澳大利亞擁有世界一流的風、光資源,對于可再生能源項目開發投資具有得天獨厚的優勢。加上澳大利亞多年來穩定的政商環境,其可再生能源投資市場一直備受世界各國電力投資企業的青睞。當前澳大利亞國家電力市場正處于由傳統能源向清潔能源轉型期,澳大利亞能源市場運營機構(AEMO)預測未來20年將有15吉瓦大型燃煤電站因機組老化退出國家電力市場,同期需要新增約26吉瓦大型風電或光伏項目來滿足未來電力需求。AEMO在各州規劃了可再生能源發展區,并制定了短、中、長期電網升級規劃,以支持可再生能源行業的可持續發展。在新冠疫情大流行的背景下,可再生能源行業將成為澳大利亞重振經濟、刺激就業的主要驅動力之一,其投資市場發展前景非常樂觀。
盡(jin)管(guan)近年來澳大利亞可再生能源項(xiang)目(mu)裝(zhuang)機(ji)容量增速較快,但國家(jia)電網(wang)升級改造速度相(xiang)對滯后,引發了(le)例如并(bing)網(wang)申(shen)請期大幅(fu)度延期、并(bing)網(wang)技術(shu)要求(qiu)提高等(deng)與并(bing)網(wang)相(xiang)關(guan)的(de)開發風險。在評(ping)估(gu)投資項(xiang)目(mu)的(de)過程(cheng)中,投資人除了(le)要開展(zhan)對項(xiang)目(mu)的(de)發電技術(shu)、土(tu)地(di)環評(ping)、規劃審批等(deng)常規的(de)盡(jin)職調(diao)查以外,尤(you)其(qi)(qi)要把并(bing)網(wang)風險作為首當其(qi)(qi)沖的(de)風險要素來評(ping)估(gu)。
澳大利亞國家電網概況
基本特征
澳(ao)(ao)大(da)(da)利亞(ya)國(guo)家(jia)電(dian)(dian)力市場(chang)的(de)(de)電(dian)(dian)網(wang)系統(tong)由(you)昆士蘭州(zhou)(zhou)、新南威爾(er)士州(zhou)(zhou)(包(bao)含首都領地(di)堪培拉地(di)區)、維多利亞(ya)州(zhou)(zhou)、南澳(ao)(ao)大(da)(da)利亞(ya)州(zhou)(zhou)和塔斯馬(ma)尼(ni)亞(ya)州(zhou)(zhou)的(de)(de)電(dian)(dian)網(wang)構成,各州(zhou)(zhou)電(dian)(dian)網(wang)通過州(zhou)(zhou)際輸(shu)電(dian)(dian)線(xian)路連接(jie),統(tong)稱為(wei)澳(ao)(ao)大(da)(da)利亞(ya)國(guo)家(jia)電(dian)(dian)力市場(chang)(NEM)。高壓輸(shu)電(dian)(dian)網(wang)絡(luo)將(jiang)各州(zhou)(zhou)大(da)(da)型發電(dian)(dian)機(ji)組(zu)的(de)(de)電(dian)(dian)力直接(jie)傳輸(shu)到大(da)(da)型工(gong)(gong)業用(yong)戶,同時連通分布于(yu)各州(zhou)(zhou)的(de)(de)13個中低壓配電(dian)(dian)網(wang)絡(luo),將(jiang)電(dian)(dian)力傳輸(shu)到工(gong)(gong)商業以及家(jia)庭超(chao)過1千萬個用(yong)電(dian)(dian)端客戶。澳(ao)(ao)大(da)(da)利亞(ya)國(guo)家(jia)電(dian)(dian)網(wang)跨越總長度約5000千米,是世界(jie)上最長的(de)(de)電(dian)(dian)網(wang)之一。
澳大利亞(ya)地廣人(ren)稀(xi),人(ren)口主要(yao)分布(bu)在東南沿(yan)海地區(qu),廣大內(nei)陸地區(qu)人(ren)口較少,發電(dian)(dian)(dian)機組和用電(dian)(dian)(dian)中(zhong)心的(de)(de)地理(li)位置相對分散(san),因此,澳大利亞(ya)輸電(dian)(dian)(dian)網(wang)(wang)絡具(ju)有輸送距(ju)離遠、形狀(zhuang)細長及(ji)密度較低的(de)(de)物(wu)理(li)特征。同時,由于澳大利亞(ya)中(zhong)部內(nei)陸偏遠地區(qu)的(de)(de)用戶數量(liang)較少,其電(dian)(dian)(dian)網(wang)(wang)設施的(de)(de)規模和容量(liang)也相應較小。
澳大(da)利亞煤(mei)(mei)炭資源(yuan)豐富(fu),燃煤(mei)(mei)電(dian)站是其(qi)主要(yao)的(de)(de)(de)電(dian)力來源(yuan)。現有的(de)(de)(de)大(da)型發電(dian)項目270多(duo)個,總(zong)裝(zhuang)(zhuang)機(ji)約為55.8吉(ji)瓦(wa)(wa)。其(qi)中燃煤(mei)(mei)電(dian)站裝(zhuang)(zhuang)機(ji)容量(liang)為23吉(ji)瓦(wa)(wa),占(zhan)41.3%;燃氣電(dian)站裝(zhuang)(zhuang)機(ji)容量(liang)為12.4吉(ji)瓦(wa)(wa),占(zhan)22.2%;由(you)燃煤(mei)(mei)和(he)燃氣電(dian)站組成(cheng)的(de)(de)(de)傳統石(shi)化能源(yuan)占(zhan)國(guo)家電(dian)力市場總(zong)裝(zhuang)(zhuang)機(ji)容量(liang)的(de)(de)(de)63%以上。由(you)大(da)型水電(dian)、風電(dian)和(he)光(guang)伏(fu)電(dian)站構成(cheng)的(de)(de)(de)可(ke)再生能源(yuan)項目共(gong)計19.3吉(ji)瓦(wa)(wa),占(zhan)總(zong)裝(zhuang)(zhuang)機(ji)容量(liang)的(de)(de)(de)34%左右(見圖1)。
