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應對氣候變化不能靠抑制電力需求

作者: 何國俊 . . . . . . . . .

氣候變化威脅地球食水供應、減少農業生產、危及沿海地區、損害人類健康,並使生態系統惡化。極端天氣造成的過度死亡,更被認為是一大災難性後果。據2017年發表於《科學》(Science)期刊的一篇文章估計,到二十一世紀末,極端氣候帶來的超額死亡成本可能佔美國氣候災難損失總額約70%之多。

決策者的困局

為了應對極端氣候勢將帶來的超額死亡,政策制定者有兩大核心工具可用:一、減緩氣候變化政策(climate change mitigation policy),即通過降低能源的生產和消耗來減少溫室氣體排放。二、適應氣候變化政策(climate change adaptation policy),比如天氣寒冷之際,提供廉價取暖能源;夏季時則在公共場所和家居進一步普及空調等。2016年,《政治經濟學期刊》(Journal of Political Economy)的一篇文章估計,近半個多世紀以來,隨着空調的普及,美國人死於酷熱的風險下降了75%。

然而,若把這兩大政策一併檢視,就會發現一個兩難局面。為了緩解氣候變化,決策者通常認為必須減少能源和電力消耗,很多國家亦採取了相關政策,包括階梯電價(電價隨用電量遞增)、節能補貼和拉閘限電。然而,消耗能源和電力亦是適應極端氣候的必要手段,因此那些抑制能源、電力消耗的政策,可能會帶來意想不到的健康成本。筆者在近期一項研究中,聚焦日本在福島核事故後的大規模節能政策如何影響死亡率,並探討決策者在「適應氣候變化」和「減緩氣候變化」兩大政策目標之間應如何取捨。

可供參考福島核災經驗

日本是一個極度依賴核電的國家,在福島核事故前,全國約30%電力是核電。在核洩漏災難發生以後,由於公眾對核電的恐慌加劇,日本政府逐漸關停所有核電站,結果導致電力嚴重短缺;再者,為了防止大規模停電,在不同地區制定相應的節電目標,鼓勵市民減少用電。由於不同地區對核電站的依賴程度和關閉時段不同,因此節電目標也因地區和時間而異。例如,由福島發電廠供電的東京地區,政府在2011年定下15%的節能目標。相比之下,由於沖繩群島不使用核電,因此並無相應節能目標。

日本節能政策涵蓋各個方面,從而推動了整體社會的廣泛參與。地方政府、公用事業機構、家庭、企業和學校等都有參與政策的實行。鼓勵節電節能的指引由中央政府直接向各方發布,並通過電視頻道、新聞媒體和政府網站進行廣泛宣傳。值得一提的是,由於夏季期間市民使用空調的用電量佔很大部分,為了鼓勵減少使用空調,政府建議盡可能改用風扇;即使必須使用,亦建議將空調溫度維持在攝氏28度。此外,節能措施亦包含鼓勵減少使用其他電子設備,例如將電子馬桶蓋設定為「節能模式」(儘管預計僅能減少1%的家庭用電量)。

雖然上述措施並非強制性,但日本的節能政策成功地改變家庭和個人原有的用電模式。據抽樣調查分析結果顯示,在福島事故發生後的第一個夏季,東京和日本東北地區的空調設定平均溫度從攝氏24.1度上升到26.4度。筆者的研究發現,節能目標較高的地區(如東京),其社會耗電量也會因為更嚴格的節能政策而降幅更大。

日本這次大規模節能政策可視為一次難得的「自然實驗」,以供我們權衡如何在「適應氣候變化」和「減緩氣候變化」兩者之間取捨。從宏觀角度而言,日本能夠大規模減少能源、電力消耗,無疑有助於減緩全球氣候變化。但由於限制了人們適應極端天氣的能力,則可能產生意外的健康成本。

