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。
盡管近年來(lai)澳大利亞可(ke)再生(sheng)能(neng)源(yuan)項目(mu)裝(zhuang)機容(rong)量增(zeng)速(su)較快,但國家電網(wang)(wang)(wang)(wang)升級改造速(su)度(du)相對(dui)滯后,引發了(le)例如并(bing)網(wang)(wang)(wang)(wang)申請(qing)期(qi)大幅(fu)度(du)延期(qi)、并(bing)網(wang)(wang)(wang)(wang)技(ji)術要求提高(gao)等與并(bing)網(wang)(wang)(wang)(wang)相關的開(kai)發風(feng)險(xian)。在評(ping)估投(tou)資項目(mu)的過(guo)程中,投(tou)資人除了(le)要開(kai)展對(dui)項目(mu)的發電技(ji)術、土地環評(ping)、規劃審批等常規的盡職調查以外,尤其(qi)要把并(bing)網(wang)(wang)(wang)(wang)風(feng)險(xian)作為首當其(qi)沖(chong)的風(feng)險(xian)要素(su)來(lai)評(ping)估。
澳大利亞國家電網概況
基本特征
澳(ao)大(da)利亞(ya)國(guo)家電(dian)(dian)力(li)市場的(de)(de)電(dian)(dian)網(wang)(wang)系統由昆(kun)士(shi)蘭(lan)州(zhou)(zhou)(zhou)(zhou)(zhou)(zhou)、新南(nan)威(wei)爾士(shi)州(zhou)(zhou)(zhou)(zhou)(zhou)(zhou)(包含首都領(ling)地堪培(pei)拉地區(qu))、維多利亞(ya)州(zhou)(zhou)(zhou)(zhou)(zhou)(zhou)、南(nan)澳(ao)大(da)利亞(ya)州(zhou)(zhou)(zhou)(zhou)(zhou)(zhou)和塔斯(si)馬(ma)尼亞(ya)州(zhou)(zhou)(zhou)(zhou)(zhou)(zhou)的(de)(de)電(dian)(dian)網(wang)(wang)構成,各州(zhou)(zhou)(zhou)(zhou)(zhou)(zhou)電(dian)(dian)網(wang)(wang)通(tong)過(guo)州(zhou)(zhou)(zhou)(zhou)(zhou)(zhou)際(ji)輸(shu)電(dian)(dian)線路(lu)連接,統稱為澳(ao)大(da)利亞(ya)國(guo)家電(dian)(dian)力(li)市場(NEM)。高(gao)壓輸(shu)電(dian)(dian)網(wang)(wang)絡將(jiang)各州(zhou)(zhou)(zhou)(zhou)(zhou)(zhou)大(da)型發電(dian)(dian)機組的(de)(de)電(dian)(dian)力(li)直接傳(chuan)(chuan)輸(shu)到大(da)型工業用戶,同時連通(tong)分布(bu)于(yu)各州(zhou)(zhou)(zhou)(zhou)(zhou)(zhou)的(de)(de)13個(ge)中低壓配電(dian)(dian)網(wang)(wang)絡,將(jiang)電(dian)(dian)力(li)傳(chuan)(chuan)輸(shu)到工商(shang)業以及家庭超過(guo)1千(qian)萬(wan)個(ge)用電(dian)(dian)端客戶。澳(ao)大(da)利亞(ya)國(guo)家電(dian)(dian)網(wang)(wang)跨越總(zong)長度(du)約5000千(qian)米,是世(shi)界(jie)上最長的(de)(de)電(dian)(dian)網(wang)(wang)之一。
澳大(da)利亞(ya)地(di)廣(guang)人稀(xi),人口(kou)主要分布在東南沿海地(di)區,廣(guang)大(da)內陸地(di)區人口(kou)較少(shao),發電(dian)機組和用(yong)電(dian)中心的地(di)理位置相(xiang)對分散,因此,澳大(da)利亞(ya)輸(shu)電(dian)網絡具(ju)有輸(shu)送距離遠、形狀(zhuang)細長及密度較低的物理特征。同(tong)時,由于澳大(da)利亞(ya)中部內陸偏(pian)遠地(di)區的用(yong)戶數(shu)量較少(shao),其電(dian)網設(she)施的規模(mo)和容量也(ye)相(xiang)應較小。
澳(ao)大利亞煤(mei)炭(tan)資源(yuan)豐富,燃(ran)煤(mei)電(dian)站是其主要的電(dian)力來源(yuan)。現(xian)有的大型發電(dian)項目(mu)270多(duo)個(ge),總(zong)裝機(ji)約為55.8吉(ji)瓦(wa)(wa)(wa)。其中燃(ran)煤(mei)電(dian)站裝機(ji)容(rong)量(liang)為23吉(ji)瓦(wa)(wa)(wa),占41.3%;燃(ran)氣電(dian)站裝機(ji)容(rong)量(liang)為12.4吉(ji)瓦(wa)(wa)(wa),占22.2%;由燃(ran)煤(mei)和燃(ran)氣電(dian)站組成的傳統石化(hua)能源(yuan)占國家電(dian)力市場總(zong)裝機(ji)容(rong)量(liang)的63%以上。由大型水電(dian)、風電(dian)和光(guang)伏電(dian)站構成的可再生能源(yuan)項目(mu)共計19.3吉(ji)瓦(wa)(wa)(wa),占總(zong)裝機(ji)容(rong)量(liang)的34%左(zuo)右(見(jian)圖1)。
