Assertion: natural gas | /r/RelatedTo | coal
Facets:
value: especially
type: OTHER
Source sentences:
text: Natural gas is sometimes informally referred to simply as "gas", especially when it is being compared to other energy sources, such as oil or coal.
text: Natural gas emits the fewest harmful gases when burnt when compared with the other fossil fuels, oil and coal.
text: Natural gas is a fairly clean fossil fuel when compared to coal.