在搜集和分析了日本在2008至2015年間各地區的死亡、天氣、節能目標等資料後,筆者與柏克萊加州大學的合作者Takanao Tanaka在研究中發現,節能政策會加劇極端溫度對死亡率的影響:在節能目標較高的地區,更多人死於極端高溫或低溫。由於日本節能政策主要強調要在夏季節約用電,高溫帶來的死亡風險上升最為明顯。具體來說,我們的測算表明,日本大規模的節能政策造成與高溫相關的死亡風險增加了約3倍,導致每年超過7700人超額死亡。

氣候對策如何取捨

這些研究結果對我國制定氣候變化政策設計和管理有重要啟示。首先,決策者應明白,至少在短期內,氣候減緩政策和減緩氣候變化政策之間存在矛盾。節能政策可以降低未來的氣候災害風險,從而挽救更多未來的生命;然而,即使對於像日本這樣的發達國家,大規模的節能運動也會因為顯著限制個人適應極端氣候事件的能力,而導致當前更多人死亡。筆者認為,決策者應該盡量避免為求減緩未來的氣候變化,就制定現時可能影響市民適應氣候變化的政策。

同樣,其他一些被廣泛接受的節能措施,也會因為同一原因,而造成不可忽視的副作用。這些措施可能包括:階梯電價、拉閘限電、節能補貼、道德規勸(號召減少空調使用的宣傳)等等。近年來,為了實現「碳中和目標」,內地不少城市制定了限制空調使用以及其他能耗的措施,可能會帶來與日本節能政策類似的結果。對比日本,我國很多地區醫療資源還很稀缺,且面對高溫等更加頻繁的氣候災害,如果政策上進一步限制居民的基本能耗需求,不僅可能導致不必要的生產率損失,更可能釀成超額的死亡。

那該如何解決這一困境呢?筆者認為,政策制定者需要把能源電力生產和消耗區分處理,電力需求要少限制,生產則要更清潔。具體來說,在需求方面,政策制定者必須保障並繼續擴大市民的基本能源和電力需求,而不是加以抑制。在供給方面,則應大力推展電力生產結構改革、增加太陽能光伏、風電等綠色能源比重,並配置相應的儲能設施。同時,還要積極推廣和普及高效能生產技術和產品,實現用同額電量以滿足更多需求。

在宏觀層面,氣候變化政策不應該限制市民基本能源、電力消耗,而應該通過大力發展綠色能源來減少發電過程中的碳排放、並降綠色能源成本,讓大眾能更好地適應極端氣候,迎來更舒適的生活。


Source : HKU

Chart: U.S. Electricity Generation

Source : Chartr

Chart: China Electricity Consumption Rose in June 2022

Source : 新华网

Charts: China Electricity Generation Declined YoY in April and May 2022

Source : J Kemp Energy

China Says a Third of Electricity Will Come from Renewables by 2025

China will aim to ensure that its grids source about 33% of power from renewable sources by 2025, up from 28.8% in 2020, the state planning agency said on Wednesday in a new “five-year plan” for the renewable sector.

China’s total renewable energy consumption is set to reach about 1 billion tonnes of standard coal equivalent (TCE) by 2025, as the country bids to raise the share of non-fossil fuels in total energy use to 20%, the National Development and Reform Commission (NDRC) said.

Non-fossil fuels accounted for 15.4% of total primary energy consumption in 2020.

China, the biggest source of climate-warming greenhouse gases, has pledged to raise total wind and solar capacity to 1,200 gigawatts by 2030, almost double the current rate, with plans to build large-scale renewable energy bases in northwestern desert regions.

Climate groups were hoping that China would set a strict energy consumption target for 2025 as it prepares to bring total greenhouse gas emissions to a peak before 2030.

Though China has yet to announce a formal energy cap, the new non-fossil fuel energy consumption figure implies that total primary energy use could reach 5 billion tonnes of standard coal by 2025.

