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1、 1 中國光儲直柔建筑發展戰略路徑研究（二期）Research on the Strategic Path of PEDF Buildings in China(Phase II)子課題 3：農村“光儲直柔”新型電力系統研究 Task 3:Research on the PEDF Power System in Rural Areas 清華大學清華大學 2023 年年 12 月月 15 Tsinghua University Dec 15,2023 致謝致謝 本研究由清華大學統籌撰寫，由能源基金會提供資金支持。ACKNOWLEDGEMENT This report is a product o

2、f Tsinghua University and is funded by Energy Foundation China.免責聲明免責聲明 -若無特別聲明，報告中陳述的觀點僅代表作者個人意見，不代表能源基金會的觀點。能源基金會不保證本報告中信息及數據的準確性，不對任何人使用本報告引起的后果承擔責任。-凡提及某些公司、產品及服務時，并不意味著它們已為能源基金會所認可或推薦，或優于未提及的其他類似公司、產品及服務。Disclaimer-Unless otherwise specified,the views expressed in this report are those of the a

3、uthors and do not necessarily represent the views of Energy Foundation China.Energy Foundation China does not guarantee the accuracy of the information and data included in this report and will not be responsible for any liabilities resulting from or related to using this report by any third party.-

4、The mention of specific companies,products and services does not imply that they are endorsed or recommended by Energy Foundation China in preference to others of a similar nature that are not mentioned.1 執行摘要執行摘要 1.農村能源系統的困境與機遇農村能源系統的困境與機遇-我國農村建筑能耗巨大。我國農村建筑能耗巨大。我國農村地區用能約占全社會建筑能耗的四分之一，農村建筑用能包括 2.2 噸

5、標準煤商品能的使用以及 0.9 億噸的生物質直接燃燒。同時，農村是我國散煤使用率最高的地區，散煤的使用量約 1.1 億噸標準煤。農村建筑運行碳排放約 4.2 億噸，約占全國建筑碳排放的 20%。-我國農村用能造成了高昂的環境代價。我國農村用能造成了高昂的環境代價。由于我國大部分農村主要采用燃燒化石能源的方式滿足自身的用能需求，尤其是北方農村采暖?；茉吹娜紵粌H釋放大量二氧化碳，還會造成嚴重的空氣污染?；茉吹娜紵a物如 PM2.5、氮氧化物、一氧化碳等會嚴重危害室內人員的健康。根據世界衛生組織報告，2019年中國有 103萬人死于空氣污染，其中 62%發生在農村。-農村農村“煤改電，煤改

6、氣煤改電，煤改氣”方案的效果并不理想。方案的效果并不理想。從 2017 年開始，我國開始實施“煤改電，煤改氣”工程，但是由于缺乏合理的頂層設計，天然氣和市政電力的價格過于昂貴，大部分地區的農戶在補貼結束后又用回了散煤。因此，不能把在農村地區實現“碳中和”的任務簡單地理解為一個能源替代工程，而是一個需要詳細可靠的規劃來引導的復雜方案，方案包括科學的技術創新、實際的工程應用、完備的政策引導。這需要在技術、政策、商業模式上進行全面的改革和創新。-農村能源革命與國家戰略息息相關。農村能源革命與國家戰略息息相關。習近平主席在 2020 年的聯合國大會發言中宣布中國“二氧化碳排放力爭于 2030 年前達到

7、峰值，努力爭取2060 年前實現碳中和”。國務院文件強調：脫貧攻堅目標達成后，我國“三農”工作重點向全面推進鄉村振興戰略轉移，農村能源轉型是促進農村產業發展和農村生態治理的主要手段，更是實現鄉村振興戰略的重要基礎。建立農村新型能源系統是實現“碳中和”的必經之路！也是促進農村生態治理、鄉村振興的重要基石。-農村具有發展光伏系統的空間優勢。農村具有發展光伏系統的空間優勢。實現碳中和戰略的主要任務之一是實現從以化石能源為基礎的碳基電力系統轉為以可再生能源為基礎的零碳電力系統。因此，實現農村用能脫碳就要全面推動農戶用能電氣化，并利用可再生能源代替火電。而農村在發展可再生能源有得天獨厚的空間優勢。根據衛

8、星圖像識別的結果，我國農村屋頂面積豐富(130 億)，可安裝 19億 kW光伏，光伏年發電量可達 2.5萬億 kWh，是未來農村實現全面電氣化后所需用電量的 3-4 倍。因此，在農村發展以分布式光伏為核心的新型電力系統可以充分利用農村巨大的光伏潛力，從而使得農村從一個傳統的能源消費者轉變為一個能源的生產者。2.中國農村要建立以屋頂光伏為基礎的新型電力系統中國農村要建立以屋頂光伏為基礎的新型電力系統-傳統的直接逆變上網的方式不能幫助農村實現能源轉型。傳統的直接逆變上網的方式不能幫助農村實現能源轉型。目前農村的光伏系統的運行模式是：開發商租賃農戶的屋頂安裝光伏板，光伏發電直接逆變上網，而農戶依然需

9、要從電網取電滿足自身的用電需求。這樣的光伏系統存在三個問題：1，不公平：變壓器的容量有限，每個村僅少數“捷足先登”的農戶能享受上網容量。這種方式浪費了巨大的農村屋頂光伏潛力；2，不充分：這種系統的發電和用電是兩個體系，開發商獲得了賣電的收益，但是農民無法真正受益。而且，農民沒有享受到光伏電力，這種光伏系統并不能改變農村原有的能源結構；3，不平衡：光伏發電具有隨機性和波動性，直接入網容易產生垃圾電，無法利用農村儲能資源，浪費大量調峰電源資源。因此，現有的光伏系統無法引領農村用能的脫碳化，農村需要一種新的可以讓農民享受光伏電力、為農民帶來真正實惠的電力系統。-農村光儲直柔新型電力系統推動農村能源結