近年來部分燃(ran)煤(mei)電(dian)站已接近使用年限,由于維(wei)護費用高(gao)昂且存在安全隱(yin)患,部分業主選(xuan)擇關(guan)停(ting)這些電(dian)站。自2014年以(yi)來,澳大利亞國家電(dian)力(li)市場已有約4153兆(zhao)瓦燃(ran)煤(mei)電(dian)站被關(guan)閉(bi),同期新(xin)(xin)增(zeng)了約7722兆(zhao)瓦水電(dian)、風電(dian)和光伏等大型可再(zai)生(sheng)能(neng)源(yuan)發電(dian)項(xiang)目(見圖2)。這些數據表明,澳大利亞能(neng)源(yuan)市場的(de)電(dian)源(yuan)供應開(kai)始從(cong)傳統(tong)能(neng)源(yuan)逐漸過渡到以(yi)可再(zai)生(sheng)能(neng)源(yuan)為代表的(de)新(xin)(xin)能(neng)源(yuan)技術。
據AEMO預(yu)測,從2020~2040年,還將有15吉(ji)瓦(wa)的(de)燃煤(mei)電(dian)(dian)站(zhan)達到設計壽(shou)命(ming)并將被關閉。這(zhe)些規劃退役(yi)的(de)燃煤(mei)電(dian)(dian)站(zhan)年發電(dian)(dian)量(liang)共計約700億(yi)千瓦(wa)時,占國(guo)家電(dian)(dian)力市場總用(yong)電(dian)(dian)量(liang)的(de)1/3。
并網要求
AEMO是管理國(guo)家(jia)電(dian)力市場(chang)(chang)的(de)核心機構,其主(zhu)要職責(ze)包括管理電(dian)力市場(chang)(chang)交易(yi)主(zhu)體的(de)電(dian)力調度與(yu)交易(yi)、發(fa)電(dian)項目注冊與(yu)退(tui)出、對電(dian)力市場(chang)(chang)的(de)供(gong)需進行(xing)預測與(yu)發(fa)布、管理現貨和輔(fu)助服(fu)務(wu)等市場(chang)(chang)的(de)運(yun)行(xing)、確保電(dian)力系統的(de)安全性與(yu)可(ke)靠性等。AEMO運(yun)營管理主(zhu)要重點考慮以下幾(ji)個方面要求:
電(dian)力(li)系統安全性。電(dian)力(li)系統的安全性是指電(dian)力(li)系統按(an)照(zhao)既定的技術標準,在某(mou)些大(da)型發電(dian)機組或(huo)(huo)者輸電(dian)線路等主要系統組成(cheng)(cheng)部(bu)分(fen)失效(xiao)的情況下,仍(reng)然能(neng)正常(chang)運(yun)行(xing)并持續供電(dian)的能(neng)力(li)。在電(dian)網(wang)出現(xian)臨時故障時,AEMO需采取必要措施(shi)(shi)確保故障不(bu)會對電(dian)網(wang)基(ji)礎(chu)設(she)施(shi)(shi)造成(cheng)(cheng)嚴重過載或(huo)(huo)者損(sun)壞。
電(dian)(dian)(dian)(dian)力系(xi)(xi)統(tong)可靠(kao)(kao)性(xing)。電(dian)(dian)(dian)(dian)力系(xi)(xi)統(tong)的(de)(de)(de)可靠(kao)(kao)性(xing)是(shi)指供電(dian)(dian)(dian)(dian)系(xi)(xi)統(tong)在(zai)扣除電(dian)(dian)(dian)(dian)網各個環節的(de)(de)(de)電(dian)(dian)(dian)(dian)力損耗后,還(huan)能持續向用(yong)(yong)(yong)(yong)戶(hu)端提供足夠電(dian)(dian)(dian)(dian)力以滿足客戶(hu)用(yong)(yong)(yong)(yong)電(dian)(dian)(dian)(dian)需(xu)求,電(dian)(dian)(dian)(dian)力的(de)(de)(de)供需(xu)達(da)到實時動態(tai)平(ping)衡(heng)。如果供電(dian)(dian)(dian)(dian)量不能滿足用(yong)(yong)(yong)(yong)電(dian)(dian)(dian)(dian)需(xu)求量,兩(liang)者之間的(de)(de)(de)差額(e)稱之為電(dian)(dian)(dian)(dian)力缺口(kou)。國家電(dian)(dian)(dian)(dian)力市場的(de)(de)(de)可靠(kao)(kao)性(xing)標準規定(ding),每(mei)個區域每(mei)年(nian)的(de)(de)(de)電(dian)(dian)(dian)(dian)力缺口(kou)不能超過該區域當(dang)年(nian)用(yong)(yong)(yong)(yong)電(dian)(dian)(dian)(dian)量的(de)(de)(de)0.002%。
