随着30个州的1.6亿人处于极端温度的警戒之下，美国能源部宣布进入紧急状态，因为热浪袭击了全国大部分电网。
美国能源部长克里斯·赖特发布了能源紧急警报，指示大西洋中部地区最大的电网PJM互联公司的官员采取行动，防止停电，并确保医院等基本业务在热浪期间完全运作。
赖特在周二的一份声明中说:“在PJM服务区维持负担得起、可靠和安全的电力是没有商量余地的。”。
PJM为华盛顿特区和13个州的全部或部分地区的约6500万用户供电，包括特拉华州、密歇根州、马里兰州、肯塔基州、新泽西州、北卡罗来纳州、俄亥俄州、宾夕法尼亚州、田纳西州、弗吉尼亚州和西弗吉尼亚州。
莱特的紧急声明于周二晚上11点59分生效，将持续到周五晚上11点59分，它还指示PJM通过减少对数据中心的供电来节约能源，这些数据中心有备用发电机和其他非紧急设施，这些设施消耗大量电力。
PJM表示，预计周四的电力峰值需求为166，304兆瓦，即消费者一小时的平均总电力需求，这将打破2006年创下的纪录。
危险的热浪给东海岸、中西部和南部带来了长时间的极端高温。
在7月4日假期之前，芝加哥和底特律的高温指数，或高湿度下的温度感觉，预计将飙升至100度，纽约市为110度，费城为112度，华盛顿特区为113度，田纳西州纳什维尔为111度。
休斯顿大学能源和创新副校长Ramanan Krishnamoorti告诉美国广播公司新闻说:“这真的会给电网带来压力。”“我认为，我们将看到不同地理区域的需求峰值将创下纪录。”
运营该州电网的纽约独立系统运营商(NYISO)表示，预计未来几天电力需求也将接近历史最高水平。
覆盖美国中西部和南部15个州的美国中部独立系统运营商(MISO)表示，它也可能打破峰值需求纪录。
“一切都被拉伸到了极限，”Krishnamoorti说。“我认为你会看到需求方面的巨大挑战。”
更糟糕的是，热浪适逢美国250周年纪念日，这是一年中最盛大的暑假。
Krishnamoorti说:“每个人都将在7月4日的周末回家，因此，我认为，你将看到电网的重大负荷。”“住宅制冷将成为需求的主要来源，从下午到晚上这段时间，这一点将非常重要。”
他说，热浪期间的夜间温度预计很少或没有缓解，阻止电网运营商让发电厂离线进行日常维护。
他说，一些公用事业公司可能不得不在局部地区实施轮流停电，以减轻电网压力。
Krishnamoorti表示，向马萨诸塞州、康涅狄格州、缅因州、新罕布什尔州、罗德岛州和佛蒙特州供电的独立系统运营商新英格兰(ISO-New England)也可能面临满足需求的挑战，因为它从加拿大进口了一些低成本电力。
“加拿大也正在经历一场严重的热浪，”Krishnamoorti说。“所以，我不确定加拿大是否有足够的供应量将它运过边境。”
在给ABC新闻的一份声明中，ISO-New England表示，它已经为热浪的挑战做好了准备。
“从高层面来看，由于气温非常高，特别是明天(周四)，我们预计本周系统将面临紧张状况。ISO-New England的发言人Matthew Kakley说:“像这样的天气事件在地理上遍布我们的邻近地区，会限制我们相互援助的能力，但我们仍与纽约和加拿大的合作伙伴保持密切联系，了解他们所在地区的情况。”。
该公司表示，预计周四的峰值需求将为25，850兆瓦，低于2006年8月2日创下的28，000兆瓦纪录。
“我们预计有我们需要的资源来满足消费者的需求和所需的储备，但我们将密切关注情况，”卡克利说。“如果需要，我们的运营商有工具可以帮助确保供需平衡。”
'Stretched to the limit': Heat wave prompts US electrical grid emergency
With 160 million people in 30 states under alert for extreme temperatures, the U.S. Department of Energy has declared an emergency as aheat wavebears down on a huge part of the nation's electrical grid.
