Per unit of usable energy, burning natural gas releases only 28.66% less carbon dioxide than burning petroleum.
Per unit of usable energy, burning natural gas releases only 43.75% less carbon dioxide than burning coal, which is to say that natural gas is more than half as dirty as coal.
For all the hype surrounding "natural gas" -- routinely represented as The Clean Fossil Fuel -- I am amazed to learn how much carbon dioxide it produces.
On the other hand solar energy produces no carbon dioxide.
I wonder if anyone has put a dollar amount of value on solar energy's zero carbon burden.
I understand that anything like an exact figure is impossible.
But it should be possible to ascribe a minimum value.
Remember the combustion of a gallon of gasoline produces 20 pounds of carbon dioxide. http://www.fueleconomy.gov/feg/co2.shtml
That's 20 pounds of gas!
For perspective, consider the weight of a baloon filled with carbon dioxide, then imagine how many balloons it would take for the aggregate to weigh 20 pounds!