中華民國內政部建築研究所中華民國內政部建築研究所

一、研究緣起
「溫室氣體減量及管理法」自2015年上路以來，明訂我國溫室氣體減量的目標為2050年碳排放減量至2005基準年的50%，爰此我國依六大部門(能源部門、工業部門、運輸部門、農業部門、服務業部門與住宅部門)分別訂立其減碳目標，並於每五年滾動檢討之。由過去之研究發現全國住宅與服務業之溫室氣體排放量占全國總碳排放量約11.69%與9.94%。為達溫管法之目標，各部門暫依各自之全年溫室氣體排放比例分配減碳額度，其中內政部負責住宅部門與服務業部門內建築之溫室氣體減量部分。本計畫係針對我國住商部門溫室氣體排放量推估模式進行比較分析，並基於未來氣象年，結合不確定性分析，同時應用蒙地卡羅方法建立我國住商部門建築之各式與耗能相關之樣態，以作為進行未來住宅與商業部門能源消費分析及預測，並建立溫室氣體排放基線（Business As Usual, BAU）。在建立全國建築溫室氣體排放基線下，進一步提出建築溫室氣體減量經濟誘因機制之建議，期作為政府作為提出住商部門減碳政策之參考。此外我國建築能效標示制度亦已於111年始上路，是建築全年耗能量揭露之重要方法論，亦是未來進行建築節能減碳之重要工具。本計畫另針對「建築能效標示」分析可行之導入方法，評估其潛在的節能(減碳)效益，以作為住商部門節能減碳重要之推行政策參考依據。
二、研究方法及過程
本計畫係針對我國住商部門溫室氣體排放量推估模式之檢討與持續滾動更新推估模式，同時考量未來氣候之變遷、住商未來之成長等因子，進行我國住宅與商業建築能源消耗與碳排放量之分析及預測，除了建立各建築類別之溫室氣體排放基線，並分析我國於未來導入建築能效標示制度後，評估其未來逐年至2050年之預期減碳效益。因此，本計畫之研究目的有以下三點：
1.應用蒙地卡羅方法與不確定性分析，結合未來氣候資料以動態電腦模擬之方式推估住商部門溫室氣體排放量及能源需求量至2050年。
2.因應溫室氣體減量及管理法修正，針對建築溫室氣體減量核發額度及抵減碳費等規定，評估可行之經濟誘因機制之建議。
3.配合淨零建築目標，評估導入建築能效標示制度對我國住商部門之各關鍵年(2030、2040、2050)減碳情境及效益。
三、重要發現
1.依照重新建立之住商碳排基線模型與滾動更新新的各項統計資料後，發現2021年住商部門年總溫室氣體總量為57,986千公噸碳當量，相較於前一年度(2020年)之56,585千公噸碳當量提升了2.4%。因此往後各年之排碳推估基線亦隨之調整，至2025年時預估住商部門之總溫室氣體排放量依發電結構不變與改變下，將分別變為58,512與47,039千公噸碳當量。與現階段所訂的第二階段管制目標至2025年之分配排放額度分別仍有17,091與5,618千公噸碳當量之減碳缺口，尚須進一步分別再減碳29.2%與11.9%。意即排除電力碳排放係數下降所導致之溫室氣體減少量外，額外住商部門本身需再減量11.9%。
2.本研究完成導入建築能效標示制度後未來逐年之減碳效益分析。若依國發會所公布之減碳路徑，在未來能源結構不變之情況，至2050年時之減碳比例4.78%，其溫室氣體排放量減為56,420千公噸CO2，相當於減碳2832.53千公噸CO2，在未來能源結構改變之情況，至2050年時之減碳比例為4.60%其溫室氣體排放量則減為43,394千公噸CO2，相當於減碳2092.40千公噸CO2。
3.本研究同時提出針對建築溫室氣體減量具經濟誘因之推動機制建議。
四、主要建議事項
根據本研究成果發現，提出下列建議：
建議一
本研究顯示在國發會所擬定針對未來新建建築之建築能效提升減碳路徑，由於新建之樓地板面積相較於龐大之既有建築而言相對所佔之比例甚小，在減碳效益上對比於全國住商之全年總溫室氣體排放量而言亦較明顯。有鑑於既存大量的建築效能提升才能有顯著之減碳效果，因此建議評估針對既有建築導入建築能效標示，在擬定不同的減碳路徑下評估其潛在的減碳效益，將更具實質減碳效益，同時作為政策推動方向之參考。
主辦機關：內政部建築研究所
協辦機關：財團法人臺灣建築中心

I.Introduction
The "Greenhouse Gas Reduction and Management Act" was enacted in 2015, specifying that our country's greenhouse gas (GHG) reduction target is to reduce carbon emissions below 50% than that in 2005 by 2050. To this end, the government of Taiwan has set its national carbon reduction targets according to the six major energy consumption sectors, which are constantly reviewed every five years. The GHG emissions from the building and commercial building sectors account for 11.69% and 9.94% of the total carbon emissions nationwide. To allocate the carbon reduction amount among inter-governmental authorities and to evaluate the carbon reduction potential, this research established the business as usual (BAU) estimation model of the future GHG emissions of the nationwide building sectors. The Monte Carlo method and the building energy simulation technique were used to establish the energy consumption profiles of buildings. This research further proposes economic incentives for building GHG reduction as a reference to formulate carbon reduction policies. In addition, the building energy rating system (BERS) is deemed an essential measure to achieve the ultimate net zero emission goal of 2050 for the building sector. The carbon reduction potential of implementing this system was also evaluated in this research.
