengingqi kunye neemfuno zomsebenzisi ukuze zamkelwe;
③ Ifanele yamkelwe ngenxa yokusebenza kwayo okuqhelekileyo. Umsebenzi wovavanyo ubandakanya ikakhulu ezi zinto zimbini zilandelayo: ① Ingaba isikhululo sokutshaja siyahambelana nemigangatho yokutshaja kunye nemigangatho enxulumene nayo kufuneka sivavanywe; ② Ingaba isikhululo sokutshaja siyahambelana nemigaqo yokhuseleko kunye nemigangatho enxulumene nayo kufuneka sivavanywe.
Ugcino lwe-Optical kunye nokutshaja okudibeneyo komthamo wenqwaba yokutshaja
Ixesha lokutshaja lesithuthi sombane lichaphazeleka kakhulu ngamandla kunye nexesha lokutshaja lesithuthi sombane, oko kukuthi, ixesha lokutshaja lebhetri kunye nexesha lokutshaja lobungakanani bombane.
Kungoko ke, kuyimfuneko ukuqikelela ixesha lokutshaja ngokwemandla esithuthi sombane. Okwangoku, akukho mgangatho udibeneyo weenqwaba zokutshaja kwilizwe lethu, kwaye ixesha lokutshaja kweenqwaba zokutshaja zeempawu ezahlukeneyo lahlukile kakhulu, ngoko ke singasebenzisa ezinye iindlela zokuqikelela ixesha lokutshaja kweenqwaba zokutshaja. Iinqwaba zokutshaja zahlulwe ngokwe-4H, 12h kunye ne-16h ngokulandelelana.
Ngokwendlela engentla, ixesha lokutshaja kwenqwaba yokutshaja linokulinganiswa, kwaye ixesha lokutshaja kwenqwaba yokutshaja enobume obahlukeneyo bomthamo linokufunyanwa. Ekwabiweni komthamo weenqwaba zokutshaja, kufuneka siqwalasele ngokupheleleyo iimpawu zabemi basemaphandleni kunye neemfuno zokutshaja kwezithuthi zombane.
Amanqanaba ombane ahlukeneyo kwizithuthi zombane afuna amandla ahlukeneyo, ngoko ke ngokweemfuno zolungiselelo lwezixhobo zesikhululo sokutshaja.
Kwiimeko eziqhelekileyo, abemi basemaphandleni abanamanqanaba ombane angama-220V kunye nama-110V, ngoko ke ekwakhiweni kwezikhululo zokutshaja kufuneka baxhotyiswe ngamanqanaba ombane ahambelanayo eenqwaba zokutshaja.
Umzekelo, thabatha iphondo lase-Anhui, phantsi kweemeko eziqhelekileyo, amanqanaba ombane kwiindawo zasemaphandleni angama-10 kv kunye nama-35 kv. Ngokunyuka kwamandla ezithuthi zombane kunye nokuncipha kwexesha lokutshaja, ixesha eliqhelekileyo lokutshaja liya kuncipha kancinci kancinci.
Iprojekthi edibeneyo yokugcina izinto ezibonakalayo kunye nesikhululo sokutshaja
Uhlalutyo lwenzuzo yezoqoqosho
Isitishi sokutshaja esidibeneyo esineentlobo ezine zamandla yi-120kW, 250KW, 400kW kunye ne-600kW. Kufunyaniswe ukuba izinga langaphakathi lembuyekezo yi-10.24% kwaye ixesha lokubuyisela liyiminyaka eyi-3.65 xa amandla eyi-120kw.
Ngenxa yenani elincinci lezithuthi zombane kunye nemfuno ephantsi yokutshaja kwilizwe lethu, singakhetha iprojekthi enomthamo omncinci yokwakha isikhululo sokutshaja esidibeneyo, ukuze sihlangabezane neendawo zasemaphandleni ezikhoyo ngoku zeemfuno zokutshaja izithuthi zombane.
Ukwakhiwa kwesikhululo sokugcina kunye nesokutshaja esidibeneyo
Ubunzima bezobugcisa kunye nezisombululo
Ezi ngxaki zilandelayo zobugcisa kufuneka zisonjululwe ukuze kuphuhliswe ngakumbi iindawo zokugcina nokufaka i-optical ezidibeneyo kwiindawo zasemaphandleni.
1). Uyilo nokwakhiwa kwenkqubo yokugcina amandla kwicala lomsebenzisi. Uyilo nokwakhiwa kwenkqubo yokugcina amandla kwicala lomsebenzisi ngundoqo ekwakhiweni kwesikhululo sokugcina kunye nokutshaja esidibeneyo kwiindawo zasemaphandleni.
2). Ulawulo oludibeneyo lwenkqubo yokuvelisa umbane we-photovoltaic kunye nenkqubo yokutshaja. Kubalulekile ukuqwalasela ngokupheleleyo ulungelelwaniso kunye nolawulo phakathi kwenkqubo yokuvelisa umbane we-photovoltaic kunye nenkqubo yokutshaja xa kusakhiwa isikhululo sokutshaja esidibeneyo kwiindawo zasemaphandleni. Ulawulo oludibeneyo phakathi kwenkqubo yokuvelisa umbane we-photovoltaic kunye nenkqubo yokutshaja luquka ikakhulu iinkalo ezimbini:
Kwelinye icala, lulawulo oludibeneyo phakathi kwenkqubo yokuvelisa umbane we-photovoltaic kunye nenkqubo yokugcina umbane, kwelinye icala, lulawulo oludibeneyo phakathi kwenkqubo yokuvelisa umbane we-photovoltaic kunye nenkqubo yokutshaja.