10、構的變革。農村光儲直柔新型電力系統推動農村能源結構的變革。為了克服傳統的農村光伏系統所帶來的不公平、不充分、不平衡的問題，光儲直柔新型電力系統應運而生，它的基本原則是優先自發自用，余電有序上網。該系統的運行方式是：光伏電力優先滿足農戶的用電需求以及儲電設備的充電需求，然后多余的電力響應電網的調度有序地送入電網。與傳統的農村光伏系統相比，這樣的系統有三個優勢：1，變壓器的擴容壓力小，因為相當一部分比例的光伏電力被就地消納了，就可以允許有更多的農戶參與到這個系統中；2，充分利用農村的儲能優勢，使得光伏電力不再是垃圾電，不會增加電網的調度壓力；3，農戶直接使用光伏電力，不僅獲得經濟上的實惠，而且帶動

11、農村全面電氣化以及農村用能脫碳化。圖 I 光儲直柔系統與傳統光伏電力系統的對比 3.農村新型電力系統設計方案農村新型電力系統設計方案-農村新型電力系統的挑戰是解決光伏電力與農戶負荷的不匹配。農村新型電力系統的挑戰是解決光伏電力與農戶負荷的不匹配。光伏電力與農戶用電之間存在嚴重的不匹配，這是農村新型電力系統面臨的最大的挑戰。在逐時的時間尺度上可以看出，由于光伏發電特征與農戶用電特征不一致，導致光伏電力無法始終滿足農戶的用電需求。而解決這個問題的關鍵，是控制策略和儲能技術。儲能可以實現光伏電力的轉移，使得農戶在夜間和陰雨天通過儲能設備的電力就可以滿足自身用電需求。而控制策略決定系統的運行規律，可以

12、使得系統能夠按照預期方案平穩運行。-新型電力系統的拓撲方案需要因地制宜。新型電力系統的拓撲方案需要因地制宜。確定系統拓撲結構是農村新型電力系統設計的基礎。目前農村“光儲直柔”電力系統的拓撲結構大致分為三種。不同的拓撲結構會導致不同的發電效率、傳輸損失、設備容量、控制方法以及投資費用。三種方案各有利弊，因此在實際項目中需要因地制宜，綜合考慮當地的電價、設備成本、上網政策、柔性目標等進行經濟性對比，從而選擇性價比最高的方案。-新型電力系統的設備容量選擇要兼顧可靠性和經濟性。新型電力系統的設備容量選擇要兼顧可靠性和經濟性。選定電力系統設計方案的拓撲結構后，需要確定系統的設備容量，即：光伏裝機容量、儲

13、電容量以及各種變流器的容量。理論上講，光伏容量越大，發電收益越大；儲電容量越大，系統的調控能力越強，柔性潛力也越大。但是在實際工程中，受到成本的限制，系統的設備選擇是一個優化問題，兼顧系統運行可靠性以及經濟性。系統設計容量需要滿足兩個約束條件：（1）多云天氣一天內的光伏發電量不小于農戶的用電量；（2）戶內電池滿足農戶夜間以及陰雨天的用電需求。-新型電力系統需要去中心化的自適應控制方法。新型電力系統需要去中心化的自適應控制方法。由于農村建筑的特征是“量大面散”，傳統的集中控制的方式難以適應農村的場景。對于直流系統，電壓是最簡單也是最重要的運行參數，可以利用電壓信號作為控制信號來改變設備的運行狀況

14、。具體來說，就是系統中的電力電子設備感應接觸點的電壓信號，根據電壓的高低來改變自己的運行狀態。這是一種去中心化無控制器的控制方法，設備根據所在位置的電壓信號做出自適應的調節，維持系統的穩定運行。圖 II 光伏電力與農戶用能的逐時對比 圖 III 常見的農宅光伏拓撲結構 圖 IV 基于母線電壓控制原理 4.農村光伏供暖方案要服務于房間的功能農村光伏供暖方案要服務于房間的功能-對于全天使用的房間需要采用低成本的儲能方案。對于全天使用的房間需要采用低成本的儲能方案。對于臥室這種全天使用的房間，熱負荷穩定，任何時刻都需要供暖。然而光伏電力在夜間以及陰雨天難以滿足房間的供暖需求。因此需要將晴天白天的發熱

15、量轉02000400060008000100000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23Power/WTime/hPV power on sunny daysPV power on cloudy daysRefrigeratorAir conditionerLightCell phone chargingElectric BicycleTVCookiingHot water kettleWashing machineShower 移到夜間以及陰雨天才能與房間熱負荷相匹配，這樣的熱量轉移過程可以通過儲能的方式實現。

16、但是儲電的成本太高，農戶難易承受。而傳統的儲熱技術成本比較昂貴，占地空間大，難以在農宅中實施。因此，可以采用墻體進行儲熱的方式，紅磚價格低廉，同時墻體占地面積小，基本不壓縮農戶的生活空間。供暖末端采用光伏直驅電熱絲的方式，由于電熱絲在運行的過程中不需要控制電壓或者功率的穩定性，因此降低了控制設備的成本。經過測試，房間的冬季黑球平均溫度為 16，滿足農戶的熱舒適需求。-對于間歇使用的房間需要采用低成本的控制策略。對于間歇使用的房間需要采用低成本的控制策略。對于廚房、客廳這樣間歇使用的房間，采用儲熱的方法反而會降低系統控制的靈活性，浪費儲熱資源。因此，采用光伏驅動熱風機的方法對間歇使用的房間進行供