II.Method
This research reviewed and updated the previously established predicting model of GHG emissions of the building sector in Taiwan. To this end, future climate variation and the growth of the building sectors were both considered to increase the predicting precision of the model. Moreover, the potential carbon reduction of implementing the BERS till the end of 2050 was also appraised. The purposes of this research are as follows:
1.This study applies the Monte Carlo method and uncertainty analysis to combine future climate data with dynamic computer simulation, aiming to estimate GHG emissions and energy demand in the residential and commercial building sectors by 2050.
2.This study proposed feasible economic incentive mechanisms for promoting the nation’s GHG reduction strategy.
3.To achieve the net-zero energy building target, this study evaluates the carbon reduction scenarios and benefits of implementing the BERS for the residential and commercial building sectors in Taiwan in the years 2030, 2040, and 2050.
III.Conclusion
1.After re-calibrating the building sector’s carbon emissions’ BAU model against the newly published national energy consumption inventory data, this study found that the total annual building GHG emissions in 2021 is 57,986 kilotonnes CO2e, which is a 2.4% increment as opposed to that of 2020. Therefore, the baseline of carbon emission projection for the following years will be adjusted accordingly. By 2025, it is estimated that the total building GHGs emissions will be 47,039 kilotonnes CO2e calculated under premises that the equivalent CO2 emission per unit of electricity will be decreased in the future. Excluding the reduction of GHG emissions caused by the removal of electricity carbon emission coefficient, the residential and commercial building sectors need to further reduce by an additional 11.9% of GHGs emissions.
2.This study analyzed the potential carbon reduction benefits after implementing the BERS. If we follow the carbon reduction path announced by the National Development Council, the likely carbon reduction rate will be 4.60% by the end of 2050, which is equivalent to 2092.40 kilotonnes CO2e reduction.
3.This study proposed an implementing mechanism of multiple economic incentive measures to promote the GHG reduction of the building sector.
IV.Suggestion
Based on this study, the amount of GHG reduction from the existing buildings plays a significant role in achieving the ultimate net-zero goal of 2050. It is imperative to further evaluate the potential carbon reduction by implementing the BERS targetted to the existing buildings under various scenarios.
Organizer: Architecture and Building Research Institute, Ministry of the Interior.
Co-organizer: Taiwan Architecture & Building Center