電(dian)力(li)(li)系(xi)統維(wei)護。在(zai)電(dian)力(li)(li)系(xi)統出現故障導致電(dian)力(li)(li)供應不足(zu)的(de)(de)情況下,AEMO有(you)(you)權向尚有(you)(you)儲備功率(lv)的(de)(de)機組發布(bu)行(xing)政指令,強制其增發電(dian)力(li)(li)來(lai)彌補當前的(de)(de)電(dian)力(li)(li)缺口。在(zai)采取(qu)了(le)各(ge)種調度手段后,如(ru)果仍然不能滿足(zu)某個地區的(de)(de)用(yong)電(dian)需求,AEMO有(you)(you)權向電(dian)網公司發布(bu)減載行(xing)政指令,關停(ting)或者下調部(bu)分客戶負載用(yong)電(dian)量,使電(dian)力(li)(li)系(xi)統恢復供需平衡。
并網(wang)申請(qing)管理。國(guo)(guo)家電力市場的并網(wang)申請(qing)流(liu)(liu)程由(you)AEMO配合(he)當地(di)電網(wang)公司聯合(he)完(wan)成。并網(wang)技術審核(he)則統一(yi)由(you)AEMO來按(an)照(zhao)國(guo)(guo)家電力法規(gui)相關技術要(yao)求(qiu)來主導完(wan)成。并網(wang)申請(qing)單(dan)位(wei)可(ke)以直接對(dui)接AEMO和項目(mu)所在州(zhou)的電網(wang)公司。只(zhi)要(yao)并網(wang)點有足(zu)夠并網(wang)容量(或者通過(guo)升級(ji)滿足(zu)容量要(yao)求(qiu))以及滿足(zu)AEMO的并網(wang)技術標準(zhun),申請(qing)單(dan)位(wei)均(jun)獲(huo)得(de)平等機會完(wan)成并網(wang)流(liu)(liu)程獲(huo)得(de)并網(wang)許可(ke)。
突出問題
當前(qian)澳大(da)利亞國(guo)家電(dian)網(wang)中(zhong)大(da)型可再生能源發(fa)(fa)電(dian)機組以(yi)及小型分布式能源增長(chang)迅速,形成數以(yi)百萬(wan)計(ji)的(de)(de)分散并網(wang)點。由于(yu)適合(he)大(da)型光伏和(he)風電(dian)項目所(suo)需(xu)的(de)(de)風、光資源和(he)土地基本(ben)處于(yu)偏遠地區,加之這些地區電(dian)網(wang)設施規模和(he)容量(liang)較(jiao)小,隨著風電(dian)和(he)光伏發(fa)(fa)電(dian)機組大(da)規模涌現,整個(ge)國(guo)家電(dian)網(wang)電(dian)力(li)系統(tong)的(de)(de)安全性(xing)和(he)可靠性(xing)受到(dao)一定程度的(de)(de)影響。
南澳大(da)利亞(ya)州(zhou)(zhou)超(chao)過50%的發電量來自以風電和光伏為(wei)主的可再(zai)生能源機(ji)(ji)組(zu)(zu)。由于(yu)可再(zai)生能源機(ji)(ji)組(zu)(zu)發電具有(you)間(jian)歇性,加上極(ji)端(duan)自然災害天氣突發,州(zhou)(zhou)內儲(chu)備(bei)電源、峰值燃氣機(ji)(ji)組(zu)(zu)還有(you)州(zhou)(zhou)際輸電等(deng)調(diao)度(du)反應不(bu)及時,引(yin)發了2016年9月大(da)停電等(deng)一系(xi)列規模較大(da)的突發事件。
大量(liang)新(xin)(xin)增的(de)(de)(de)可再(zai)生(sheng)能(neng)源(yuan)項目(mu)(mu)導致(zhi)國家(jia)電(dian)(dian)網電(dian)(dian)力(li)潮流(liu)流(liu)向發(fa)生(sheng)改變,2018年(nian)4月(yue),AEMO計算出當(dang)年(nian)昆州北(bei)(bei)部(bu)、新(xin)(xin)州西部(bu)等區域的(de)(de)(de)輸電(dian)(dian)邊(bian)際損耗系(xi)數(shu)(MLF)減少了(le)10%~22%。另外,由于維(wei)州西北(bei)(bei)部(bu)和(he)新(xin)(xin)州西南(nan)部(bu)莫雷河(he)流(liu)域西部(bu)地(di)區(West Murray)的(de)(de)(de)電(dian)(dian)網強度較弱,無法接納更(geng)多(duo)的(de)(de)(de)大型光伏電(dian)(dian)站并網,AEMO宣(xuan)布2019年(nian)9月(yue)開始對該地(di)區5個(ge)大型光伏發(fa)電(dian)(dian)項目(mu)(mu)實施了(le)為(wei)(wei)期數(shu)月(yue)且高(gao)達50%的(de)(de)(de)長期限電(dian)(dian)。為(wei)(wei)了(le)解(jie)決West Murray地(di)區的(de)(de)(de)電(dian)(dian)網技術問題,AEMO動用了(le)幾(ji)乎所有的(de)(de)(de)技術和(he)行(xing)政資源(yuan),導致(zhi)并網申請流(liu)程整(zheng)體效率(lv)大幅下降,并網手續延期成為(wei)(wei)了(le)當(dang)前國家(jia)電(dian)(dian)力(li)市場的(de)(de)(de)常態。
