Assertion: fuel cell | /r/HasProperty | large
Facets:
value: in the past
type: TEMPORAL
Source sentences:
text: Fuel cells that are large enough to provide energy for very long space missions would require a lot of fuel or an external power source to provide energy to resplit the water back into hydrogen and oxygen.
text: In the past, fuel cells were large and extremely expensive to manufacture, just as the first calculators and computers were.
text: If the fuel cells were large enough, the facility could supplement the local power grid.