Isilawuli sokutshaja nokukhupha umbane, umlawuli wamandla kunye nezinye izixhobo zinokusetyenziswa ukulungelelanisa ulawulo phakathi kwenkqubo yokuvelisa umbane we-photovoltaic kunye nenkqubo yokugcina umbane.
Xa amandla okukhupha amandla enkqubo yokuvelisa umbane we-photovoltaic anganelanga, amandla agqithisileyo anokugcwaliswa kwakhona kwisikhululo sokutshaja ngexesha ngumlawuli wokutshaja nokukhupha, umlawuli wamandla unokusetyenziswa ukunciphisa amandla okuvelisa i-photovoltaic, ngaloo ndlela kuthintelwe ukutshaja kakhulu.
Ukongeza, i-super capacitor ingasetyenziselwa ukufezekisa umsebenzi wokutshaja wezixhobo zokuvelisa umbane ze-photovoltaic.
3). Icebo lokulawula eliqhagamshelwe kwisitishi sokutshaja. Kwiimeko eziqhelekileyo, iigridi zamandla ezincinci kwiindawo zasemaphandleni zikhokelela ekungazinzini okuqhagamshelwe kwigridi. Ukuze kuqinisekiswe ukhuseleko lokusetyenziswa kwamandla kwiindawo zasemaphandleni, inani elikhulu lombane osasazekileyo kwigridi yamandla kufuneka lilawulwe kwaye lilawulwe ngumlawuli oqhagamshelwe kwigridi.
Kwangaxeshanye, umbane osasazekileyo unokuqhagamshelwa kwigridi yamandla ngesixhobo sokuguqula icala legridi.
Ukongeza, kuyimfuneko ukusebenzisa ibhetri, i-super capacitor kunye nezinye izixhobo ukuze kufezekiswe ulawulo oludibeneyo lombane osasazwayo.
4). Uyilo lolawulo lokusasazwa kwamandla kwisikhululo sokutshaja. Ngokubanzi, xa umthamo wokugcina amandla kwicala lomsebenzisi unganelanga, amandla agqithisileyo anokongezwa kwisikhululo sokutshaja ngesixhobo sokuguqula amandla esibhekisa kwicala ngalinye, kwaye xa umthamo wokugcina amandla kwicala lomsebenzisi wanele, ukusetyenziswa kwee-super-capacitors kunokusetyenziswa ukutshaja nokukhupha izixhobo zokuvelisa umbane ze-photovoltaic.
5). Ukugcinwa nokusebenza kunye nolawulo lwendawo yokugcina izinto ezibonakalayo kunye nesikhululo sokutshaja esihlanganisiweyo. Ngokukodwa, kubandakanya ezi zinto zisixhenxe zilandelayo: ① Ukuyila isicwangciso somsebenzi esifanelekileyo; ② Ukuqinisa uqeqesho lwabasebenzi abafanelekileyo; ③ ukuhlola nokugcina izixhobo rhoqo; ④ Ukuseka nokuphucula isikhululo sokutshaja Inkqubo yoLawulo lokuSebenza; ⑤ Ukuququzelela nokuqhuba imisebenzi eyahlukeneyo yoqeqesho rhoqo; ⑥ Ukuseka nokuphucula indlela yokusebenza kunye nokugcinwa kwesikhululo sokutshaja; ⑦ Ukujongana nokusilela kwezixhobo ngexesha elifanelekileyo, njl.
Eli phepha lihlalutya ubuchwepheshe kunye noqoqosho lweeprojekthi zokugcina umbane we-photovoltaic kunye nokugcina umbane, kwaye lifikelela kwisigqibo sokuba kunokwenzeka ukwakha isikhululo sokutshaja esidibeneyo kwiindawo zasemaphandleni.
Le nkqubo ineenzuzo ezilungileyo kwezoqoqosho nakwezentlalo, kwaye iyahlangabezana neemfuno zophuhliso lweshishini elitsha lokuvelisa amandla phantsi kwenjongo ethi "Double carbon" eTshayina. Ngokuqhubeka kweteknoloji entsha yokuvelisa amandla, iteknoloji yokuvelisa amandla e-photovoltaic iya kusetyenziswa kakhulu, iteknoloji yokugcina amandla nayo iya kusetyenziswa kakhulu.
Ngoko ke, ilizwe lethu kufuneka lonyuse uphando malunga nobuchwepheshe obutsha bokuvelisa amandla obuphambili obufana nobuchwepheshe obutsha bokugcina amandla kunye nobuchwepheshe bokuvelisa amandla nge-photovoltaic ukuze kubonelelwe ngenkxaso engakumbi kuphuhliso lweshishini elitsha lokuvelisa amandla.