近年(nian)來部分燃(ran)煤電(dian)(dian)站(zhan)已接近使用(yong)年(nian)限,由于維護(hu)費(fei)用(yong)高昂且存在安(an)全隱患,部分業(ye)主選擇關停這些電(dian)(dian)站(zhan)。自2014年(nian)以(yi)來,澳大(da)(da)利亞(ya)國家電(dian)(dian)力市場已有(you)約(yue)4153兆瓦(wa)燃(ran)煤電(dian)(dian)站(zhan)被關閉,同(tong)期新(xin)增了約(yue)7722兆瓦(wa)水電(dian)(dian)、風電(dian)(dian)和光伏等大(da)(da)型可再(zai)生能源(yuan)(yuan)發電(dian)(dian)項目(mu)(見圖2)。這些數據表(biao)明,澳大(da)(da)利亞(ya)能源(yuan)(yuan)市場的電(dian)(dian)源(yuan)(yuan)供應開(kai)始從(cong)傳統能源(yuan)(yuan)逐漸過渡到以(yi)可再(zai)生能源(yuan)(yuan)為代表(biao)的新(xin)能源(yuan)(yuan)技(ji)術(shu)。
據AEMO預測(ce),從(cong)2020~2040年(nian),還(huan)將有15吉瓦的燃煤電(dian)站達到設計(ji)壽命并將被關閉。這些規(gui)劃(hua)退役的燃煤電(dian)站年(nian)發電(dian)量(liang)共計(ji)約700億千瓦時(shi),占國家電(dian)力市場總用(yong)電(dian)量(liang)的1/3。
并網要求
AEMO是管(guan)(guan)理(li)國家(jia)電力(li)(li)市(shi)(shi)場(chang)(chang)的(de)核心機構,其主(zhu)要職責包(bao)括管(guan)(guan)理(li)電力(li)(li)市(shi)(shi)場(chang)(chang)交(jiao)易主(zhu)體的(de)電力(li)(li)調(diao)度(du)與(yu)交(jiao)易、發(fa)電項目(mu)注冊(ce)與(yu)退出、對(dui)電力(li)(li)市(shi)(shi)場(chang)(chang)的(de)供需進行預測(ce)與(yu)發(fa)布(bu)、管(guan)(guan)理(li)現貨(huo)和輔助服務等市(shi)(shi)場(chang)(chang)的(de)運行、確保電力(li)(li)系統的(de)安全性與(yu)可(ke)靠性等。AEMO運營管(guan)(guan)理(li)主(zhu)要重點考(kao)慮(lv)以下幾(ji)個方面要求:
電(dian)(dian)(dian)(dian)力(li)系(xi)統安全性。電(dian)(dian)(dian)(dian)力(li)系(xi)統的安全性是指(zhi)電(dian)(dian)(dian)(dian)力(li)系(xi)統按照既定的技(ji)術標準,在某些(xie)大型(xing)發電(dian)(dian)(dian)(dian)機(ji)組或(huo)者輸電(dian)(dian)(dian)(dian)線路等主要(yao)系(xi)統組成部分失效的情況下,仍然能正常運行并持續供電(dian)(dian)(dian)(dian)的能力(li)。在電(dian)(dian)(dian)(dian)網(wang)出現臨(lin)時故障(zhang)時,AEMO需采取必要(yao)措施(shi)確(que)保故障(zhang)不(bu)會對電(dian)(dian)(dian)(dian)網(wang)基礎設施(shi)造成嚴重過載或(huo)者損壞(huai)。
電(dian)(dian)力(li)系(xi)(xi)統(tong)可靠(kao)性(xing)。電(dian)(dian)力(li)系(xi)(xi)統(tong)的可靠(kao)性(xing)是(shi)指供(gong)電(dian)(dian)系(xi)(xi)統(tong)在扣(kou)除電(dian)(dian)網(wang)各個環(huan)節的電(dian)(dian)力(li)損(sun)耗后(hou),還能(neng)持續向用(yong)戶端提供(gong)足(zu)夠電(dian)(dian)力(li)以(yi)滿(man)足(zu)客戶用(yong)電(dian)(dian)需(xu)求,電(dian)(dian)力(li)的供(gong)需(xu)達到實時動態平衡。如果供(gong)電(dian)(dian)量不(bu)能(neng)滿(man)足(zu)用(yong)電(dian)(dian)需(xu)求量,兩(liang)者(zhe)之間的差額稱之為電(dian)(dian)力(li)缺口。國家電(dian)(dian)力(li)市場的可靠(kao)性(xing)標準(zhun)規定,每個區(qu)域每年(nian)的電(dian)(dian)力(li)缺口不(bu)能(neng)超過該區(qu)域當年(nian)用(yong)電(dian)(dian)量的0.002%。
