美国能源转型净零路径（英文版）.pdf

Pathways to Net-Zero for the US Energy Transition Jackson Ewing, Martin Ross, Amy Pickle, Robert Stout, and Brian Murray Nicholas Institute for Energy, Environment AVANGRID; Bank of America; bp; the Duke Center for Energy, Development, and the Global Environment; Duke Energy; the Energy Transitions Commission; FedEx; General Motors; Modern Energy; National Grid; Ørsted; RMI; Shell; Volvo Group; and World Resources Institute. Energy Pathways USA is convened by the Nicholas Institute for Energy, Environment necessary progress on project siting, licensing, and materials extraction to develop new energy assets; the need to effectively deploy IRA loan finance and guarantees to bolster equitable investments; the necessity of advancing state and regional coordination, particularly for grid systems; and the current and potential impacts of clean energy standards and carbon pricing for US net-zero prospects. The report seeks to strengthen the evidence base on what will be required for a robust US energy transition, and to elucidate key barriers and pathways toward net-zero goals. It also serves as the foundation for future work by Energy Pathways USA, which will provide in-depth and ongoing analysis across these topics. US EMISSIONS HISTORY AND BUSINESS-AS-USUAL DIRECTION The United States is the world’s largest economy and has been the world’s top energy consumer for much of the post-industrial era, being surpassed by China only in the last 15 years. The US is likewise the single largest national contributor to cumulative global GHG emissions, even before accounting for emissions embodied in imported goods and services. As of 2020, this relative contribution represented 25% of all global CO 2 emissions emitted since the beginning of the industrial revolution (Ritchie 2019). In per capita terms, US energy use is comparatively high, but has declined by 1.8% per year since 2000. The US population has grown while total energy consumption has been remained relatively stable. The Biden administration is proactively pursuing a US energy transition. Using international Paris Agreement pledges as a starting point, the Biden administration has updated the US nationally determined contributions (NDCs) to the agreement with a GHG emissions target of 50% to 52% below 2005 levels by 2030 and economy-wide net-zero emissions “no later than 2050” (The White House 2021a). This is a substantial increase in US ambition, moving from 2015 NDC targets of 26% to 28% reductions below 2005’s levels by 2025 and 80% below 2005 levels by 2050. Business-as-usual (BAU) scenarios, unsurprisingly, do not place the US on track to meet these Paris Agreement climate commitments, or for meeting the Biden administration’s midcentury net-zero ambitions (Figure 1). Figure 2 shows historical trends in overall GHG emissions in the United States since 1990. The six largest categories of CO 2 emissions are those from fossil fuel combustion, which comprised 74.4% of all US GHG emissions as of 2019. The largest—and growing—share is from transportation, at 27.3% of all emissions. Prior to 2010, the electric power sector was the largest source with one- third of all emissions; however, coal plant retirements and a continuing shift to natural gas and renewable generation reduced its share to 24.1% by 2019. These sources are followed by industrial (12.4%) and residential sectors (5.1%), respectively.Nic holas Ins ti tu te for Ene rg y , Environme nt hence the right-hand column for the electricity sector replicates the emissions that have already been included in yellow across the other sectors. By fuel, 45% of CO 2 emissions are associated with consumption of petroleum, mainly in the transportation sector. Natural gas use causes 34% of CO 2 emissions and is split across the industrial, residential, and commercial sectors, where industrial use is the largest component of the total. Most coal is used for electricity generation, aside from a small amount in the industrial sector. Emissions associated with electricity consumption are the largest share of total residential and commercial emissions and represent an important component of industrial emissions. Figure 3. US energy-related CO 2 emissions by sector and fossil fuel in 2021 Source: EIA (2022).Nic holas Ins ti tu te for Ene rg y , Environme nt & S us tainabili t y , Duk e U nive rsi t y | 5 These trends in energy consumption, energy production, and broader characteristics in commerce, housing, and transportation vary widely across the US. Figure 4 ranks US states by energy consumption per capita across the combination of residential, commercial, and transport sectors. In general terms, states with the smallest populations have the highest per capita energy use. This could be attributable to higher transport needs because of more dispersed populations, a hypothesis worth examining in assessing the impacts of national versus regional or local policy interventions. These states are clustered broadly in the middle of the country, with per capita energy consumption declining as the ranking moves toward the East and West Coasts. Residential and commercial use also roughly follows weather patterns measured by heating degree days, with colder states using more energy for heating purposes. Income distributions (not shown) also follow a similar—though inverse—ranking across states, where poorer states are more concentrated in the center of the nation, use more energy per capita, and thus could face higher burdens if emissions reductions cause energy prices to rise. Figure 4 also superimposes industrial energy use per capita (black diamonds) on the ranking of states’ energy consumption in the residential, commercial, and transportation sectors. One of the largest factors influencing these data is the inclusion of energy used in the energy production process, which is categorized as industrial. This explains, for example, why Louisiana, with its petroleum refineries, has industrial energy use that is 6.5 times the national average (it also has a relatively small population when measuring in per capita terms). Texas also has much of the nation’s refining industry and, partly in consequence, has energy use that is more than 2.5 times Figure 4. Ranking US states by energy consumption per capita Source: EIA (2022).