國內外城市溫室氣體盤查比較分析

Abstract

溫室氣體減量已成為各城市當前重要的工作之一，國內外不少城市因而進行溫室氣體盤查，唯盤查結果會受參考規範之範疇、計算方式、活動數據選用而有所差異，故不易直接進行比較。故本研究首先進行溫室氣體盤查規劃差異比較，分析參考規範的差異處。然後收集國內外城市的溫室氣體盤查報告，並依各部門分類彙整。發現各部門間盤查方式確實有不少差異，為使各城市間的比較基準較為一致，本研究排除非每個城市都有或佔比較小的項目，重新估算出調整排放量及常排放量，以作為後續分析之依據。 首先比較分析城市特性及溫室氣體影響因子，包括人口密度、就業人數、平均收入、電力排放係數等，天候影響則以Degree days與能源使用量的關係建立國內城市迴歸式，並據以修訂基準。接著比較分析各部門特性及溫室氣體影響因子，工業部門包括能源、從業人口、生產毛額及用水量；住商部門包括能源、商業從業人口、商業生產毛額、用水量、住宅戶數及高層建築比例；交通部門包括道路面積及長度密度、車輛使用量、車輛行駛里程等。依據上述及綜合分析初步結果選用商業從業人口、總人口數、住宅戶數等作為產出項；排放量為投入項，建立指標比較分析各城市常排放量各部門的表現，並據以建立基準公式，分為平均及標竿二種基準，前者為各城市應至少達成的基準，後者為努力的目標，亦藉由此二基準找出標竿城市，供各城市了解其表現離基準的差異，並試著分析出表現不佳的部門及其原因，並初步建議一些改善方案。以供台灣各城市進行溫室氣體減量規劃時之參考依據。

Greenhouse gas (GHG) reduction has become an essential task for cities. Domestic and foreign cities are thus reporting their GHG inventories. However, these inventory reports are difficult to compare directly because of different guidelines, calculation methods, and selections of activity data. Therefore, this study was initiated to develop a method to compare the inventories and analyze their differences for discovering the benchmarks and exemplars in major sectors. GHG Inventory reports from domestic and foreign cities were collected. Inventory information and data were grouped by sector. Various differences were observed for every sectors. Adjusted and common emissions were determined by excluding the emissions from the items that were not commonly reported or had small quantities. Both adjusted and common emissions were used as bases for following benchmark analyses. First, the characteristics of cities and various GHG-related factors, including population density, employed population, average income, and electricity emission factors, were compared and analyzed. The amount of degree days, for analyzing climate effects on energy usages, were calculated, and regressive equations for domestic cites were established and applied to revise the benchmarks for those cities. Then, comparative analyses for each sector for their characteristics and GHG-related factors were implemented. For the industrial sector, its energy usage, employed population, gross production and water usage were analyzed. For the residential and commercial sector, its energy usage, employed population, gross production, water usage, number of households and the ratio for high-rise buildings were compared. For the transportation sector, its road area or length density, number of vehicles, vehicle kilometers traveled were analyzed. According to the results obtained from these comparative analyses and a preliminary aggregative analysis, the commercial employed population, population, number of households were selected as outputs, and the common emission was used as input, to establish indicators for evaluating the performance of major sectors in studied cities. Equations were established for determining the average and benchmark emissions of each city, the former is the typical target should be achieved and the latter is the goal to be pursued. Paradigm cities and sectors were identified based on the average and benchmark emissions. With the average and benchmark emissions and the paragons, how far their gaps to the emissions and paragons of each city were determined and discussed. Sectors with poor performance were also identified and possible policies or actions for reducing GHG emissions were suggested. The results are expected to facilitate the GHG reduction planning for cities in Taiwan.