電(dian)(dian)(dian)力(li)(li)(li)(li)系統維護。在(zai)電(dian)(dian)(dian)力(li)(li)(li)(li)系統出現故障導致電(dian)(dian)(dian)力(li)(li)(li)(li)供(gong)應不足(zu)的情(qing)況(kuang)下,AEMO有(you)權向尚有(you)儲備(bei)功(gong)率的機組發布行(xing)政指(zhi)令,強制(zhi)其增發電(dian)(dian)(dian)力(li)(li)(li)(li)來彌補(bu)當前的電(dian)(dian)(dian)力(li)(li)(li)(li)缺口。在(zai)采取了(le)各(ge)種調度手段后,如果(guo)仍然不能滿足(zu)某(mou)個(ge)地區(qu)的用電(dian)(dian)(dian)需(xu)求,AEMO有(you)權向電(dian)(dian)(dian)網(wang)公司發布減載行(xing)政指(zhi)令,關停或者下調部分客戶(hu)負載用電(dian)(dian)(dian)量,使電(dian)(dian)(dian)力(li)(li)(li)(li)系統恢復供(gong)需(xu)平(ping)衡。
并(bing)(bing)網(wang)(wang)申(shen)(shen)(shen)請(qing)管理。國家電(dian)力市場(chang)的(de)并(bing)(bing)網(wang)(wang)申(shen)(shen)(shen)請(qing)流(liu)程(cheng)由(you)AEMO配合當(dang)地電(dian)網(wang)(wang)公(gong)司(si)聯合完(wan)成。并(bing)(bing)網(wang)(wang)技(ji)術(shu)審核則(ze)統一(yi)由(you)AEMO來按照(zhao)國家電(dian)力法規相關技(ji)術(shu)要(yao)求(qiu)(qiu)來主導完(wan)成。并(bing)(bing)網(wang)(wang)申(shen)(shen)(shen)請(qing)單(dan)位可以(yi)直(zhi)接(jie)對接(jie)AEMO和項目所(suo)在(zai)州的(de)電(dian)網(wang)(wang)公(gong)司(si)。只要(yao)并(bing)(bing)網(wang)(wang)點有足夠并(bing)(bing)網(wang)(wang)容量(liang)(或(huo)者通(tong)過升(sheng)級滿足容量(liang)要(yao)求(qiu)(qiu))以(yi)及滿足AEMO的(de)并(bing)(bing)網(wang)(wang)技(ji)術(shu)標準(zhun),申(shen)(shen)(shen)請(qing)單(dan)位均(jun)獲(huo)得平等機會完(wan)成并(bing)(bing)網(wang)(wang)流(liu)程(cheng)獲(huo)得并(bing)(bing)網(wang)(wang)許(xu)可。
突出問題
當前(qian)澳大(da)利亞國(guo)家(jia)電(dian)網(wang)中(zhong)大(da)型(xing)可再生能源發(fa)電(dian)機組以及(ji)小(xiao)型(xing)分布式能源增長迅速,形成數以百萬計的(de)(de)分散并網(wang)點。由于適合大(da)型(xing)光伏(fu)和(he)風(feng)電(dian)項目所需(xu)的(de)(de)風(feng)、光資源和(he)土地基(ji)本處于偏(pian)遠地區,加(jia)之這些地區電(dian)網(wang)設施規(gui)模和(he)容量較小(xiao),隨著風(feng)電(dian)和(he)光伏(fu)發(fa)電(dian)機組大(da)規(gui)模涌現(xian),整個(ge)國(guo)家(jia)電(dian)網(wang)電(dian)力系(xi)統的(de)(de)安全(quan)性和(he)可靠性受到一(yi)定程(cheng)度的(de)(de)影響。
南澳(ao)大利亞州超過50%的(de)(de)發電(dian)量來自(zi)以風電(dian)和(he)光(guang)伏(fu)為主(zhu)的(de)(de)可再(zai)生(sheng)(sheng)能源機(ji)組(zu)。由(you)于(yu)可再(zai)生(sheng)(sheng)能源機(ji)組(zu)發電(dian)具有(you)間(jian)歇性,加上(shang)極端(duan)自(zi)然災害天氣(qi)突發,州內儲(chu)備電(dian)源、峰值燃氣(qi)機(ji)組(zu)還有(you)州際輸電(dian)等調度反應不及時(shi),引發了2016年(nian)9月大停電(dian)等一系列規模較(jiao)大的(de)(de)突發事件。
