One that sticks in my mind is to do with fuel economy and the greenhouse gas issue when we talk about these situations where a working vehicle is having to stand and idle so that it's running equipment—using other technologies, even fuel cells and other types of auxiliary technology—that needs to continue running while the vehicle is essentially parked, but needs that engine running to do the job. It's still producing CO2. It's still burning fuel. It's doing a job, and it's doing a job it needs to do, but there are other technologies coming down the pipe that may provide an opportunity to reduce the amount of greenhouse gas and improve fuel economy in that idling situation.
On March 15th, 2012. See this statement in context.