Before that time, submarines had operated on diesel fuel and electricity.

VOA: special.2010.06.11

The Haiti mission marked the first time in the Comfort's 23 year history that it operated at full capacity.

VOA: standard.2010.03.26

We have during much of this time operated on a five day basis.

FORBES: Vacation Is Good for Business

His reliable time sources include the national radio time signal operated by NPL, which provides the time pips on the radio, and internet time servers.

BBC: Speaking Clock: Why are people still dialling for the time?

Currently the snake bots are battery powered, which limits both the distance they can travel and the length of time they can be operated.

CNN: Snake robots slither to the rescue