17、暖，因為熱風機系統的升溫速度快，可以快速響應室內人員的變化，適合于間歇使用的房間。然而這樣的系統需要克服光伏電力的波動性從而控制輸出功率和電壓的穩定，在新型電力系統中可以采用電壓信號的控制方法。測試結果顯示，在白天，熱風機的電力幾乎全部來自于光伏電力，而且系統在任何時刻保持輸出功率滿足熱風機的用電需求。圖 V 基于墻體儲熱的光伏供暖系統 5.電動農機將為農村新型電力系統提供儲能資源電動農機將為農村新型電力系統提供儲能資源-農機電氣化是未來農業機械發展的必然趨勢。農機電氣化是未來農業機械發展的必然趨勢。隨著農村全面電氣化的推進，農業機械電氣化將會成為農村潛在的儲電資源，為農村新型電力系統提供調蓄

18、作用。19 世紀 80 年代，世界上開始出現了電動拖拉機，距今為止，電動拖拉機已經過了 130 多年的發展，其發展歷程可以大致 分為電網供電階段與蓄電池供電階段。進入 21 世紀后，隨著能源危機的逐漸加深以及新能源技術的飛速發展，電動拖拉機也迎來了高速發展時期，主要特點如下：集成先進的電力電子技術，進一步提高了電動拖拉機的輕便性和靈敏性；增程式電驅技術的出現提高了電動拖拉機對大功率農田作業的適應性，促進了大功率電動拖拉機的發展；電池技術的極大發展大幅提高了電動拖拉機的額定功率和續航時間。-中國農機電氣化進程還在起步階段。中國農機電氣化進程還在起步階段。我國電動拖拉機的研發起步較晚，直到 196

19、0 年，哈爾濱松江拖拉機廠成功試制了我國首臺電動拖拉機。之后進入發展的相對停滯階段，到 2010 以后，中國的電動農機才迎來井噴式的發展。隨著電動拖拉機動力電池、電驅動技術、整機及部件控制技術以及牽引性、動力性及經濟性等拖拉機使用性能的改善，國內電動拖拉機的研發取得了很大進展，但電動拖拉機實際生產和應用范圍非常有限，電動拖拉機在整機重量、續航時間以及額定功率等性能方面還有較大改善空間。-農機電氣化提供豐富的儲能資源。農機電氣化提供豐富的儲能資源。通過調研不同傳統農機的工作時長和功率范圍，結合目前常用的磷酸鐵鋰電池的參數，對常用農機電氣化的電池容量進行預測。拖拉機械的儲能潛力范圍最大，為 11

20、589kWh，這是由于其作為動力裝置的組合特性決定的。植保機械和耕種機械由于配套使用，整體的儲能潛力相對較大，分別有 0.04 71 kWh 和 8 14 kWh 的儲能潛力。運輸機械的儲能潛力為 6 165 kWh。儲能容量相對小的幾類農機分別為的打藥機、噴霧機、移栽機、牧草機、微耕機以及田園管理機。它們的儲能潛力在 10 kWh 以內，同時在農戶家中較為常見，可基本滿足戶級新型電力系統的儲能調度需求。-電動農機儲能的方式能適應不同的農村場景。電動農機儲能的方式能適應不同的農村場景。對于目前農機戶用使用模式，生產側電動設備如割草機、噴霧機、微耕機等，可提供至少 9 kWh 的儲能潛力。交通側

21、電動設備如電動兩輪車、電動三輪車和低速電動汽車等，該類設備可提供至少 9.5 kWh的儲能潛力。因此，電動農機能為戶級的農村新型能源系統提供至少 20 kWh 的儲能潛力，可滿足農戶的儲能調度的需求。在未來土地規?；洜I的場景下電動農機的情況，大型電動農機的種類將大幅增加，戶用電動農機設備與規?；洜I一方的電動農機設備將通過電池柜及拼裝電池等方式進行有序的充分互動。-農機電氣化將對農村的減碳做出巨大的貢獻。農機電氣化將對農村的減碳做出巨大的貢獻。通過構建一個自上而下的模型對不同規劃情景下農業機械的電氣化帶來碳減排收益進行預測。模型預測在 2025 年農業機械總動力為 113687.7 萬千瓦。

22、僅在市場推動 下，我國電動農機的滲透率發展較為緩慢，2040 年為 26.04%，實現357.81 千噸 CO2的減排收益。在高速發展的情景下，在 2035 年，農業機械電動化帶來 357.81千噸 CO2減排收益，將是市場推動場景下的 5.83倍。積極的政策引導來推廣農機電氣化可以帶來十分可觀的碳減排收益。-農機電氣化的挑戰是電池和電機技術。農機電氣化的挑戰是電池和電機技術。農機電氣化最大的技術難點是電池，電動農機功率大，對運行時長有要求，因此電池要滿足容量大、比能量大的特征。同時農機工作時產生強烈的震動，對電池的安全性和散熱性能的要求也很高。由于工作環境特殊，對電動機性能要求比較高。首先就

23、是要能適應惡劣工作環境，防塵防水可靠性強；其次要有較大的調速范圍滿足不同工況；然后要能承受突變載荷，具有一倍以上過載能力；最后實際使用中具備高轉矩和較高瞬時輸出功率。圖 VI 國內拖拉機發展歷程 圖 VII農機碳排放收益預測模型 圖 VIII農業機械碳排放圖 圖 IX 不同場景下農機電氣化的減碳收益 6.與山東東營羅蓋村達成示范村合作意向與山東東營羅蓋村達成示范村合作意向-羅蓋村具有三大優勢。羅蓋村具有三大優勢。（1）羅蓋村一定程度上代表中國未來的農村場景。面對農村老齡化和空心化的趨勢，合村并居是未來農村的發展路徑之一；（2）無需變壓器擴容費用。羅蓋村已經完成變壓器擴容，村中兩臺變壓器容量將近