這些事件表明(ming)澳大(da)利亞國家電(dian)網基(ji)礎設施及技術管理、資源水平(ping)或(huo)多或(huo)少制約了可再生能源項目大(da)規模高速發展。
需重點關注的并網技術因素
輸電阻塞和限電
當(dang)電(dian)(dian)網系(xi)統中(zhong)某(mou)處電(dian)(dian)纜或變壓器等達到其設計極限或者出現故(gu)障,導致其無法承載(zai)更多電(dian)(dian)流,就會出現輸電(dian)(dian)阻(zu)塞,造成當(dang)地發電(dian)(dian)機(ji)組(zu)(zu)不能滿功(gong)率發電(dian)(dian),機(ji)組(zu)(zu)也就受到了限電(dian)(dian)。
除了(le)由于(yu)突發(fa)性故(gu)障(zhang)引起的(de)短(duan)暫限(xian)(xian)電(dian)(dian)(dian)(dian)以外,長(chang)期限(xian)(xian)電(dian)(dian)(dian)(dian)主要是因為電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)的(de)輸電(dian)(dian)(dian)(dian)能(neng)力受到電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)部件的(de)物理條件限(xian)(xian)制(zhi)(zhi)。為了(le)維護(hu)電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)安全(quan)性和(he)可靠性,電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)公(gong)司(si)會給(gei)電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)設(she)施工況設(she)置安全(quan)系(xi)數(shu)。電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)基礎設(she)施在這些物理限(xian)(xian)制(zhi)(zhi)和(he)安全(quan)設(she)定下(xia),能(neng)承(cheng)載電(dian)(dian)(dian)(dian)力的(de)最大(da)值,稱為輸電(dian)(dian)(dian)(dian)容量限(xian)(xian)制(zhi)(zhi)。AEMO和(he)電(dian)(dian)(dian)(dian)力公(gong)司(si)需把輸送電(dian)(dian)(dian)(dian)力控制(zhi)(zhi)在允許的(de)輸送容量限(xian)(xian)制(zhi)(zhi)范圍(wei)內(nei),否(fou)則(ze)將(jiang)對電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)設(she)施造成損害,甚至導致電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)系(xi)統局部或大(da)規(gui)模停電(dian)(dian)(dian)(dian)。
解決電(dian)(dian)(dian)網(wang)(wang)擁(yong)堵(du)(du)的根本方法(fa)是對電(dian)(dian)(dian)網(wang)(wang)設(she)施(電(dian)(dian)(dian)纜、變壓器以及保護和控制(zhi)設(she)備(bei)等)進行(xing)升(sheng)級(ji)擴容,降(jiang)低電(dian)(dian)(dian)網(wang)(wang)擁(yong)堵(du)(du)發生的概率,從(cong)而降(jiang)低限(xian)電(dian)(dian)(dian)風險。但是對電(dian)(dian)(dian)網(wang)(wang)升(sheng)級(ji)改造需要(yao)大(da)量的資金投入和耗時的行(xing)政審批,如果升(sheng)級(ji)改造電(dian)(dian)(dian)網(wang)(wang)的成本遠(yuan)超(chao)過限(xian)電(dian)(dian)(dian)成本的話,從(cong)短期來說,對發電(dian)(dian)(dian)單位(wei)限(xian)電(dian)(dian)(dian)就成為AEMO不得已而采取的暫時性措施。
電網系統強度
