美國2008年能源需求下降,導致與能源相關的二氧化碳排放量,自聯邦政府1990年有年度溫室氣體排放量報告開始,創下最大年度降幅。
據5月20日美國能源部的能源資訊管理局(EIA)的初步估計「2008年下半年創紀錄的高油價加上經濟趨緩,是去年與能源相關的碳排放量減少2.8%的主因。」
EIA報告「與能源相關的碳排放佔全國溫室氣排放量80%以上。2007年至2008年間這類型碳排放從59.67億噸(5,967 MMTCO2)減少到5,802億噸。」
該機構說「就經濟面來看,即便適逢年底經濟衰退,2008年國內生產總值(GDP)仍增長了1.1%。但能源需求卻下降了2.2個百分點。這表示能源密集度--單位GDP能耗,下降了3.3%。」
EIA還估計,「二氧化碳密集度--單位GDP二氧化碳排放量,下跌了約3.8%。」而EIA的數據也顯示,「與石油相關的排放量下降了6%,佔整體能源相關碳排放量降幅的絕大部分。燃煤排放量減少了1.1%,而天然氣排放量則增加了1% ,」
總體能源相關的碳排放量自1990年以來增長了15.9%,一年增加約1個百分點。整體而言,電力部門是美國碳排放最大的單一來源,佔了大約41%的總排放量。
電力部門2008年的排放量減少了2.1%,而發電量卻只減少了1%。EIA說「這1.1%的差異代表2008年風力發電有所成長。」
從1990到2008年,經濟型二氧化碳密集度下降了29.3%,換算成每年1.9%。從最近一年所有溫室氣體的數據顯示,1990到2007年碳密集度下降了26.4%,而每美元GDP溫室氣體總排放量下降了28%。
美國能源資訊署表示,隨著搜集到更多、完整的能源數據,將不斷完善與調整2008年的碳排放量評估。
2008年全國溫室氣排放量盤點結果將在2009年年底公佈,内容包括最新的能源數據,並提供進一步的趨勢分析。
Energy demand across the United States fell in 2008, leading to the largest annual decline in energy-related carbon dioxide emissions since the federal government began annual reporting on greenhouse gas emissions in 1990.
Record-high oil prices and a decline in economic activity in the second half of the year resulted in a decrease of energy-related carbon dioxide emissions of 2.8 percent last year, according to preliminary estimates issued Wednesday by the federal Energy Information Administration.
Energy-related carbon dioxide emissions account for more than 80 percent of U.S. greenhouse gas emissions. These emissions decreased from 5,967 million metric tons of carbon dioxide in 2007 to 5,802 MMTCO2 in 2008, the EIA reported.
The economy, as measured by Gross Domestic Product, GDP, grew by 1.1 percent in 2008, even taking into account the economic downturn at the end of the year, but energy demand declined by 2.2 percent, indicating that energy intensity - energy use per unit of GDP - fell by 3.3 percent in 2008, the agency said.
Carbon dioxide intensity - carbon dioxide emission per unit of GDP - fell by about 3.8 percent, the EIA estimates. Oil-related emissions declined by six percent, accounting for the bulk of overall reduction in energy-related carbon dioxide emissions. Coal emissions decreased by 1.1 percent, while natural gas emissions increased by 1.0 percent, EIA data shows.
Total U.S. energy-related carbon dioxide emissions have grown by 15.9 percent since 1990, about one percent a year. As a whole, the electric power sector is the largest single source of U.S. carbon dioxide emissions, responsible for about 41 percent of total emissions.
In 2008, emissions from the electric power sector decreased by 2.1 percent, while power generation decreased by 1.0 percent. EIA says the decrease in the emissions intensity of generation of 1.1 percent in 2008 reflected an increase in wind-powered generation.
From 1990 to 2008, the carbon dioxide intensity of the economy fell by 29.3 percent or 1.9 percent per year. From 1990 to 2007, the latest year of data for all greenhouse gases, carbon dioxide intensity had fallen by 26.4 percent and emissions of total greenhouse gases per dollar of GDP had fallen by 28.0 percent.
The Energy Information Administration says it will continue to refine its estimates of 2008 carbon dioxide emissions as more complete energy data become available.
A full inventory of all U.S. greenhouse gas emissions in 2008 to be issued in late 2009 will include updated energy data and provide a further analysis of trends.
The preliminary estimates are on EIA's website at: http://www.eia.doe.gov/oiaf/1605/flash/flash.html