Gas emits about half as much carbon dioxide as coal per unitof energy produced.
天然气的二氧化碳产生量是每单位煤炭释放能量时二氧化碳产生量的一半。
2
Howarth and his colleagues conclude that the greenhouse gas footprint of shale gas can be as much as 20 percent greater than, and perhaps twice as high as, coal per unitof energy.
霍沃斯和他的同事综合这些因素认为页岩气的温室气体足迹比每单位能煤炭要高20%甚至高出一倍。
3
The fate of the long-planned Smith Unit No. 1 coal plant in Kentucky is one example.