電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)(wang)(wang)(wang)系統(tong)強(qiang)度(du)是電(dian)(dian)(dian)(dian)(dian)(dian)力系統(tong)的(de)固有特(te)性,是電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)(wang)(wang)(wang)在合理的(de)運行條件下衡(heng)量電(dian)(dian)(dian)(dian)(dian)(dian)力系統(tong)穩定性的(de)重要(yao)參數之(zhi)一(yi)。當電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)(wang)(wang)(wang)出現故障(zhang)(zhang)時電(dian)(dian)(dian)(dian)(dian)(dian)壓會突然降低,發(fa)電(dian)(dian)(dian)(dian)(dian)(dian)機組為了恢(hui)復正常工況(kuang)會向(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)(wang)(wang)(wang)發(fa)出很高的(de)故障(zhang)(zhang)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。國家電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)(wang)(wang)(wang)中某(mou)個區(qu)(qu)域(yu)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)(wang)(wang)(wang)系統(tong)強(qiang)度(du)通常由該地區(qu)(qu)電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)(wang)(wang)(wang)可承受(shou)故障(zhang)(zhang)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)值來判斷。能承受(shou)較高故障(zhang)(zhang)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)區(qu)(qu)域(yu)其(qi)電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)(wang)(wang)(wang)系統(tong)強(qiang)度(du)較高,反之(zhi),其(qi)電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)(wang)(wang)(wang)系統(tong)強(qiang)度(du)就偏弱。
燃(ran)煤、燃(ran)氣或(huo)水力電(dian)(dian)站使用渦輪(lun)機(ji)械帶動同步(bu)發(fa)(fa)電(dian)(dian)機(ji)組發(fa)(fa)電(dian)(dian),由(you)于旋轉(zhuan)部件的(de)(de)慣(guan)性(xing)作(zuo)用,其起(qi)停機(ji)需要一定的(de)(de)時(shi)間(jian),該起(qi)停機(ji)時(shi)間(jian)間(jian)隔(ge)正(zheng)好(hao)讓機(ji)組能(neng)在電(dian)(dian)網(wang)故障瞬(shun)間(jian)保持正(zheng)常運轉(zhuan),為電(dian)(dian)網(wang)正(zheng)常工況(kuang)和故障工況(kuang)切(qie)換提供(gong)緩(huan)沖(chong)(chong)和支撐(cheng)(cheng)作(zuo)用。這(zhe)種緩(huan)沖(chong)(chong)和支撐(cheng)(cheng)作(zuo)用稱為電(dian)(dian)力系統的(de)(de)慣(guan)量。以(yi)風電(dian)(dian)和光伏為主的(de)(de)可再生能(neng)源(yuan)發(fa)(fa)電(dian)(dian)機(ji)組通(tong)常由(you)電(dian)(dian)力電(dian)(dian)子技術為核心的(de)(de)逆變(bian)器構成,由(you)于缺乏旋轉(zhuan)部件帶來的(de)(de)緩(huan)沖(chong)(chong)作(zuo)用,其對(dui)電(dian)(dian)網(wang)瞬(shun)時(shi)故障不能(neng)起(qi)到穩定性(xing)的(de)(de)支持作(zuo)用。
如果一個區域(yu)電網(wang)的(de)同步發電機組相對較(jiao)多,該(gai)區域(yu)電網(wang)往(wang)(wang)往(wang)(wang)能(neng)承(cheng)受(shou)較(jiao)高的(de)故障電流(liu),在各種(zhong)瞬時(shi)電網(wang)故障情況下也能(neng)保持較(jiao)高的(de)穩定(ding)性,該(gai)區域(yu)的(de)電網(wang)強度就會較(jiao)高。