大量新增的(de)可(ke)再生能源項(xiang)目導致(zhi)國(guo)家電(dian)網(wang)(wang)電(dian)力(li)潮流(liu)流(liu)向(xiang)發生改變,2018年4月(yue),AEMO計算出當年昆州(zhou)北(bei)部(bu)、新州(zhou)西部(bu)等區(qu)域的(de)輸電(dian)邊際損耗系(xi)數(MLF)減少了10%~22%。另外(wai),由于維州(zhou)西北(bei)部(bu)和(he)新州(zhou)西南部(bu)莫雷(lei)河(he)流(liu)域西部(bu)地(di)(di)區(qu)(West Murray)的(de)電(dian)網(wang)(wang)強度較弱,無法接納更多的(de)大型光(guang)伏(fu)(fu)電(dian)站并網(wang)(wang),AEMO宣布(bu)2019年9月(yue)開始對(dui)該地(di)(di)區(qu)5個大型光(guang)伏(fu)(fu)發電(dian)項(xiang)目實(shi)施了為期數月(yue)且高達50%的(de)長(chang)期限電(dian)。為了解決West Murray地(di)(di)區(qu)的(de)電(dian)網(wang)(wang)技(ji)術問題,AEMO動用了幾乎所(suo)有的(de)技(ji)術和(he)行(xing)政資(zi)源,導致(zhi)并網(wang)(wang)申請流(liu)程整體效率大幅下(xia)降,并網(wang)(wang)手續延期成為了當前國(guo)家電(dian)力(li)市(shi)場的(de)常(chang)態。
這些(xie)事件表明澳大(da)(da)利亞國家(jia)電(dian)網基礎設(she)施及技(ji)術(shu)管理、資源水平或(huo)多(duo)或(huo)少制約了可(ke)再生(sheng)能源項目大(da)(da)規模高速發(fa)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)(dian)網系統中某處電(dian)(dian)(dian)纜或變(bian)壓器等達到(dao)其(qi)設計極(ji)限或者(zhe)出現故(gu)障,導致其(qi)無法承載更(geng)多電(dian)(dian)(dian)流,就會(hui)出現輸電(dian)(dian)(dian)阻塞,造成當(dang)地發電(dian)(dian)(dian)機組不能滿功率發電(dian)(dian)(dian),機組也就受到(dao)了限電(dian)(dian)(dian)。
除(chu)了(le)由于突發性(xing)故障引起的(de)短暫限電(dian)(dian)(dian)以外,長期限電(dian)(dian)(dian)主要是因(yin)為(wei)(wei)電(dian)(dian)(dian)網(wang)(wang)(wang)的(de)輸電(dian)(dian)(dian)能力受到(dao)電(dian)(dian)(dian)網(wang)(wang)(wang)部(bu)件(jian)(jian)的(de)物理條件(jian)(jian)限制(zhi)。為(wei)(wei)了(le)維護電(dian)(dian)(dian)網(wang)(wang)(wang)安(an)全性(xing)和(he)可靠(kao)性(xing),電(dian)(dian)(dian)網(wang)(wang)(wang)公司會給電(dian)(dian)(dian)網(wang)(wang)(wang)設(she)施工況(kuang)設(she)置安(an)全系數。電(dian)(dian)(dian)網(wang)(wang)(wang)基礎設(she)施在這些物理限制(zhi)和(he)安(an)全設(she)定下,能承載電(dian)(dian)(dian)力的(de)最大值,稱為(wei)(wei)輸電(dian)(dian)(dian)容量限制(zhi)。AEMO和(he)電(dian)(dian)(dian)力公司需把(ba)輸送(song)電(dian)(dian)(dian)力控(kong)制(zhi)在允(yun)許(xu)的(de)輸送(song)容量限制(zhi)范圍內(nei),否則將對(dui)電(dian)(dian)(dian)網(wang)(wang)(wang)設(she)施造成(cheng)損(sun)害,甚至(zhi)導(dao)致電(dian)(dian)(dian)網(wang)(wang)(wang)系統局部(bu)或大規模停電(dian)(dian)(dian)。
解(jie)決(jue)電(dian)網(wang)擁(yong)(yong)堵的根本方法是對(dui)電(dian)網(wang)設(she)施(電(dian)纜(lan)、變(bian)壓(ya)器(qi)以及保護和控制設(she)備(bei)等)進行(xing)升(sheng)級擴容(rong),降(jiang)低(di)電(dian)網(wang)擁(yong)(yong)堵發生的概率,從(cong)而降(jiang)低(di)限(xian)電(dian)風險。但(dan)是對(dui)電(dian)網(wang)升(sheng)級改造(zao)需要大量(liang)的資金(jin)投入和耗(hao)時的行(xing)政審批(pi),如果升(sheng)級改造(zao)電(dian)網(wang)的成(cheng)(cheng)本遠(yuan)超(chao)過限(xian)電(dian)成(cheng)(cheng)本的話,從(cong)短(duan)期來說(shuo),對(dui)發電(dian)單位(wei)限(xian)電(dian)就成(cheng)(cheng)為AEMO不得已而采取的暫時性(xing)措施。