24、 1000kW，滿足新型電力系統的需求；（3）當地政府與電網公司的配合度高，也已經和當地電網公司合作申請省科技項目。-示范村新型電力系統方案。示范村新型電力系統方案。每個農宅屋頂安裝 10-15kW 光伏，光伏電力直接送入戶內滿足電器和 5kWh 儲電的需求，多余的電力送入村級母線，滿足集中儲電和周邊地源熱泵機組和農業生產負荷的需求。最后，多余的電力響應電網的調度送入電網。其中，羅蓋村采用電動拖拉機作為集中儲能。20002005201020152020202520302035204003000600090001200015000農業機械碳排放（千噸）年份 傳統場景擬合值 真實值 基準場景 S1

25、 S2 S3 -示范村建設進度。示范村建設進度。目前已申請山東電力科技項目，用于解決項目建設的成本。同時，已經確定了光伏板的投資，示范戶的屋頂光伏鋪設工作已經完成。示范村的設計方案和施工圖紙也已經基本完成。圖 X 羅蓋村衛星影像 圖 XI 羅蓋村新型電力系統拓撲 7.農村新型電力系統的商業模式農村新型電力系統的商業模式-“政府引導，企業投資，農戶參與政府引導，企業投資，農戶參與”的融資方式。的融資方式。新型電力系統共有四家參與方，分別是政府、國家電網、投資開發商、以及農戶。其中，這幾種角色可以相互重疊，一方承擔多個角色。投資主體一般分為農戶個人和企業兩種，農戶作為投資主體來說模式較為簡單，項目

26、建設的復雜度較小，需協調的相關方較少，回收期最短，但是農戶普遍不具備投資能力。相較而言，企業作為投資開發商，運營過程中需要大量協調政府、金融機構的相關關系，投資能力強，但是回收期長。融資的金融機構主要負責建設資本提供和籌集，是整個分布式光伏項目的資金來源渠道，決定著商業模式中資金周轉的有效性，其決定著商業模式是否能正常開展。政府主要負責制定并出臺相關政策、行業發展規范，開展市場監管，批準和發放各類補貼，同時出臺相關的法律對其他的市場主體行為進行約束，化解市場中出現的爭端和沖突，為分布式光伏發展營造良好市場氛圍。-整合政策，集中發力。整合政策，集中發力?，F階段由于市場機制還不完善，導致新型電力系

27、統的經濟性還不具備投資吸引力，這就需要結合政策上的優惠來吸引投資者參與。目前國家對于農村的政策，主要分為四類：1，扶貧政策。如光伏扶貧、旅游扶貧、家政扶貧等；2，基礎設施補貼。如農網升級改造，危房改造；3，專項活動補貼。如清潔取暖、家電下鄉、新能源建設以及農機具購買等；4，生活福利及其他。如農電電費補貼等。因此，農村新型電力系統涉及到多方面的政策補貼，如果多種補貼可以綜合發放，則每個示范戶至少可以獲得 2 萬元的政策優惠，進一步改善農村新型電力系統的經濟性。圖 XII 新型電力系統參與角色分析 8.農村新型電力系統的政策建議農村新型電力系統的政策建議-動態電價是提高參與方積極性的重要動力。動態

28、電價是提高參與方積極性的重要動力。目前限制農村新型電力系統很大的因素是電價，因為電力系統的收益來自于賣電，因此提升電價將會明顯提高電力系統的經濟性。但是，電價與民生直接相關，簡單粗暴地提高電價會影響農戶生活質量。因此，建議采用分時電價，提高非午間上網的電價，這有助于提高儲能經濟性，對于可以靈活響應電網調度的系統是一種正反饋獎勵。同時，降低中午的上網電費和用電電費，引導農戶加大高峰期的用電量，幫助促進光伏的就地消納。同時，也可以在電交易中增加碳交易份額，從而增加可再生能源電力的經濟性。-加大直流變換器、直流電器、電動農機與電動交通工具的補貼。加大直流變換器、直流電器、電動農機與電動交通工具的補貼

29、。直流變換器是造成新型電力系統相比直接逆變系統投資成本更昂貴的主要原因。這就需要出臺相關的政策進行對直流變換器以及直流電器進行補貼。通過對這些直流設備的補貼支持可以提高市場需求，從而促進直流設備的產業升級發展。同樣，對于農村潛在的儲能設備，如電動汽車、電動農機的補貼也對于提高農村新型電力系統的經濟性有積極的作用。需加快各類電動農機具和交通工具電氣化工作，調整對農業裝備的補貼政策，將目前對農林生產機械化方面的各項支持政策轉為支持“油改電”。把農林業裝備電氣化任務納入到我國農林業裝備發展規劃中。采用標準化模塊電池，農機和車輛采用換電模式，可以使蓄電池充分發揮作用。從而全面推動農村新能源系統的建設和

30、農機電氣化的推廣。-加強對農村電力系統上網的監管。加強對農村電力系統上網的監管。以村為單位，將全部農戶屋頂、院子周邊、農業設施、林地荒地具備鋪設光伏的資源統一規劃，“建檔立卡、一村一策”，將電動農機具、電動車、農戶采暖以及家電升級等需求綜合考慮，采用光儲直柔方式，分期分批統一建設。同時，加大對于分布式光伏系統的審查力度，制定光伏并網規范，如嚴格規定儲能比例、系統靈活性、響應速度、自消納率等參數，通過強制的標準提高分布式光伏系統的質量。同時應該在農村引導推廣“優先自發自用，余電有序上網”的系統，逐步淘汰之前的分布式光伏直接逆變上網方案。-建設農村新型電力系統的交易平臺。建設農村新型電力系統的交易

31、平臺。加快分布式發電交易平臺建設，使得投資安裝光伏的農戶可以“隔墻售電”。和城市地區建筑類型多樣、用電計量計費復雜的情形不同，農戶每家天然具備產銷一體的屬性，讓農戶實時感知簡單的清洗電池板、系統別掉線，多余的電就能夠賣錢，除了還貸款還能凈賺一筆錢，可以使得光儲直柔系統的后期運維成本最低?！案魤κ垭姟笨蓮氐灼平猱斍稗r村地區戶用光伏系統中“農戶袖手旁觀、企業運維不起”的困境。Executive Summary 1.Dilemma and Opportunities of Rural Energy Systems-Rural areas in China exhibit significant en

