Assertion: hydrogen | /r/HasProperty | useful
Facets:
value: as a way
type: MANNER
value: as an energy source/fuel
type: PURPOSE
Source sentences:
text: However, hydrogen is useful as an energy source/fuel because it has a high energy content per unit of weight, which is why it is used as a rocket fuel and in fuel cells to produce electricity on some spacecraft.
text: In addition to transport, hydrogen may also be useful as a way to store renewable energy from intermittent sources – for example, when the wind is blowing but there is not high demand for electricity.