U.S. Secretary of Energy Chris Wright issued an Energy Emergency Alert, directing officials of the biggest electrical grid, PJM Interconnections in the Mid-Atlantic region, to take action to prevent blackouts and ensure essential operations like hospitals are fully functioning during the heat wave.
"Maintaining affordable, reliable, and secure power in the PJM service territory is non-negotiable," Wright said in a statement on Tuesday.
PJM supplies power to about 65 million customers in Washington, D.C., and in all or parts of 13 states, including Delaware, Michigan, Maryland, Kentucky, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia.
Wright's emergency declaration, which went into effect at 11:59 p.m. on Tuesday and will run through 11:59 p.m. on Friday, also directs PJM to conserve energy by curtailing power to data centers that have backup generators and other non-emergency facilities that use a lot of electricity.
PJM said it is forecasting an electricity peak demand of 166,304 megawatts, or the average total electrical demand by consumers for one hour, on Thursday -- which would break a record set in 2006.
The dangerous heat wave is bringing prolonged extreme heat along the East Coast, the Midwest and the South.
Leading into the Fourth of July holiday, heat indices, or what the temperature feels like with high humidity, are forecast to soar to 100degrees in Chicago and Detroit, 110 in New York City, 112 in Philadelphia, 113 in Washington, D.C., and 111 in Nashville, Tennessee.
"It's going to really strain the grid," Ramanan Krishnamoorti, vice president of energy and innovation at the University of Houston, told ABC News. "I think we’re going to see peak demand that is going to be a record across different geographical areas."
The New York Independent System Operator (NYISO), which operates the state's electrical grid, said it is also expecting electricity demand to approach record highs over the next few days.
The Midcontinent Independent System Operator (MISO), which covers 15 states in the Midwest and South, said it could also break its record for peak demand.
"Everything is sort of stretched to the limit," Krishnamoorti said. "I think you're going to see massive challenges in terms of demand."
Making matters worse is that the heat wave is coinciding with the biggest summer holiday of the year, America's 250th birthday.
"Everybody is going to be home for the July 4th weekend, and because of that, you’re going to see, I think, a significant load on the grid," Krishnamoorti said. "Residential cooling is going to be the dominant source of where the demand is going to come, and it's going to be pretty significant through the afternoon to late evening period."
He said nighttime temperatures during the heat wave are expected to provide little to no relief, preventing grid operators from taking power plants offline to conduct routine maintenance.
He said some utilities may have to implement rolling blackouts in localized areas to relieve the stress on the grid.
Krishnamoorti said Independent System Operator-New England(ISO-New England) -- which provides power to Massachusetts, Connecticut, Maine, New Hampshire, Rhode Island and Vermont -- could also face challenges meeting demand because it imports some of its low-cost electricity from Canada.
“Canada is also going through a significant heat wave," Krishnamoorti said. "So, I’m not sure there will be enough supply from Canada to bring it across the border."
In a statement to ABC News, ISO-New England said it is prepared for the challenges of the heat wave.
"At a high level, we're expecting tight conditions on the system this week due to the very high temperatures, particularly tomorrow (Thursday). Weather events like these, which spread geographically across our neighboring regions, can limit our ability to assist each other, but we remain in close contact with our partners in New York and Canada about conditions in their areas," said Matthew Kakley, a spokesperson for ISO-New England.
The company said it anticipates its peak demand will be 25,850 megawatts on Thursday, which is below its record 28,000 megawatts on Aug. 2, 2006.
"We anticipate having the resources we need to meet consumer demand and required reserves, but we will be closely monitoring conditions," Kakley said. "If needed, our operators have tools at their disposal to help ensure supply and demand are in balance."