32、ergy consumption in building sector.Energy consumption in rural regions accounts for approximately one-fourth of the total building energy consumption in the entire society.The energy consumption in rural buildings includes the usage of 2.2 million metric tons of standard coal equivalent of commerci

33、al energy and the direct combustion of 90 million metric tons of biomass energy.Additionally,rural areas have the highest utilization rate of bulk coal in China,with an approximate consumption of 110 million metric tons of standard coal.The operational carbon emissions from rural buildings are estim

34、ated to be around 420 million metric tons,representing about 20%of the national building carbon emissions.-The energy consumption in rural areas of China has resulted in significant environmental costs.As a major energy source in rural regions,the combustion of fossil fuels,especially for heating pu

35、rposes in northern rural areas,has led to the release of a large amount of carbon dioxide and severe air pollution.The combustion byproducts of fossil fuels,such as PM2.5,nitrogen oxides,and carbon monoxide,pose serious health risks to indoor occupants.According to a report by the World Health Organ

36、ization,in 2019,approximately 1.03 million people in China died due to air pollution,with 62%of these deaths occurring in rural areas.-The effectiveness of the rural coal-to-electricity and coal-to-gas conversion programs has been less than satisfactory.Since 2017,China has implemented the coal-to-e

37、lectricity and coal-to-gas projects in rural areas.However,due to a lack of comprehensive top-level design,the prices of natural gas and municipal electricity have become excessively high,leading to a situation where many households in most regions have reverted to using bulk coal after the subsidie

38、s ended.Therefore,achieving carbon neutrality in rural areas cannot be simply seen as an energy substitution project but rather as a complex endeavor that requires detailed and reliable planning.This includes scientific technological innovations,practical engineering applications,and comprehensive p

39、olicy guidance.It necessitates comprehensive reforms and innovations in technology,policy,and business models.-The rural energy revolution is closely tied to national strategies.In his speech at the 2020 United Nations General Assembly,President Xi Jinping announced Chinas commitment to peak carbon

40、dioxide emissions before 2030 and strive for carbon neutrality by 2060.A State Council document emphasizes that after achieving poverty alleviation goals,the focus of Chinas rural development shifts towards the comprehensive promotion of rural revitalization strategies.Rural energy transformation is

41、 a key means to promote rural industrial development and ecological governance,and it serves as an important foundation for realizing the rural revitalization strategy.Establishing a new type of energy system in rural areas is a crucial pathway to achieve carbon neutrality and serves as a cornerston

42、e for promoting rural ecological governance and rural revitalization.-Rural areas possess spatial advantages for developing photovoltaic systems.One of the key tasks in achieving carbon neutrality is transitioning from a carbon-based electricity system reliant on fossil fuels to a zero-carbon electr

43、icity system based on renewable energy sources.Therefore,decarbonizing energy consumption in rural areas requires comprehensive promotion of electrification in households and the utilization of renewable energy to replace thermal power generation.Rural areas have unique spatial advantages in develop

44、ing renewable energy sources.According to satellite image recognition results,rural areas in China have abundant roof space,with a potential for installing 1.9 billion kilowatts of photovoltaic capacity.The annual electricity generation from photovoltaic systems can reach 2.5 trillion kilowatt-hours

45、,which is three to four times the projected electricity demand after achieving comprehensive electrification in rural areas.Therefore,the development of a new power system in rural areas,with distributed photovoltaics as a core component,can fully leverage the immense photovoltaic potential in rural

46、 areas,transforming them from traditional energy consumers to energy producers.2.Chinas rural areas are striving to establish a new type of power system based on rooftop PV-The traditional method of direct grid-tied photovoltaic(PV)systems cannot facilitate the energy transition in rural areas.Curre

47、ntly,the operational model of PV systems in rural areas is as follows:developers lease rooftops from households to install PV panels,and the PV-generated electricity is directly fed into the grid,while households still rely on the grid for their electricity needs.This type of PV system faces three m

48、ain issues:Inequity:Due to limited transformer capacity,only a few early adopter households in each village can enjoy grid access.This approach wastes the vast PV potential of rural rooftops.Insufficiency:This system separates electricity generation and consumption into two separate systems.Develope

49、rs gain profits from selling electricity,while farmers do not reap the benefits.Moreover,farmers do not directly benefit from PV electricity,and this type of PV system does not effectively change the existing energy structure in rural areas.Imbalance:PV generation is subject to randomness and fluctu

50、ation,and direct grid integration can lead to the generation of surplus electricity that cannot be effectively utilized.It also fails to leverage rural energy storage resources,resulting in the wastage of a significant amount of peak-shaving power resources.Therefore,the existing PV systems are inca

51、pable of leading the decarbonization of energy consumption in rural areas.Rural areas require a new power system that allows farmers to enjoy PV electricity and brings tangible benefits to them.-The rural“Photovoltaic-Energy storage-DC-Flexible load”power system promotes the transformation of the ru

52、ral energy structure.To overcome the issues of inequity,insufficiency,and imbalance brought by traditional rural PV systems,the“Photovoltaic-Energy storage-DC-Flexible load”power system has emerged.Its fundamental principle is prioritizing self-consumption and orderly grid export of excess electrici

53、ty.The operation of this system is as follows:PV electricity first satisfies the electricity demand of rural households and charges the energy storage devices.Any surplus electricity is then dispatched in an orderly manner to the grid.Compared to traditional rural PV systems,this type of system offe

54、rs three advantages:Reduced pressure for transformer capacity expansion:Since a significant proportion of PV electricity is consumed locally,the pressure for transformer capacity expansion is alleviated,allowing more households to participate in the system.Full utilization of rural energy storage ad