相反,如(ru)果一個(ge)區(qu)域并(bing)(bing)網(wang)機(ji)(ji)組以(yi)電(dian)力電(dian)子(zi)逆(ni)變器技術為(wei)主,并(bing)(bing)且距離大型(xing)同步發電(dian)機(ji)(ji)組較遠,那(nei)么(me)這個(ge)區(qu)域電(dian)網(wang)的強度就會(hui)偏弱。電(dian)網(wang)強度偏低的區(qu)域會(hui)導(dao)致電(dian)網(wang)在(zai)正常(chang)和(he)故障工況切換情況下電(dian)壓波動性(xing)偏高,導(dao)致區(qu)域內逆(ni)變器機(ji)(ji)組停機(ji)(ji)頻率增加,對區(qu)域電(dian)網(wang)的安(an)全(quan)性(xing)和(he)可靠性(xing)造成影響。
輸電邊際損耗系數
在(zai)電(dian)(dian)(dian)力(li)輸(shu)(shu)送(song)過(guo)程(cheng)中(zhong),由于輸(shu)(shu)電(dian)(dian)(dian)線電(dian)(dian)(dian)阻等物理因素會導致(zhi)電(dian)(dian)(dian)力(li)有所(suo)損(sun)(sun)耗(hao)。輸(shu)(shu)電(dian)(dian)(dian)邊際損(sun)(sun)耗(hao)系數(Marginal Loss Factor,MLF)反(fan)映了(le)電(dian)(dian)(dian)力(li)在(zai)電(dian)(dian)(dian)網(wang)系統(tong)輸(shu)(shu)送(song)過(guo)程(cheng)中(zhong)的(de)損(sun)(sun)耗(hao)量。在(zai)輸(shu)(shu)電(dian)(dian)(dian)網(wang)絡中(zhong),部分主要的(de)區(qu)(qu)域(yu)(yu)中(zhong)心點(dian)(dian)(dian)被定義為(wei)區(qu)(qu)域(yu)(yu)參(can)照(zhao)點(dian)(dian)(dian),區(qu)(qu)域(yu)(yu)參(can)照(zhao)點(dian)(dian)(dian)MLF值默(mo)認為(wei)1。某個(ge)發(fa)電(dian)(dian)(dian)項目的(de)MLF值代表1兆(zhao)瓦基數的(de)電(dian)(dian)(dian)力(li)從機(ji)組并(bing)網(wang)點(dian)(dian)(dian)傳(chuan)輸(shu)(shu)到區(qu)(qu)域(yu)(yu)參(can)照(zhao)點(dian)(dian)(dian)產生的(de)損(sun)(sun)耗(hao)水平。MLF的(de)取值因電(dian)(dian)(dian)站位置(zhi)而異,AEMO通(tong)過(guo)向發(fa)電(dian)(dian)(dian)機(ji)組發(fa)出地理位置(zhi)信號,計(ji)算出電(dian)(dian)(dian)站與區(qu)(qu)域(yu)(yu)參(can)照(zhao)點(dian)(dian)(dian)之間的(de)距(ju)離作為(wei)計(ji)算依據。機(ji)組電(dian)(dian)(dian)力(li)從并(bing)網(wang)點(dian)(dian)(dian)傳(chuan)輸(shu)(shu)到區(qu)(qu)域(yu)(yu)參(can)照(zhao)點(dian)(dian)(dian)的(de)損(sun)(sun)耗(hao)越多,AEMO計(ji)算出MLF值越低(di)。相反(fan),傳(chuan)輸(shu)(shu)損(sun)(sun)耗(hao)越低(di),則MLF值較高。
為了(le)便于(yu)國家電(dian)力市場對電(dian)力進行(xing)調(diao)度(du)和(he)結算(suan),并(bing)網(wang)點(dian)的電(dian)價等于(yu)區域電(dian)價乘以其MLF值(zhi)。大型可(ke)再生能源綠證的計算(suan)和(he)認證是(shi)以折(zhe)算(suan)MLF值(zhi)后的發(fa)電(dian)量為計算(suan)基準。因此,MLF值(zhi)不但影(ying)響可(ke)再生能源發(fa)電(dian)企業交易電(dian)量的計算(suan),而且還(huan)影(ying)響其綠證數量的計算(suan)。
每年4月(yue),AEMO會根(gen)據(ju)國家電(dian)(dian)力(li)法(fa)規(gui)要求(qiu)對MLF值進(jin)行重(zhong)新(xin)計(ji)(ji)算(suan)發布,并于當年7月(yue)開始(shi)執(zhi)行。AEMO會綜合考慮(lv)下(xia)(xia)一(yi)財年電(dian)(dian)力(li)需求(qiu)和(he)電(dian)(dian)力(li)調度(du)規(gui)劃,以及電(dian)(dian)力(li)輸送路(lu)徑和(he)輸送電(dian)(dian)力(li)損耗等情況,計(ji)(ji)算(suan)得出下(xia)(xia)一(yi)財年的MLF值。由于MLF的計(ji)(ji)算(suan)受到電(dian)(dian)力(li)輸送路(lu)徑、潮流流向(xiang)等因素影響,如(ru)果(guo)某個(ge)地區短期內新(xin)增很(hen)多電(dian)(dian)站(zhan),將(jiang)(jiang)導致(zhi)電(dian)(dian)力(li)輸送路(lu)徑和(he)調度(du)規(gui)劃改(gai)變,MLF的計(ji)(ji)算(suan)結(jie)果(guo)也將(jiang)(jiang)有(you)所(suo)變化。
