pstarr wrote:I have been explaining the dangers of CNG here for a decade. For highway travel range (50 miles) the gas must be compressed to 5,000-10,000 psi. This is very dangerous, explosive in an accident and potentially deadly to the auto-truck occupants. (This is why the few CNG vehicles in use are typically in short return-routes where they low pressure tanks can be refilled all the time.)
In comparison a standard small propane tank is only filled in a range between 100 and 200 psi. A scuba tank is around 1,000 psi and is consider very dangerous.
Not to mention that a highway compressor of the type to get to 5,000 psi cost $100,000
Your explanation is nice and neat in theory, but the facts on the ground show a large number of short haul and regional haul trucks have switched or are switching their fleets over to CNG.
You are assuming facts not in evidence, none of these stories is saying the CNG is being compressed to 5,000 or 10,000 psi. If you have a link to a set of specifications where that is being done please post it.
This story is about the city of Hamilton, Ohio converting its municipal fleet and encouraging contractors like its waste removal contractor to do the same. The 35,000 gge of CNG they sold in 2015 is a real fact, not some theory made up for future projections. They expect that to increase to 50,000 gge in 2016 and continue to expand in the next five years. Compared to the USA as a whole 50,000 gge isn't much, but when you add up town after town that is pursuing this pathway the aggregate does start to add up fairly significantly.
BTW if you are talking about longer haul trucks on day routes you don't need a massive tank at extreme pressure, the figures I have seen in the literature are 100 BAR aka 1470 psi. While that is a high pressure tank it is far less than the 5,000 to 10,000 psi you are calling for. I have seen video demonstrations of carbon fiber tanks with 100 BAR being pierced. A steel or aluminum tank at that pressure effectively explodes when ruptured because the metal tears and the whole thing bursts like a balloon. With a carbon fiber tank the pressure escapes rapidly through the rupture, but because of the construction the material does not tear and the tank does not explode, it vents.