The NDRC said renewables would account for more than half of new energy consumption growth from 2021-2025 period, but China still has leeway to build more fossil fuel-fired power plants over the period as it focuses on improving energy security.

China is aiming to start cutting coal consumption in 2026, but in the meantime could put as much as 150 gigawatts of new coal capacity into operation by then, according to research from the State Grid.


Source : Reuters

Chart: China Overall Electricity Consumption in Q1 2022

From January to March, the electricity consumption of the whole society reached 2,042.3 TWh, a year-on-year increase of 5.0%.

In March, the overall electricity consumption was 694.4 TWh, a year-on-year increase of 3.5%.


Source : China Electricity Council

減碳政策下的中國電力發展

作者: 趙耀華 . . . . . . . . .

專家普遍認為,現時的氣候危機在很大程度上是工業革命的後遺症。工業生產會排放大量溫室氣體暖化地球,如果我們未能將升溫幅度控制在不高於工業革命以前1.5至2攝氏度之內,地球很可能在2100年就不宜人類居住。為此,我們必須在2050年以前將全球碳排放降回至2005年的水平。

造成溫室效應的氣體稱為「溫室氣體」,主要是燃燒化石燃料時所產生的二氧化碳,因此減低碳排放是為地球降溫的主要手段。

2015年的聯合國氣候變化大會(COP21)達成《巴黎協定》,近200個與會國家同意在2050年前達到碳中和的目標。協定中的最重要一環是簽署國家承諾就淨零目標推動國內立法,從而確保全人類在達成這共同目標上的步伐一致。

中國的碳達峰及碳中和政策

在2020年9月22日,國家主席習近平在聯合國大會中向全世界宣布:「中國將提高國家自主貢獻力量,採取更加有力的政策和措施,二氧化碳排放力爭於2030年前達到峰值,努力爭取2060年前實現碳中和。」在去年10月26日,國務院發表《2030年前碳達峰行動方案》,聚焦2030年前碳達峰目標,對推進有關工作列出具體行動。

2030年達到碳達峰,意指每年的二氧化碳排放量會逐年增加至2030年,此後排放量會逐年減少。人類除了懂得排放二氧化碳,也懂得回收二氧化碳(譬如植樹);中國要在2060年達到碳中和,即屆時年度二氧化碳排放量和年度二氧化碳的回收量需要剛好互相抵消。

碳達峰的前景光明抑或黯淡,可說是見仁見智。從今年到2030年底的9年間,要是碳排放以每年2%的速度增長,中國的年度排放量將會較2011年增加19.5%。

由於中國從2020年開始已經成為全世界二氧化碳排放量佔比最高的國家(在2020年就處於30%水平;見【圖1】),在這個基礎上繼續增加排放並非微不足道的事情。

根據國務院這份文件,中國力爭在2060年把全國能源生產中的80%轉為非化學生產能源。到2030年,風力發電和太陽能發電的總產能目標為1200 GW。

筆者認為這些目標並非空中樓閣。根據國家電力局今年初的預測,到年底為止,中國的電力產能會有超過一半為非化石電力。年底全部電力產能估計為2600 GW,非化石電力產能更會達到1300GW!近數十年來中國電力生產各個來源的變化可見【圖2】。

非化石能源供應的不確定性

不過,在新能源發電中,由於核能發電(嚴格來說不算新能源)有其危險性,故不能胡亂擴充;水力發電有賴天然的地理條件而難以人為增長;風力發電和光伏發電固然可作考慮,但兩者都相對不穩定:風力發電產能不穩且丈賴天氣因素。相反,燃煤發電並沒有這些問題,而且供應穩定,其作為輔助燃料的地位難以完全被取代。

中國在去年第四季出現慳電風潮。此前國內實行「市場煤、計劃電」,就是煤價市場化,價格隨市場供求而變,但電力價格則由國家發展和改革委員會(發改委)等官方機構監控。由於全球經濟漸從新冠疫情中復甦,對中國產品需求大增,導致國際煤價急升,中國的煤價亦然。

發電廠由於發電售價受到規管,不能轉嫁成本予用戶,甚至出現虧損。舉例說,全國最大的煤電廠華能國際不僅錄得全年虧損,以每股虧損計算,就超過其過去5年的每股盈利的總和!

