About LNG
So the new thing in Long Beach (that's CA, if you're wondering) is the Liquefied Natural Gas terminal the Fed is thinking of putting in around the harbor. Naturally this has all kinds of folks up in arms about (1) the jobs it will create or (2) the havoc it will create when environmental nasties occur. Just depends on what side of the fence you're living.
But what is Liquefied Natural Gas, anyway. Is it bad? Frankly, I couldn't really get my thoughts (or my arms) around how to think about a billion cubic feet of natural gas. So I did a little arithmetic.
Seems that the good folks at Dominion Gas down in Richmond, VA are putting in a new LNG tank in
their storage farm. They were kind enough to publish some numbers. Tank size is 2.8 billion cubic feet of gas. LNG is about 1000 BTU per cubic foot, so we are talking 2.8 trillion BTU in the tank.
OK fine. Just for argument's sake...how many BTU in a nuclear bomb? Well, the bomb we dropped on Hiroshima was 14 kilotons. Did a good job of wiping out the city. A kiloton is 4.2 trillion joules. What do joules have to do with BTU? Well, they measure the same thing, heat...so we can convert between them. 4.2 trillion joules is about 4.2 billion BTU. So the 14 kiloton Hiroshima bomb was 59 billion BTU.
So where does that get us? The amount of energy in the LNG tank is 50 times the energy in the bomb we dropped on Hiroshima.
And the Feds want to put that tank in my backyard.
Next...
Been a while...so the main thing to consider with the LNG thing is how fast all that energy is released. The good folks at The Science Fair Project Encyclopedia tell us that all the energy in a nuclear bomb is released in about a microsecond. That's one millionth of a second which is pretty darn quick. So back to the LNG example, it's unlikely that all the energy in the tank could be released that quickly. LNG without air is just really cold liquid. LNG has to warm up, mix with air and become a flammable mixture before unfriendly events can occur. So what is a worst case here? Suppose a large airplane landed in the tank. We might expect the airplane to displace a volume of gas equal to the volume of the airplane. So that volume of gas would pretty instantaneously leave the surroundings of the tank and be mixed with air. How big is that volume?
Does look pretty large, but how many cubic feet? Which is the measure we have for LNG. Well, the dimensions of the fuselage, thanks to the 747 specifications are 231 feet by 21 feet just for the fuselage. Works out to a volume of 320,000 cubic feet. Add 50% again for the wings and we are close to 500,000 cubic feet. If just that volume of gas were displaced by an aircraft landing in the tank the equivalent BTU''s work out to 500 million BTU or about 1% the size of our Hiroshima bomb standard. Man, as a homeowner I feel a lot better. If the bad guys land a plane the size of a 747 into the LNG tank down the road, the instantaneous blast will merely be 1% the size of the Hiroshima bomb. Of course I will still be stuck with the total burn equal to 50 bombs. Just that first split second will be reassuringly small. Whew. Oh yeah...one detail. How quickly will the gas be displaced? Suppose the plane is diving towards the tank at a moderate 500 miles per hour. Works out to 733 feet per second. Remember that the plane is 231 feet long, so it will all be over in 1/3 of a second (231/733). Whew again.