外文翻译---天然气在低碳经济中的角色(编辑修改稿)

外文翻译---天然气在低碳经济中的角色(编辑修改稿)内容摘要：

h the difference due mainly to a steep increase in estimates of recoverable shale gas. Proven reserves have increased 13 percent to 238 tcf, bringing total gas resources to 2,074 tcf. Assessments by ICF International, the . Energy Information Administration (EIA), and Navigant Consulting Inc. confirm the magnitude of this resource. These figures suggest that . supplies of natural gas could last for 90 years at current rates of consumption. And some experts expect the resource estimates to continue rising as exploration proceeds and as extraction techniques are further developed. Since 1990, unconventional gas production has already increased fourfold, with an even steeper rise in the past few years contributing to a sharp decline in gas prices and a collapse in the North American market for imported liquefied natural gas. Surprisingly, the boom has only slowed marginally in the face of a steep recession and a sharp decline in the price of natural gas since 2020, suggesting that unconventional gas may be cheaper to produce than conventional gas. The breakeven price for shale gas in various . basins is reported to range from just under $3 to $ per million BTU. Notably, some of the most recent basins to be tapped, including the Marcellus, are among the least expensive. Moreover, unconventional gas costs are likely to continue to decline since the technology is still relatively immature and is continuing to advance. If these new gas supplies are sufficiently abundant and economical to end the boomandbust cycle that’s marked the industry for decades, gas could make major inroads in energy markets in the years ahead. The rise of gas stands in sharp contrast to the threedecade decline in . oil production. Since 1990, total . gas production has increased 20 percent while oil production fell 33 percent. Today, the United States produces more than twice as much gas as it does oil, and that gap will 山东建筑大学毕业设计 外文文献及译文 6 almost certainly widen in the ing years. After decades of selling their domestic fields to independent producers, major oil panies such as ExxonMobil and BP have signaled a significant shift in their thinking about the future evolution of energy markets by purchasing tens of billions of dollars of gas reserves from those same independents in the past few years. III. Generating LowCarbon Electricity The prospect of more abundant and economical gas supplies, together with the increasing urgency of the climate problem, is drawing increased attention to the role that natural gas might play in the transition to a lowcarbon power sector. In addition to the emissions reductions it offers over coal, natural gas is a more flexible fuel, with the ability to provide backup power on a range of scales to an electricity system that will include a rising share of variable wind and solar energy, bined heatandpower, and distributed generation. Generating electricity from natural gas rather than coal yields dramatic reductions in carbon dioxide emissions. Natural gas contains only half as much carbon per unit of energy as coal does, and gas also lends itself to a more efficient form of power generation known as binedcycle technology. This consists of one or more bustion turbines (similar to jet engines) that are equipped with heatrecovery steam generators to capture heat from the bustion turbine exhaust. The heatrecovery steam generator powers a steamturbine generator to generate additional electric power. Use of the otherwise wasted heat in the turbine exhaust gas results in high thermal efficiency pared to other bustion technologies, yielding efficiencies above 45 percent (pared with 30–35 percent for most coal plants). New binedcycle gas plants produce 55 percent less carbon dioxide than new coal plants do and 62 percent less than the average . coal plant. Although coal is the leading source of electricity in the United States, most of the new power plants added to the . electricity grid since 1990 are powered by natural gas. This includes 201 gigawatts (GW) of highly efficient binedcycle power plants and 107 GW of relatively inefficient gasturbine peaking plants that are typically turned on only when needed during peak demand periods. Altogether, natural gas power plants now represent 31 percent of . generating capacity (excluding gasfired peaking plants, which contribute another 13 percent), pared with 33 percent for coal. Even with the peaking plants excluded, gasfired power generators are underutilized, operating at an average of only 42 percent of their capacity. The carbon emissions of the . power sector could be decreased significantly simply by 山东建筑大学毕业设计 外文文献及译文 7 running some of the existing plants more frequently and operating coal plants less, which would have a significant impact on carbon emissions. In a 2020 study, the Congressional Research Service found that if existing binedcycle plants could be operated at 85 percent of their capacity, gas could replace nearly onethird of coal generation and reduce power sector carbon dioxide emissions by 19 percent. Taking into account transmission and siting constraints, however, the author estimated that the amount of current coal generation that could be displaced by natural gas might be closer to 9 percent. As the disparity in these numbers illustrates, reforming power generation will necessitate a systemic approach to the entire power sector. Besides being more efficient and cleaner than their coal counterparts, binedcycle power plants are also cheaper and quicker to build. A survey of actual fossil, nuclear, and renewable power projects in 2020 determined that natural gas binedcycle plants had the lowest construction costs of any available generating technology, under half the cost of a new pulverized coal plant and just onefifth the estimated cost of a new nuclear plant。