煤價在去年下半年急升,發電廠為了避免虧損,寧願「躺平」,所以才會出現家居限電的情況。及後發改委採取了3項措施來應對電廠的龐大虧損:第一,允許基準電價上下浮動20%,高耗能則不設上限;第二,加速批准新煤礦場投產;第三,盡力壓抑煤價,並且規定電廠和煤礦商多採用長期協議來穩定煤價。

如何能保證煤電廠不會嚴重虧損,是確保中國能源供應的重要議題。筆者對發改委上述3項措施有以下意見。

放開電價以保電力供應

筆者認為准許電價浮動是正確的一步,但目前的做法並不徹底。首先電價仍設有上限,即煤電廠仍有可能出現虧損,這會導致兩個問題:第一,電廠可能拉閘限電,影響民生甚至經濟活動;第二,電力價格若能充分反映成本價格,就能提供誘因令消費者減少電力消費(如改用低耗能的電器)。低效能的工廠停產,汰弱留強。現在電力價格設有上限,這種資源調配的功能就失掉了。

目前電價調整並沒有明確的方程式,宜增加其透明度。電力價格應該由兩部分組成,一部分是基本價格,另一部分是燃料調整費。前者可在每年定期估算未來全年原料價格,從而訂定合理價格。後者則根據每月燃料價格的變化,作出機械式的調整;這方面可以參考香港的做法。

無上限增加電費這個可能性,當然不會受市民歡迎。政府可以為生活困難的人士提供支援,更好的做法是安排定額補貼,抵消電價上升的影響。市民可把這些補貼購買電力或進行其他消費。以現金補貼代替專項補貼是更有效率的方法,這是經濟學入門課的內容。

對於政府壓抑煤電價格和簽訂長期協議,筆者認為此舉對壓抑煤炭價格的長遠效用有限,只是權宜之計。

首先,長期協議的價格不能長期偏離現貨價格,現貨價格上升,長期協議的價格也會隨之調整。長期協議的真正作用是提高煤炭供應和價格的透明度,以及減少電力成本的波動性。

若以為去年煤炭價格上升是生產商操控的結果,政府以主動壓抑價格的方式作出干預就可算合理,但筆者並不認為如此,也沒有看到坊間有任何類似的懷疑。既然煤價上升是供求關係的結果,故增加煤炭產量才是正確方向(放開電價也是降低對煤炭的需求,緩解煤價的壓力,不過筆者估計這個作用不會很明顯)。

去年煤價大幅上升,現在仍然在高位,但大幅上升是不是就相等於價格高昂?就等於不合理?如是者,是否就應該干預?筆者並不確定。煤有兩個主要用途:發電(動力煤)和作為冶鋼等工業用途(焦煤)。煤價上升,可淘汰低效率的焦煤用家(如鋼廠、鋁廠)。

由於世界各地經濟在去年逐漸復甦,經濟活動增加,加上補充庫存之需,大大增加了對煤的需求。假以時日,煤價最終會穩定下來,甚至可能大幅度下降,這一切由市場決定。

總括而言,為了應對全球暖化,內地政府已經訂立了2030年達到碳達峰和2060年達到碳中和的目標,以非化石能源來代替化石能源是其中一項重要措施。根據年初的估計,今年底國內的電力產能將有一半為非化石能源(風電、太陽能、核能),但是投資非化石能源需時需錢,而且這些能源供應有其本質上的不確定性,因此在一段很長的時間,煤電依然會是中國電力供應的重要組成部分。保證煤電供應穩定就成為中國能源政策的重中之重。中國在能源發展方面,要貪新不忘舊。在應對全球暖化之餘,北京政府還須着眼於發展新能源車輛。


Source : HKU

重庆首座“零碳”供电所投运

记者: 黄伟 . . . . . . . . .