電網系統強度
電(dian)(dian)(dian)(dian)網系(xi)統(tong)強度(du)是(shi)電(dian)(dian)(dian)(dian)力系(xi)統(tong)的固有特性,是(shi)電(dian)(dian)(dian)(dian)網在合理的運行條件下(xia)衡(heng)量(liang)電(dian)(dian)(dian)(dian)力系(xi)統(tong)穩(wen)定性的重要參(can)數之一。當電(dian)(dian)(dian)(dian)網出(chu)現故障時(shi)電(dian)(dian)(dian)(dian)壓會(hui)突然降低,發電(dian)(dian)(dian)(dian)機組為了(le)恢復正(zheng)常工況(kuang)會(hui)向電(dian)(dian)(dian)(dian)網發出(chu)很高(gao)的故障電(dian)(dian)(dian)(dian)流。國家(jia)電(dian)(dian)(dian)(dian)網中某個(ge)區(qu)域的電(dian)(dian)(dian)(dian)網系(xi)統(tong)強度(du)通常由該地區(qu)電(dian)(dian)(dian)(dian)網可承(cheng)受故障電(dian)(dian)(dian)(dian)流值(zhi)來判(pan)斷(duan)。能承(cheng)受較高(gao)故障電(dian)(dian)(dian)(dian)流的區(qu)域其電(dian)(dian)(dian)(dian)網系(xi)統(tong)強度(du)較高(gao),反之,其電(dian)(dian)(dian)(dian)網系(xi)統(tong)強度(du)就偏弱。
燃煤、燃氣或水(shui)力電(dian)(dian)(dian)(dian)站使用(yong)(yong)渦輪機(ji)械帶動(dong)同步發電(dian)(dian)(dian)(dian)機(ji)組(zu)發電(dian)(dian)(dian)(dian),由(you)于旋轉部(bu)件的(de)(de)慣性(xing)作(zuo)用(yong)(yong),其起(qi)停機(ji)需要(yao)一定(ding)的(de)(de)時間,該起(qi)停機(ji)時間間隔正(zheng)好讓(rang)機(ji)組(zu)能在電(dian)(dian)(dian)(dian)網故障(zhang)瞬間保持正(zheng)常運轉,為(wei)電(dian)(dian)(dian)(dian)網正(zheng)常工況(kuang)(kuang)和(he)(he)故障(zhang)工況(kuang)(kuang)切換提供緩(huan)沖(chong)和(he)(he)支(zhi)撐作(zuo)用(yong)(yong)。這(zhe)種(zhong)緩(huan)沖(chong)和(he)(he)支(zhi)撐作(zuo)用(yong)(yong)稱為(wei)電(dian)(dian)(dian)(dian)力系統的(de)(de)慣量。以風電(dian)(dian)(dian)(dian)和(he)(he)光伏為(wei)主的(de)(de)可再生(sheng)能源發電(dian)(dian)(dian)(dian)機(ji)組(zu)通常由(you)電(dian)(dian)(dian)(dian)力電(dian)(dian)(dian)(dian)子技術為(wei)核心的(de)(de)逆變器(qi)構成,由(you)于缺乏旋轉部(bu)件帶來的(de)(de)緩(huan)沖(chong)作(zuo)用(yong)(yong),其對電(dian)(dian)(dian)(dian)網瞬時故障(zhang)不能起(qi)到穩定(ding)性(xing)的(de)(de)支(zhi)持作(zuo)用(yong)(yong)。
如果一個(ge)區(qu)(qu)域電(dian)(dian)網的(de)(de)同步發電(dian)(dian)機組相對(dui)較多,該區(qu)(qu)域電(dian)(dian)網往(wang)往(wang)能承受(shou)較高(gao)的(de)(de)故障電(dian)(dian)流,在各(ge)種瞬時電(dian)(dian)網故障情況(kuang)下也能保持較高(gao)的(de)(de)穩定性,該區(qu)(qu)域的(de)(de)電(dian)(dian)網強度就會(hui)較高(gao)。
相反(fan),如(ru)果一個區域并(bing)網(wang)機組(zu)以電(dian)力電(dian)子逆變器技術為主,并(bing)且(qie)距離大型同步發電(dian)機組(zu)較遠,那么這(zhe)個區域電(dian)網(wang)的(de)強(qiang)度(du)就(jiu)會偏(pian)弱。電(dian)網(wang)強(qiang)度(du)偏(pian)低的(de)區域會導致(zhi)(zhi)電(dian)網(wang)在正常和故障工況切(qie)換情況下(xia)電(dian)壓波動性(xing)(xing)偏(pian)高,導致(zhi)(zhi)區域內逆變器機組(zu)停機頻率增加(jia),對(dui)區域電(dian)網(wang)的(de)安(an)全性(xing)(xing)和可(ke)靠性(xing)(xing)造成影響。