建議及應對措施
積極關注(zhu)澳大利亞電(dian)網規劃
2019年以來AEMO和(he)業界各方(fang)進行多輪咨(zi)詢后,于(yu)2020年7月發布(bu)了《國(guo)家(jia)(jia)電網(wang)整合規劃(hua)報告(gao)》。AEMO預測未來20年國(guo)家(jia)(jia)電力市場需要新增(zeng)的(de)(de)各種技(ji)術類型(xing)發電機組規模,結合風(feng)、光資源(yuan)(yuan)分布(bu)情況,擬定了各州最有(you)前景的(de)(de)新能源(yuan)(yuan)發展(zhan)區(qu)域。同時,采用電力系(xi)統模型(xing)和(he)工程分析方(fang)法得出(chu)國(guo)家(jia)(jia)電網(wang)輸電線路系(xi)統升級的(de)(de)需求,為新建(jian)機組提(ti)供(gong)經濟有(you)效(xiao)的(de)(de)市場準入條件,以提(ti)高電力系(xi)統的(de)(de)安全性和(he)可靠性。該報告(gao)展(zhan)現了國(guo)家(jia)(jia)網(wang)絡短期(qi)、中期(qi)和(he)長期(qi)最優化(hua)的(de)(de)發展(zhan)規劃(hua),清晰(xi)描繪了國(guo)家(jia)(jia)電力市場未來20年的(de)(de)發展(zhan)藍(lan)圖(tu)。
投資(zi)人應重(zhong)點參考ISP報告短中期電(dian)網發(fa)(fa)(fa)展規劃,結合AEMO和各州電(dian)網公(gong)司每年發(fa)(fa)(fa)布(bu)的電(dian)網計劃報告,密(mi)切注意(yi)各州電(dian)網升級的發(fa)(fa)(fa)展動態,并(bing)制定(ding)相應的開發(fa)(fa)(fa)和投資(zi)策略。
客觀評估并網風險
澳大利(li)亞可再生能(neng)源(yuan)行業經歷過去幾年的(de)(de)快速擴張,已(yi)經暴露出部分電網基礎設施落后、并網審(shen)批(pi)資源(yuan)不足等(deng)問題,優質并網資源(yuan)更(geng)加(jia)緊俏。當前(qian)多變的(de)(de)市(shi)場環境對投資人(ren)的(de)(de)技術管(guan)理能(neng)力要求更(geng)高,需要投資人(ren)對并網點(dian)風險有更(geng)加(jia)科學和客觀的(de)(de)評估。
從(cong)2018年(nian)(nian)以來,國家電(dian)(dian)(dian)力市場(chang)中可(ke)再(zai)生能(neng)源(yuan)項(xiang)目的(de)MLF值(zhi)呈明顯(xian)的(de)下(xia)降(jiang)趨勢(見(jian)圖3)。AEMO對國家電(dian)(dian)(dian)網(wang)整(zheng)體電(dian)(dian)(dian)網(wang)強(qiang)度在(zai)未來20年(nian)(nian)變(bian)化趨勢進(jin)行預測,其中昆州東南部的(de)電(dian)(dian)(dian)網(wang)強(qiang)度將在(zai)未來5~10年(nian)(nian)出項(xiang)明顯(xian)下(xia)降(jiang),到(dao)了2030年(nian)(nian)左右才會隨著電(dian)(dian)(dian)網(wang)的(de)升級(ji)得到(dao)改(gai)善。
在(zai)項(xiang)目(mu)評(ping)估階段,投資(zi)人需要對(dui)并(bing)網(wang)(wang)(wang)點MLF以及電網(wang)(wang)(wang)擁(yong)堵和(he)限電風險(xian)作出客觀預(yu)測。同(tong)時需要和(he)AEMO核(he)實是否有額(e)外并(bing)網(wang)(wang)(wang)技術要求,是否需要加裝諧波濾波設(she)(she)備、無功補償設(she)(she)備和(he)同(tong)步(bu)調相(xiang)機(ji)等額(e)外設(she)(she)備。如(ru)果并(bing)網(wang)(wang)(wang)報告指出并(bing)網(wang)(wang)(wang)點輸電容量不足或(huo)者電網(wang)(wang)(wang)強度較弱,投資(zi)人需要對(dui)并(bing)網(wang)(wang)(wang)關鍵點進(jin)行專(zhuan)項(xiang)調研評(ping)估,把額(e)外的并(bing)網(wang)(wang)(wang)費(fei)用(yong)納入財務模型中(zhong),確保測算(suan)結果能(neng)滿足預(yu)期收益(yi)率。由于財務測算(suan)結果對(dui)以上假設(she)(she)參數非常敏(min)感,投資(zi)人對(dui)于這些參數取值(zhi)判斷需要盡量保守、客觀和(he)謹慎,在(zai)實質(zhi)投資(zi)前盡可(ke)能(neng)地排除重(zhong)大(da)技術商務風險(xian)。
合理加裝輔助設備
