natural gas will be the go-to bridge fuel going forward as we wean away from coal and bunker fuel and diesel.  More natural gas using vehicles including trucks and trains are converting away from liquid fossil fuels.   We`ll need that bridge and so will the rest of the growing technical and educated world we are in, to get us to where we as well as the growing third world could rely on renewables for 90% and 10% or less for oil and coal and diesel.  Without a bridge fuel that includes transportation of goods and people it is a dream too far.  You cannot be economic running solar powered trains and trucks.  You`ll go broke trying running them on wind too.  Transportation makes up 90% of our use of oil and gasoline and diesel.   We need a cleaner solution to give us a way to get to the future without spending all we have trying to run trains with the wind...more so when the wind isn`t blowing.