輸電邊際損耗系數
在電(dian)(dian)(dian)(dian)(dian)力輸(shu)送(song)過程(cheng)中(zhong),由于(yu)輸(shu)電(dian)(dian)(dian)(dian)(dian)線電(dian)(dian)(dian)(dian)(dian)阻等物理(li)(li)因素(su)會(hui)導致電(dian)(dian)(dian)(dian)(dian)力有所損(sun)耗(hao)(hao)(hao)(hao)。輸(shu)電(dian)(dian)(dian)(dian)(dian)邊際損(sun)耗(hao)(hao)(hao)(hao)系數(Marginal Loss Factor,MLF)反映了電(dian)(dian)(dian)(dian)(dian)力在電(dian)(dian)(dian)(dian)(dian)網系統輸(shu)送(song)過程(cheng)中(zhong)的(de)(de)損(sun)耗(hao)(hao)(hao)(hao)量。在輸(shu)電(dian)(dian)(dian)(dian)(dian)網絡(luo)中(zhong),部分主要的(de)(de)區域(yu)中(zhong)心點(dian)(dian)被(bei)定義為(wei)區域(yu)參(can)照點(dian)(dian),區域(yu)參(can)照點(dian)(dian)MLF值(zhi)(zhi)默認(ren)為(wei)1。某個發電(dian)(dian)(dian)(dian)(dian)項目的(de)(de)MLF值(zhi)(zhi)代表(biao)1兆瓦(wa)基數的(de)(de)電(dian)(dian)(dian)(dian)(dian)力從機組并網點(dian)(dian)傳(chuan)輸(shu)到區域(yu)參(can)照點(dian)(dian)產生的(de)(de)損(sun)耗(hao)(hao)(hao)(hao)水平。MLF的(de)(de)取值(zhi)(zhi)因電(dian)(dian)(dian)(dian)(dian)站(zhan)位(wei)置而異,AEMO通過向發電(dian)(dian)(dian)(dian)(dian)機組發出(chu)地理(li)(li)位(wei)置信號(hao),計(ji)算(suan)出(chu)電(dian)(dian)(dian)(dian)(dian)站(zhan)與區域(yu)參(can)照點(dian)(dian)之間的(de)(de)距離作為(wei)計(ji)算(suan)依(yi)據(ju)。機組電(dian)(dian)(dian)(dian)(dian)力從并網點(dian)(dian)傳(chuan)輸(shu)到區域(yu)參(can)照點(dian)(dian)的(de)(de)損(sun)耗(hao)(hao)(hao)(hao)越多,AEMO計(ji)算(suan)出(chu)MLF值(zhi)(zhi)越低(di)。相(xiang)反,傳(chuan)輸(shu)損(sun)耗(hao)(hao)(hao)(hao)越低(di),則MLF值(zhi)(zhi)較高(gao)。
為了便于(yu)國家電(dian)(dian)力市場對電(dian)(dian)力進(jin)行調度和結算(suan)(suan),并網點的電(dian)(dian)價等(deng)于(yu)區域(yu)電(dian)(dian)價乘以其MLF值。大型可再(zai)生(sheng)能源(yuan)綠證(zheng)的計(ji)算(suan)(suan)和認證(zheng)是以折算(suan)(suan)MLF值后(hou)的發電(dian)(dian)量(liang)(liang)(liang)為計(ji)算(suan)(suan)基(ji)準。因此,MLF值不但影(ying)響可再(zai)生(sheng)能源(yuan)發電(dian)(dian)企(qi)業(ye)交易(yi)電(dian)(dian)量(liang)(liang)(liang)的計(ji)算(suan)(suan),而(er)且(qie)還(huan)影(ying)響其綠證(zheng)數(shu)量(liang)(liang)(liang)的計(ji)算(suan)(suan)。
每年(nian)4月(yue),AEMO會(hui)根據國家電(dian)力法規(gui)要求對MLF值進行重新計(ji)算發布,并于當年(nian)7月(yue)開(kai)始執行。AEMO會(hui)綜合考(kao)慮下一財年(nian)電(dian)力需求和電(dian)力調度規(gui)劃(hua)(hua),以及電(dian)力輸(shu)送(song)(song)路徑(jing)和輸(shu)送(song)(song)電(dian)力損耗等情(qing)況,計(ji)算得出下一財年(nian)的MLF值。由于MLF的計(ji)算受(shou)到電(dian)力輸(shu)送(song)(song)路徑(jing)、潮流(liu)流(liu)向等因素影(ying)響,如果某個地(di)區(qu)短期內新增很多電(dian)站,將(jiang)導致電(dian)力輸(shu)送(song)(song)路徑(jing)和調度規(gui)劃(hua)(hua)改變(bian),MLF的計(ji)算結果也將(jiang)有所(suo)變(bian)化。