55、vantages:This system leverages rural energy storage capabilities,ensuring that PV electricity is not wasted and does not increase the grids dispatch pressure.Direct utilization of PV electricity by households:Households not only benefit economically from using PV electricity but also drive comprehen

56、sive rural electrification and decarbonization of energy consumption in rural areas.Figure I Comparison between“Photovoltaic-Energy storage-DC-Flexible load”power system and traditional photovoltaic power system 3.Design Scheme for Rural PEDF Power System-The challenge of the rural PEDF power system

57、 lies in addressing the mismatch between PV electricity and household loads.There is a significant mismatch between PV electricity and household electricity demand,which is the biggest challenge faced by the rural PEDF power system.When examined on an hourly time scale,it can be observed that the in

58、consistent characteristics of PV generation and household electricity demand result in PV electricity being unable to consistently meet the needs of households.The key to solving this problem lies in control strategies and energy storage technologies.Energy storage enables the transfer of PV electri

59、city,allowing households to meet their electricity needs during nighttime and cloudy/rainy days through the stored energy.Control strategies determine the operational patterns of the system,ensuring smooth operation according to the intended plan.-The topology of the PEDF power system needs to be ta

60、ilored to local conditions.Determining the systems topology is the foundation of designing a rural PEDF power system.Currently,the topology of rural“Photovoltaic-Energy storage-DC-Flexible load”power systems can be broadly categorized into three types.Different topology options result in varying lev

61、els of generation efficiency,transmission losses,equipment capacity,control methods,and investment costs.Each option has its advantages and disadvantages.Therefore,in practical projects,it is necessary to consider local factors such as electricity prices,equipment costs,grid connection policies,flex

62、ibility goals,etc.,and conduct an economic comparison to select the most cost-effective option.-The PEDF power system requires a decentralized adaptive control method.Due to the characteristics of rural buildings being large in quantity and dispersed in area,traditional centralized control methods a

63、re difficult to adapt to rural scenarios.In the case of a direct current(DC)system,voltage is the simplest and most important operational parameter.The voltage signal can be utilized as a control signal to modify the operating conditions of devices.Specifically,the voltage signal at the sensing cont

64、act of power electronic devices in the system can change their operating state based on the voltage level.This is a decentralized controller-less control method where devices make adaptive adjustments based on the voltage signal at their location to maintain stable system operation.Figure II Hourly

65、comparison of photovoltaic power and energy used by farmers 02000400060008000100000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23Power/WTime/hPV power on sunny daysPV power on cloudy daysRefrigeratorAir conditionerLightCell phone chargingElectric BicycleTVCookiingHot water kettleWashin

66、g machineShower Figure III Common farmhouse photovoltaic topology Figure IV Based on the principle of bus voltage control 4.Rural PV Heating Scheme to Serve Room Functions-A low-cost energy storage solution is needed for rooms that are in use throughout the day.For a bedroom,which is occupied all da

67、y,there is a stable heat load requiring heating at any given moment.However,photovoltaic(PV)power is unable to meet the heating demand of the room during nighttime and cloudy/rainy days.Therefore,it is necessary to transfer the heat generated during sunny days to match the rooms heat load during nig

68、httime and inclement weather.This heat transfer process can be achieved through energy storage.However,the cost of electrical energy storage is prohibitively high and difficult for rural households to afford.Traditional thermal energy storage technologies are expensive and require large amounts of s

69、pace,making them impractical for implementation in rural residences.In this regard,heat storage in walls can be employed as a solution.Red bricks,with their low cost,can serve as a medium for heat storage,while occupying minimal space in the walls,thereby not significantly reducing the living space

70、for households.The heating endpoint can be achieved by using photovoltaic direct-driven electric heating wires.Since the operation of the heating wires does not require voltage or power stability control,it reduces the cost of control equipment.Through testing,it has been determined that the average

71、 black globe temperature in the room during winter reaches 16C,meeting the thermal comfort requirements of rural households.-A low-cost control strategy is required for rooms with intermittent use.For rooms such as the kitchen and living room,which are intermittently used,adopting a thermal storage

72、method would reduce the flexibility of system control and waste thermal storage resources.Therefore,using a photovoltaic-driven heat pump is a suitable approach for heating intermittently used rooms.The rapid temperature rise of the heat pump system allows for quick response to changes in the number

73、 of occupants,making it suitable for such rooms.However,such a system needs to overcome the fluctuations in photovoltaic power in order to control the stability of output power and voltage.In the PEDF power system,a control method utilizing voltage signals can be employed.Test results have shown tha

74、t during the daytime,almost all the power for the heat pump comes from photovoltaic power,and the system maintains output power to meet the electrical demand of the heat pump at all times.Figure V Photovoltaic heating system based on wall heat storage 5.Electric Agricultural Machinery to Provide Ene

75、rgy Storage Resources for Rural PEDF Power Systems-The electrification of agricultural machinery is an inevitable trend for the future development of agricultural mechanization.With the comprehensive electrification of rural areas,the electrification of agricultural machinery will become a potential

76、 energy storage resource,providing regulation and storage capabilities for the new rural power system.In the 1980s,electric tractors began to appear worldwide.Over the past 130 years,electric tractors have gone through two major phases:grid-powered and battery-powered.In the 21st century,with the de

77、epening energy crisis and the rapid development of new energy technologies,electric tractors have entered a period of rapid growth,characterized by the following aspects:Integration of advanced power electronics technology,further improving the lightweight and responsiveness of electric tractors.The

78、 emergence of extended-range electric drive technology has enhanced the adaptability of electric tractors for high-power field operations,promoting the development of high-power electric tractors.Significant advancements in battery technology have greatly increased the rated power and endurance of e

79、lectric tractors.-The process of electrifying agricultural machinery in China is still in its early stages.The development of electric tractors in China started relatively late,and it wasnt until 1960 that the Harbin Songjiang Tractor Factory successfully produced the first electric tractor in the c