由于輸電(dian)(dian)網(wang)(wang)絡升級(ji)的資(zi)(zi)本(ben)投入(ru)很高,而且需要(yao)(yao)經過(guo)嚴格的投資(zi)(zi)審(shen)批(pi)、環評(ping)和規劃審(shen)批(pi),因此AMEO制定(ding)的中(zhong)短期電(dian)(dian)網(wang)(wang)升級(ji)需要(yao)(yao)5~10年才有可(ke)(ke)能(neng)(neng)完成。在當(dang)前電(dian)(dian)網(wang)(wang)設施升級(ji)相對滯后的情況下,可(ke)(ke)以預見大部分(fen)新(xin)項目并(bing)(bing)(bing)(bing)(bing)(bing)(bing)網(wang)(wang)點(dian)將出現或多或少額外(wai)并(bing)(bing)(bing)(bing)(bing)(bing)(bing)網(wang)(wang)技(ji)術要(yao)(yao)求。如果并(bing)(bing)(bing)(bing)(bing)(bing)(bing)網(wang)(wang)點(dian)電(dian)(dian)網(wang)(wang)強(qiang)(qiang)度(du)(du)較(jiao)弱,并(bing)(bing)(bing)(bing)(bing)(bing)(bing)網(wang)(wang)技(ji)術顧問可(ke)(ke)以在建模時考慮(lv)通(tong)過(guo)調(diao)整優(you)化逆(ni)變器技(ji)術參數來提高并(bing)(bing)(bing)(bing)(bing)(bing)(bing)網(wang)(wang)技(ji)術穩定(ding)性或者(zhe)加裝同步調(diao)相器等輔(fu)助設施來提高電(dian)(dian)網(wang)(wang)強(qiang)(qiang)度(du)(du)以滿(man)足并(bing)(bing)(bing)(bing)(bing)(bing)(bing)網(wang)(wang)技(ji)術要(yao)(yao)求。在當(dang)前并(bing)(bing)(bing)(bing)(bing)(bing)(bing)網(wang)(wang)流(liu)程(cheng)緩慢(man)的情況下,在確保測(ce)算結果能(neng)(neng)滿(man)足預期收益率(lv)的前提下,通(tong)過(guo)主動加裝輔(fu)助設施來滿(man)足并(bing)(bing)(bing)(bing)(bing)(bing)(bing)網(wang)(wang)要(yao)(yao)求,加快(kuai)并(bing)(bing)(bing)(bing)(bing)(bing)(bing)網(wang)(wang)流(liu)程(cheng)進度(du)(du),并(bing)(bing)(bing)(bing)(bing)(bing)(bing)降低未(wei)來受到限(xian)電(dian)(dian)的風險,不(bu)失為一種以退為進的策略。
結語
澳(ao)大(da)利亞國家(jia)電(dian)力(li)市(shi)場(chang)經過20多年(nian)的(de)(de)發展,擁(yong)有健全的(de)(de)電(dian)力(li)法規和監管制度,為各參與方(fang)提供了自由、公平的(de)(de)市(shi)場(chang)環境。隨(sui)著(zhu)澳(ao)大(da)利亞國家(jia)電(dian)力(li)市(shi)場(chang)現貨(huo)電(dian)力(li)交(jiao)易(yi)價(jia)格以及大(da)型綠證價(jia)格在2015~2017年(nian)節節攀升(sheng),澳(ao)大(da)利亞可(ke)再(zai)生(sheng)能(neng)源項目(mu)在2017年(nian)之后(hou)進入了高速增長(chang)期。
為了避免新并(bing)網機組對(dui)國(guo)家電(dian)網帶(dai)來負面沖擊(ji),AEMO對(dui)新的(de)并(bing)網申請將(jiang)采用更嚴格(ge)規范(fan)的(de)技術要求和(he)(he)流程(cheng)管理。愈趨嚴格(ge)的(de)并(bing)網要求體(ti)現出澳大利亞國(guo)家電(dian)力市(shi)場逐漸從相(xiang)對(dui)無序的(de)快速增(zeng)長(chang)期(qi)逐步進入(ru)規范(fan)的(de)穩定增(zeng)長(chang)期(qi)。對(dui)于(yu)投(tou)資(zi)人(ren)來說,一(yi)個項目能(neng)經過嚴格(ge)技術審核,完成并(bing)網流程(cheng)并(bing)成功實現全容量發電(dian),后(hou)續(xu)限(xian)電(dian)等(deng)風險(xian)也會相(xiang)應降低。投(tou)資(zi)人(ren)在(zai)開(kai)發投(tou)資(zi)前期(qi)應采取(qu)科學(xue)有效的(de)方法管控并(bing)網風險(xian),同(tong)時密切關注各州電(dian)網升(sheng)級的(de)發展動態,在(zai)國(guo)家電(dian)力市(shi)場的(de)投(tou)資(zi)做到順(shun)勢而為、有的(de)放矢和(he)(he)事半功倍。
注:本文刊載于《中國電力企業管理》2020年11期,作者供職于中國電建集團海外投資有限公司。