阅读理解
When it comes to lowering our carbon emissions (排放), it seems that nothing is simple. Electric vehicles (EVs) act as an example of potential greenwash. “They seem very attractive at first sight,” writes The Next Web in a report. “When we look more closely, it becomes clear that they have a substantial carbon footprint.”
The rare earth metals and costly minerals included as essential ingredients in EV batteries are not renewable. What’s more, their extraction (提炼) is often anything but green.
So the question is: is it worth it? Just how much emission reduction can EVs justify? Luckily, a life cycle assessment has been done to give us some answers.
“A life cycle analysis of emissions considers three phases,” writes The Next Web. “the manufacturing phase, the use phase, and the recycling phase.” In the manufacturing phase, the battery is to blame. “Emissions from manufacturing EV batteries were estimated to be 3.2 tons of carbon dioxide (CO2), 1/4 of those from an electric car, 13 tons of CO2. Those were bigger than emissions from gas cars, 10.5 tons of CO2.” If the vehicle life is assumed to be 150,000 kilometers, emissions from the manufacturing phase of an electric car are higher than gas cars.”
In the use phase, the source of electricity the consumer is using to power their car comes into play in a major way. “To understand how the emissions of electric car vary with a country’s renewable electricity share, consider Australia and New Zealand,” continues the report. “In 2018, Australia’s share of renewables in electricity was about 21%. In contrast, the number in New Zealand’s was about 84%. Electric car emissions in Australia and New Zealand are estimated at about 170g and 25g of CO2 per km respectively. As a consumer, our car is only as green as our country’s energy mix.”
Finally, in the recycling phase, we look at vehicle dismantling(拆除), vehicle recycling, battery recycling, and material recovery. “The estimated emissions in this phase, based on a stu