80、ountry.Afterward,there was a relatively stagnant period of development.It was only after 2010 that electric agricultural machinery in China experienced a rapid growth phase.With improvements in power batteries,electric drive technology,overall machine,and component control technology,as well as trac

81、tion,power,and economic performance of tractors,significant progress has been made in the research and development of electric tractors in China.However,the actual production and application of electric tractors are still very limited,and there is still considerable room for improvement in areas suc

82、h as overall weight,endurance time,and rated power of electric tractors.-Agricultural machinery electrification provides abundant energy storage resources.By investigating the working duration and power range of different traditional agricultural machines and considering the parameters of commonly u

83、sed lithium iron phosphate batteries,the battery capacity of commonly electrified agricultural machines can be predicted.Tractors have the largest energy storage potential,ranging from 11 to 589 kWh,which is determined by their combined characteristics as power devices.Crop protection machinery and

84、cultivation machinery,due to their complementary use,have relatively large overall energy storage potentials,ranging from 0.04 to 71 kWh and 8 to 14 kWh,respectively.The energy storage potential of transportation machinery is between 6 and 165 kWh.Several types of agricultural machinery,such as spra

85、yers,sprayers,transplanters,forage machines,micro tillers,and garden management machines,have relatively small energy storage capacities,within 10 kWh.However,they are commonly found in rural households and can essentially meet the energy storage scheduling needs of household-level PEDF power system

86、s.-The energy storage methods of electric agricultural machinery can adapt to different rural scenarios.For the current usage patterns of agricultural machinery at the household level,production-side electric equipment such as lawnmowers,sprayers,and micro tillers can provide at least 9 kWh of energ

87、y storage potential.Transportation-side electric equipment such as electric bicycles,electric tricycles,and low-speed electric vehicles can provide at least 9.5 kWh of energy storage potential.Therefore,electric agricultural machinery can provide at least 20 kWh of energy storage potential for house

88、hold-level rural new energy systems,meeting the energy storage scheduling needs of farmers.In the scenario of future large-scale land management,the variety of large-scale electric agricultural machinery will significantly increase.Household-level electric agricultural machinery equipment and the eq

89、uipment used in large-scale operations will interact orderly and extensively through battery cabinets and assembled batteries.-The electrification of agricultural machinery will make a significant contribution to carbon reduction in rural areas.By constructing a top-down model,the carbon emission re

90、duction benefits brought by the electrification of agricultural machinery under different planning scenarios can be predicted.The model predicts that by 2025,the total power of agricultural machinery will be 1,136,877.7 MW.Only with market-driven promotion,the penetration rate of electric agricultur

91、al machinery in China develops relatively slowly,reaching 26.04%by 2040,resulting in a reduction of 357.81 kilotons of CO2 emissions.In the high-speed development scenario,by 2035,the electrification of agricultural machinery will bring a reduction of 357.81 kilotons of CO2 emissions,which is 5.83 t

92、imes higher than the market-driven scenario.Active policy guidance to promote the electrification of agricultural machinery can yield substantial carbon emission reduction benefits.-The challenges of agricultural machinery electrification lie in battery and motor technology.The biggest technical cha

93、llenge in agricultural machinery electrification is the battery.Electric agricultural machinery requires high power and has specific demands for operating duration,thus the battery needs to have a large capacity and high energy density.Additionally,agricultural machinery generates strong vibrations

94、during operation,which imposes high requirements on battery safety and heat dissipation performance.Due to the unique working environment,there are also high demands on the performance of electric motors.Firstly,they need to withstand harsh working conditions and have strong dust and water resistanc

95、e.Secondly,they should have a wide speed range to meet different operating conditions.Thirdly,they should be able to handle sudden load changes and have an overload capacity of more than double the rated load.Lastly,in practical use,they should possess high torque and high instantaneous output power

96、.Figure VI Domestic tractor development history Figure VII Agricultural machinery carbon emission income forecast model Figure VIII Carbon emission map of agricultural machinery Figure IX Carbon reduction benefits of electrification of agricultural machinery under different scenarios 6.Intention to

97、Collaborate with Luogai Village in Dongying,Shandong Province as a Demonstration Village-Luogai Village has three major advantages.(1)Luogai Village represents to a certain extent the future rural scene in China.Facing the trend of aging and hollowing out of the countryside,merging villages and livi

98、ng together is one of the development paths for the future of the countryside.(2)No need for transformer capacity expansion costs:Luogai Village has already completed transformer capacity expansion.The village has two transformers with a combined capacity of nearly 1000 kW,which meets the requiremen

99、ts of the new power system.(3)High cooperation between the local government and the power grid company:Luogai Village represents a future rural living model in China,and there is a high level of cooperation between the local government and the power grid company.-Demonstration Village PEDF Power Sys

100、tem Scheme:Each rural household is equipped with 10-15 kW photovoltaic(PV)panels installed on the rooftops.The PV electricity is directly supplied to meet the households electrical needs and provides 5 kWh of energy storage.Excess electricity is fed into the village-level busbar to meet the demands

101、of centralized energy storage,surrounding ground-source heat pump units,and agricultural production loads.Finally,any surplus electricity is dispatched to the grid in response to grid scheduling.In Luogai Village,an electric tractor is adopted as the centralized energy storage solution.-Progress of

102、the demonstration village construction:Currently,an application has been submitted for the Shandong Electric Power Technology Project to address the construction costs of the project.Additionally,investments for the photovoltaic panels have been secured,and the installation of rooftop PV panels in t

103、he demonstration households has been 20002005201020152020202520302035204003691215AM carbon emissions/MtYear DS predicted value True value MDS LSS MSS HSS completed.The design scheme and construction drawings for the demonstration village have also been largely finalized.Figure X Satellite image of L