  记者从国网重庆市电力公司获悉,随着国网重庆城口供电公司庙坝供电所配套充电桩项目日前全面启用,重庆首座光储充用一体化模式的“零碳”供电所建成投运。

  “以前只能在城里充电,现在镇上也有了充电桩,更加方便了。”一大早,重庆市城口县庙坝镇居民彭道林就来到了庙坝供电所旁配套的充电桩设施旁,为自己的电动车充电。

  庙坝供电所地处重庆市城口县西南方,承担着周边469.34平方公里、31个村、1.17万户用户的供电任务。该供电所在原有基础上升级改造后,完成了集光伏、储能、用电设施、充电桩相互协调支撑的源、网、荷、储新型微电网,按照“自发自用、余电上网”模式,实现办公区域绿色用能。

  该项目负责人表示,“零碳”供电所是国网重庆市电力公司打造“渝电特色,国网示范”新型电力系统的一个缩影。国网重庆市电力公司将持续推进重庆市能源绿色低碳转型,助力“双碳”目标实现。()


Source : 新华网

China Deepens Market-oriented Reform for On-grid Price of Coal-fired Power Generation

China’s top economic planner issued a notice on Tuesday to further deepen the market-oriented reform for the on-grid price of coal-fired power generation amid the country’s recent power crunch.

The notice, issued by the National Development and Reform Commission (NDRC), details the implementation of four significant measures for the reform.

NDRC will orderly liberalize the on-grid price of coal-fired power generation, with all coal-fired power entering the market and the on-grid price being formed within the range of “base price plus fluctuation” through market transaction.

Meanwhile, the NDRC announced an expansion of fluctuation limits for the coal-fired power trading price to 20 percent from a previous 10 percent rise and 15 percent fall, but the market transaction price of energy-intensive enterprises is not subject to the 20 percent rise.

Wu Chenhui, an independent industry analyst, told the Global Times that relaxing the power trading price fluctuation range would alleviate the current power crunch to some extent, as it would give electricity companies more leeway to adjust prices in the face of surging coal costs.

“It is also an effective method for targeting companies with excessive power usage by pressing them to use power more efficiently,” Wu noted.

With 70 percent of all electricity generated in China already connected to the electricity market, following the expansion of the fluctuation limit and market mechanism of “base price plus fluctuation,” the trading prices of coal-fired power generation in some local power markets have risen, which has played a positive role in alleviating the operating difficulties of coal-fired power generation companies, Peng Shaozong, an official from NDRC said at a press briefing on Tuesday.

As energy-intensive enterprises are not subject to the 20 percent rise, the measure will help guide energy-intensive enterprises to curb unreasonable power consumption while promoting the transformation and upgrading of the industrial structure of these enterprises, Wan Jinsong, director of NDRC’s Department of Price said on Tuesday.

Equally, the reform may come as a blow to certain companies as they will face increasing operational costs, especially the high energy consuming firms as they are very sensitive to power price changes.

For example, for many aluminum companies, power costs account for nearly 30-50 percent of their operation overheads, while their profit margin is very thin. Therefore, their business will face quite some blow from the power price adjustment, Wu said.

The notice expresses that the NDRC will promote industrial and commercial users to enter the market and cancel the price of electricity sold through industrial and commercial catalogs while maintaining stable electricity prices for residual uses, agriculture, and public welfare programs.

The notice also stressed the importance of implementing measures to ensure successful reform, as NDRC will promote the construction of a sustainable electricity market, strengthen the connection with the peak pricing and off-peak tiered pricing for electricity, while avoiding unreasonable administrative intervention and strengthening oversight of the coal and power market.