建議及應對措施
積極關注澳大利亞(ya)電網規劃
2019年以來(lai)AEMO和業界各方(fang)進行多輪咨(zi)詢后,于2020年7月發(fa)(fa)布了《國家(jia)電(dian)(dian)(dian)(dian)網整合(he)規(gui)劃(hua)報告(gao)》。AEMO預測未來(lai)20年國家(jia)電(dian)(dian)(dian)(dian)力市場需要新(xin)增的(de)(de)(de)(de)(de)各種(zhong)技術(shu)類(lei)型(xing)發(fa)(fa)電(dian)(dian)(dian)(dian)機(ji)組規(gui)模,結合(he)風、光資源分布情況(kuang),擬定了各州最有(you)前景的(de)(de)(de)(de)(de)新(xin)能源發(fa)(fa)展(zhan)區(qu)域。同時,采用電(dian)(dian)(dian)(dian)力系統(tong)模型(xing)和工程分析方(fang)法得出國家(jia)電(dian)(dian)(dian)(dian)網輸電(dian)(dian)(dian)(dian)線(xian)路系統(tong)升級的(de)(de)(de)(de)(de)需求(qiu),為新(xin)建(jian)機(ji)組提供經(jing)濟(ji)有(you)效的(de)(de)(de)(de)(de)市場準入條件,以提高電(dian)(dian)(dian)(dian)力系統(tong)的(de)(de)(de)(de)(de)安全性和可(ke)靠性。該(gai)報告(gao)展(zhan)現了國家(jia)網絡(luo)短(duan)期、中期和長期最優(you)化的(de)(de)(de)(de)(de)發(fa)(fa)展(zhan)規(gui)劃(hua),清晰(xi)描繪了國家(jia)電(dian)(dian)(dian)(dian)力市場未來(lai)20年的(de)(de)(de)(de)(de)發(fa)(fa)展(zhan)藍圖。
投資人應(ying)重點參考ISP報(bao)告短(duan)中期電網發(fa)展(zhan)規劃,結合AEMO和(he)各州電網公司(si)每年(nian)發(fa)布的電網計劃報(bao)告,密切注意(yi)各州電網升級的發(fa)展(zhan)動態,并(bing)制定(ding)相應(ying)的開發(fa)和(he)投資策略。
客觀評估并網風險
澳大利亞可再生能源(yuan)行(xing)業經歷過去幾年(nian)的(de)(de)快(kuai)速擴張,已經暴(bao)露出(chu)部分電網基礎設施落(luo)后、并(bing)網審(shen)批資(zi)(zi)源(yuan)不足等問題,優質(zhi)并(bing)網資(zi)(zi)源(yuan)更加(jia)緊俏。當前多變的(de)(de)市場(chang)環境對投資(zi)(zi)人的(de)(de)技(ji)術管理能力要(yao)求更高,需要(yao)投資(zi)(zi)人對并(bing)網點風(feng)險有(you)更加(jia)科(ke)學和客觀的(de)(de)評(ping)估。
從2018年(nian)以來(lai)(lai)(lai),國(guo)家(jia)(jia)電(dian)(dian)力市(shi)場中(zhong)可(ke)再生能源項目的(de)MLF值呈明顯(xian)的(de)下降趨(qu)勢(shi)(見圖3)。AEMO對國(guo)家(jia)(jia)電(dian)(dian)網(wang)(wang)整體電(dian)(dian)網(wang)(wang)強度在(zai)未來(lai)(lai)(lai)20年(nian)變化趨(qu)勢(shi)進行預(yu)測,其中(zhong)昆州東南部的(de)電(dian)(dian)網(wang)(wang)強度將在(zai)未來(lai)(lai)(lai)5~10年(nian)出項明顯(xian)下降,到了2030年(nian)左右才會(hui)隨著(zhu)電(dian)(dian)網(wang)(wang)的(de)升級(ji)得到改善(shan)。
在項目評估階段,投(tou)資(zi)人需要(yao)對(dui)(dui)并(bing)(bing)(bing)(bing)網點MLF以及電(dian)網擁堵(du)和(he)限電(dian)風險(xian)作出客觀(guan)(guan)預測(ce)。同時需要(yao)和(he)AEMO核實是(shi)否(fou)有額外(wai)并(bing)(bing)(bing)(bing)網技術(shu)(shu)要(yao)求,是(shi)否(fou)需要(yao)加裝諧波(bo)濾波(bo)設(she)備、無(wu)功補償設(she)備和(he)同步(bu)調相機等額外(wai)設(she)備。