VOA常速英语2019--抽水蓄能发电可减少碳排放（在线收听）

California promises to use 60 percent renewable energy sources for power generation by 2030 and all zero emission sources by 2045.At Castaic Lake, north of Los Angeles, a power plant with a double reservoir may help them do that. It’s one of 40 pumped storage facilities around the United States that is used for large-scale energy storage. A smaller site helps San Diego meet its power requirements and more are planned. The idea is simple. When you have excess energy during the day, you pump the water up a hill, and it stays there. At the end of the day, you’re able to bring that generating unit online and then supply the energy back to the grid. Producing power without burning fossil fuels, most utilities scale power is stored this way, using water. A smaller amount is stored with batteries, the kind used in electric vehicles and modern devices, in our cell phones, you know, laptop computers, but they are expensive.

加州承诺在2030年之前使用60%的可再生能源来发电，在2045年之前，实现零排放。卡斯泰克湖位于洛杉矶北部，这里有一家带有双蓄水池的发电厂，这家发电厂或许可以帮助加州实现这个目标。包括这家发电厂在内，美国全境有40家有抽水蓄能功能的发电厂，它们可以用来做大规模的蓄能。小一点的蓄能厂可以帮助圣地亚哥满足电力需求，更多的蓄能厂还在筹备中。想法很简单：如果白天有多余的能量时，把水抽到山上，不放出来。那么，一天结束了的时候，就能把这部分可以发电的水放出来，并将能量供给到电网。在不燃烧化石燃料的情况下发电，大多数公用事业规模的电力都是用这种方式来蓄能的——借助于水。还有较少的一部分是用电池储存的，即储存在电动车和现代设备中，也可以储存在手机和笔记本电脑里，但这种方式成本很高。

So the challenge is to make them larger for transportation and power system application and make it cost-effective. He foresees a future when electric vehicles are tapped for power when not in use. Solutions where these vehicles energy could be delivered to the grid, we call it V2G. That’s vehicle to grid, but it’s a long way in the future. For now, water is used to store large amounts of energy, and Los Angeles power officials hope to build a major project at Lake Mead near Las Vegas where the Hoover Dam already generates hydroelectric power. If you could add some pumps and pipelines after it goes through the dam at some point downriver, pump it back upstream back into Lake Mead and just recirculate it, then you could actually increase the efficiency and optimize that asset, creating a pump storage component to the existing power plant, further reducing carbon emissions in the region.

挑战在于能否更广泛地应用于交通和电力系统中，以及能否提高性价比。他遇见到未来电动车在不使用期间可以用来蓄能。所谓将交通工具蕴含的能量传送到电网的解决方案，我们称之为V2G，即从交通工具到电网，但未来还有很长的路要走。目前，水用来储存大量能量，洛杉矶的电力工作人员希望建造一个大型项目，地点设在拉斯维加斯附近的米德湖，因为那里的胡佛水坝已经可以进行水力发电。如果能增加一些水泵和管道的话，那么即便水向下流过堤坝，也能通过水泵的作用让水回到上游，进入米德湖，然后进行再次循环。这样就能提高效率并优化资源了。这样就能给现有的发电厂创建泵存储组件，进一步减少该地区的碳排放量。