Moreover, Peng noted that this reform will not directly affect the country’s consumer price index (CPI) but has a certain boosting effect on the industrial producer price index (PPI), which is conducive to maintain price stability.


Source : National Development and Reform Commission

China’s Electricity Use Hits Fresh Record, Prompting Efforts to Avert shortages

China has experienced its first electricity consumption peak of the summer, with national daily use at a record due to the rapid pace of manufacturing activities and a heat wave across the country. The load of at least 11 provincial-level power grids reached new highs over the past week.

However, despite the surging demand, China has abundant ways to cope, including the government’s trans-regional coordination and high-tech measures such as robot inspection, to ensure power supplies – just as it managed to do over the past decades, analysts and industry players said.

According to a report on Sunday by state broadcaster China Central Television (CCTV), the national daily electricity use set a new record on Wednesday, reaching 27.187 billion kilowatt hours (kWh), up more than 10 percent from the peak last summer.

Electricity consumption also increased more than 4.7 percent compared with the extreme cold wave at the beginning of this year. The heat wave also pushed some of China’s biggest industrial bases’ electricity use to unprecedented levels.

For instance, the power load in East China’s Zhejiang, a major export hub near Shanghai, surpassed 100 million kWh on Tuesday for the first time, making it the third provincial power grid with a load exceeding 100 million kWh following South China’s Guangdong and East China’s Jiangsu.

Amid the record consumption, efforts are also underway to ensure steady supply.

Local workers in Zhejiang are trying to ensure smooth power supplies by using an insulated arm truck robot, which can enable workers to operate on the ground to complete installation work, according to media reports.

The load of the provincial-level power grid in China – equivalent to almost five times the energy produced by China’s largest hydropower station, the Three Gorges – has surpassed that of Germany, the largest industrial country in Europe.

Power demand has mainly been affected by weather factors, compounded by rapid economic development, which caused a significant increase in electricity loads since mid-July – the arrival of the first wave of peaks, Zhu Weijiang, deputy director of the National Electric Power Dispatching Control Center, told CCTV.

In the current peak of consumption, the regional power grids in East China and Central China, as well as 11 provincial-level power grids in Guangdong, Jiangsu, Zhejiang, Anhui, Fujian, Jiangxi, Shaanxi and Guangxi, have all hit record highs, Zhu said.

In order to ensure power during peak periods, the State Grid has stepped up transmission across regions, and the cross-regional power transmission capacity during the peak period exceeded 100 million kilowatts for the first time, added Zhu.

So far, power supply is stable and orderly, which can guarantee that demand is met during the peak summer period, the official said.

Peak electricity demand in China often occurs in July and August due to the heavy use of air conditioners and activity at industrial facilities, Han Xiaoping, chief analyst at energy industry website china5e.com, told the Global Times on Sunday, adding that the heavy electricity use is due to the catch-up growth of factory demand as the manufacturing sector recovers from the COVID-19 epidemic.

Han said that responses to future demand surges may still include asking some factories to curtail electricity use, adding that this is a temporary and common approach used during peak periods.

Media reports have said that factories in Guangdong Province were told by local authorities to curtail their electricity use – for instance, some said they had to stop work for two days a week, which affected their daily production.

However, manufacturers told the Global Times that the situation only occurred once over the past two months, and now their operations are all going smoothly.

“We have not seen any notice asking us to curb electricity use so far, and all is running smoothly,” a factory owner surnamed Zhao in East China’s Jiangsu Province told the Global Times on Sunday.

Zhao’s factory specializes in injection molding, a high electricity-consuming sector.

“Electricity consumption is getting higher and higher as a source of energy. It is estimated that electricity will account for 90 percent of primary energy use in 2060 in China,” Han said.

At present, 60 percent of China’s electricity is generated by fossil fuels, while 40 percent comes from renewable sources, Han said. The growth of renewable energy will also accelerate with China’s clean energy push, according to Han.


Source : Global Times