如(ru)果并(bing)(bing)(bing)(bing)網報告指出并(bing)(bing)(bing)(bing)網點輸電(dian)容(rong)量不足或(huo)者電(dian)網強度較弱,投(tou)資(zi)人需要(yao)對(dui)(dui)并(bing)(bing)(bing)(bing)網關鍵(jian)點進行(xing)專項調研(yan)評估,把(ba)額外(wai)的并(bing)(bing)(bing)(bing)網費用納入財務模型中,確保測(ce)算結果能滿(man)足預期收益率。由于財務測(ce)算結果對(dui)(dui)以上假設(she)參數非常(chang)敏(min)感(gan),投(tou)資(zi)人對(dui)(dui)于這些參數取(qu)值判斷需要(yao)盡量保守、客觀(guan)(guan)和(he)謹慎(shen),在實質(zhi)投(tou)資(zi)前盡可(ke)能地排除(chu)重大技術(shu)(shu)商務風險(xian)。
合理加裝輔助設備
由于輸電網(wang)(wang)絡升(sheng)級(ji)的(de)資本(ben)投入(ru)很高(gao),而且(qie)需要(yao)經過(guo)嚴(yan)格的(de)投資審批、環評和規劃審批,因此(ci)AMEO制定的(de)中短期電網(wang)(wang)升(sheng)級(ji)需要(yao)5~10年才有可能完成。在當(dang)前電網(wang)(wang)設(she)施升(sheng)級(ji)相對滯后的(de)情況下,可以(yi)(yi)預見(jian)大部分新項目并網(wang)(wang)點將(jiang)出(chu)現(xian)或(huo)多或(huo)少(shao)額外并網(wang)(wang)技(ji)術(shu)要(yao)求(qiu)。如(ru)果(guo)并網(wang)(wang)點電網(wang)(wang)強度較弱,并網(wang)(wang)技(ji)術(shu)顧(gu)問可以(yi)(yi)在建(jian)模時考慮(lv)通過(guo)調(diao)整優化逆變器技(ji)術(shu)參數(shu)來(lai)(lai)提(ti)高(gao)并網(wang)(wang)技(ji)術(shu)穩定性或(huo)者加(jia)裝(zhuang)同步(bu)調(diao)相器等輔助(zhu)設(she)施來(lai)(lai)提(ti)高(gao)電網(wang)(wang)強度以(yi)(yi)滿足(zu)(zu)并網(wang)(wang)技(ji)術(shu)要(yao)求(qiu)。在當(dang)前并網(wang)(wang)流(liu)(liu)程緩(huan)慢的(de)情況下,在確保(bao)測算結果(guo)能滿足(zu)(zu)預期收益率的(de)前提(ti)下,通過(guo)主動加(jia)裝(zhuang)輔助(zhu)設(she)施來(lai)(lai)滿足(zu)(zu)并網(wang)(wang)要(yao)求(qiu),加(jia)快(kuai)并網(wang)(wang)流(liu)(liu)程進度,并降低(di)未來(lai)(lai)受到限電的(de)風(feng)險,不失為(wei)一種以(yi)(yi)退為(wei)進的(de)策略。
結語
澳(ao)大利(li)亞(ya)國家電力(li)市場(chang)經(jing)過20多年的(de)發(fa)展,擁有(you)健全的(de)電力(li)法規(gui)和(he)監管(guan)制度,為各(ge)參與(yu)方提供了(le)自(zi)由、公平的(de)市場(chang)環境。隨(sui)著澳(ao)大利(li)亞(ya)國家電力(li)市場(chang)現(xian)貨電力(li)交(jiao)易(yi)價格(ge)以及大型綠證價格(ge)在2015~2017年節節攀(pan)升,澳(ao)大利(li)亞(ya)可再生能源項目在2017年之后進入(ru)了(le)高速增長期。
為了避免新并(bing)網(wang)(wang)機組對國(guo)家(jia)電(dian)網(wang)(wang)帶來負(fu)面沖擊,AEMO對新的并(bing)網(wang)(wang)申(shen)請將采用(yong)更嚴格(ge)規(gui)范的技術要求和流程管理。愈趨嚴格(ge)的并(bing)網(wang)(wang)要求體現(xian)出澳(ao)大利亞國(guo)家(jia)電(dian)力市(shi)場(chang)逐漸從(cong)相對無序的快速增長期逐步進入規(gui)范的穩定增長期。對于投資(zi)人(ren)來說,一個(ge)項目能經過(guo)嚴格(ge)技術審核,完成并(bing)網(wang)(wang)流程并(bing)成功實現(xian)全(quan)容(rong)量發電(dian),后(hou)續限(xian)電(dian)等風險(xian)也會相應降(jiang)低。投資(zi)人(ren)在(zai)(zai)開發投資(zi)前期應采取科學(xue)有效的方法管控(kong)并(bing)網(wang)(wang)風險(xian),同時密切關注各州電(dian)網(wang)(wang)升(sheng)級的發展動態,在(zai)(zai)國(guo)家(jia)電(dian)力市(shi)場(chang)的投資(zi)做(zuo)到順(shun)勢而(er)為、有的放矢(shi)和事半功倍。
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。