104、uogai village Figure XI Topology of the PEDF power system in Luogai Village 7.Business Model for Rural New Power Systems-The government guidance,corporate investment,and farmer participation financing model.The new power system involves four participating parties:the government,the State Grid Corpor

105、ation,investment developers,and farmers.These roles can overlap,with one party taking on multiple roles.The investment entities generally consist of individual farmers and businesses.For farmers,the investment model is relatively simple,with less complexity in project construction and fewer stakehol

106、ders to coordinate with.The payback period is shorter,but farmers generally lack investment capacity.On the other hand,businesses,as investment developers,require extensive coordination with the government and financial institutions during the operational phase.They possess stronger investment capab

107、ility but have a longer payback period.Financial institutions involved in financing primarily provide and raise capital,serving as the funding source for the entire distributed photovoltaic project.They determine the effectiveness of capital turnover in the business model,which in turn affects the n

108、ormal operation of the business model.The governments role primarily involves formulating and implementing relevant policies and industry development standards,conducting market supervision,and approving and distributing various subsidies.Additionally,the government enacts relevant laws to regulate

109、the behavior of other market entities,resolves disputes and conflicts that arise in the market,and creates a favorable market environment for the development of distributed photovoltaics.-Integrating policies and focusing efforts.Currently,due to imperfect market mechanisms,the economic viability of

110、 the new power system lacks investment attractiveness.Therefore,it is necessary to combine policy incentives to attract investors.Currently,the national policies for rural areas can be classified into four categories:(1)poverty alleviation policies,such as photovoltaic poverty alleviation,tourism po

111、verty alleviation,and domestic service poverty alleviation;(2)infrastructure subsidies,including rural grid upgrades and renovation of dilapidated houses;(3)special activity subsidies,such as clean heating,appliance distribution in rural areas,new energy development,and agricultural machinery purcha

112、ses;(4)living welfare and other subsidies,such as electricity tariff subsidies for rural households.Therefore,the rural new power system involves various policy subsidies.If multiple subsidies can be combined and distributed comprehensively,each demonstration household can receive at least 20,000 RM

113、B in policy incentives,further improving the economic viability of the rural new power system.Figure XII New power system participation role analysis 8.Policy Recommendations for Rural PEDF Power Systems-Dynamic electricity pricing is an important incentive to increase the motivation of participants

114、.Currently,a significant constraint on the rural PEDF power system is the electricity price,as the systems revenue comes from selling electricity.Therefore,increasing the electricity price would significantly improve the economic viability of the power system.However,electricity prices are directly

115、linked to peoples livelihoods,and a blunt increase in electricity prices could affect the quality of life for rural households.Therefore,it is recommended to implement time-of-use pricing,with higher prices during non-peak hours.This approach helps improve the economic viability of energy storage an

116、d serves as a positive feedback reward for systems that can flexibly respond to grid dispatch.Simultaneously,reducing the electricity fees during midday and peak consumption periods can encourage rural households to increase their electricity usage during those times,thus facilitating the local abso

117、rption of photovoltaic energy.Additionally,incorporating carbon trading into electricity transactions can enhance the economic viability of renewable energy electricity generation.-Increasing subsidies for DC converters,DC appliances,and electric agricultural machinery and vehicles is essential.DC c

118、onverters are the main reason why the investment cost of the PEDF power system is higher compared to direct inversion systems.Therefore,relevant policies should be introduced to provide subsidies for DC converters and DC appliances.Subsidies for these DC devices can boost market demand and promote t

119、he upgrading and development of the DC equipment industry.Similarly,subsidies for potential energy storage devices in rural areas,such as electric vehicles and electric agricultural machinery,have a positive impact on improving the economic viability of the rural new power system.Efforts should be m

120、ade to accelerate the electrification of various types of electric agricultural machinery and vehicles and adjust the subsidy policies for agricultural equipment to support the transition from fossil fuel-based machinery to electric alternatives.The electrification of agricultural and forestry equip

121、ment should be incorporated into Chinas development plans for agricultural and forestry equipment.The use of standardized modular batteries and adopting a battery-swapping model for agricultural machinery and vehicles can fully utilize the batterys capacity.This will comprehensively promote the cons

122、truction of rural renewable energy systems and the widespread adoption of electric agricultural machinery.-Strengthening the regulation of rural power system grid connection is crucial.The planning of photovoltaic resources should be unified at the village level,considering all households rooftops,s

123、urrounding yards,agricultural facilities,and unused land.A comprehensive approach should be taken,considering the demand for electric agricultural machinery,electric vehicles,household heating,and appliance upgrades.The construction should be carried out in a phased and unified manner,adopting a fle

124、xible approach of integrating solar power generation,energy storage,and grid connection.Additionally,it is important to enhance the scrutiny of distributed photovoltaic systems and establish standards for grid integration.Parameters such as energy storage ratios,system flexibility,response speed,and

125、 self-consumption rates should be strictly regulated.By enforcing these standards,the quality of distributed photovoltaic systems can be improved.Furthermore,it is advisable to guide and promote the system of priority for self-consumption,orderly grid connection of excess electricity in rural areas.

126、This approach gradually phases out the previous practice of direct inversion grid connection for distributed photovoltaic systems.-Establishing a trading platform for the rural PEDF power system is crucial.The development of a distributed generation trading platform should be accelerated,allowing ho

127、useholds that invest in photovoltaics to engage in peer-to-peer electricity sales.Unlike the diverse building types and complex metering and billing systems in urban areas,rural households naturally possess the attribute of integrated production and consumption.By enabling rural households to have r

128、eal-time awareness of simple tasks like cleaning solar panels and system connectivity,they can sell excess electricity and earn additional income,which can offset loan repayments and minimize the long-term operation and maintenance costs of“Photovoltaic-Energy storage-DC-Flexible load”systems.This peer-to-peer electricity trading can effectively address the current challenges of rural household photovoltaic systems,where households are passive and rely on external companies for operation and maintenance.