SoylentNews is people
SoylentNews
New research from North Carolina State University and the University of Colorado Boulder finds that steep declines in the use of coal for power generation over the past decade were caused largely by less expensive natural gas and the availability of wind energy -- not by environmental regulations.
"From 2008 to 2013, coal dropped from about 50 percent of U.S. power generation to around 30 percent," says Harrison Fell, an associate professor of resource economics at NC State and co-lead author of a paper on the work.
"Coal boosters blamed stiffer regulations, calling it a 'war on coal.' But that same time period saw a steep drop in the cost of natural gas and an increase in wind generation. We wanted to know how big a role each of these factors played in driving down the demand for coal."
(Score: 0) by Anonymous Coward on Saturday May 05 2018, @07:04PM (5 children)
According to this pdf here http://web.mnstate.edu/marasing/CHEM102/Chapter%20Notes/Ch_04%20ho.pdf [mnstate.edu] on pg.6.
Burning methane releases 50.1 kJ/g
Burning carbon (coal) releases 32.8 kJ/g
So burning natural gas releases considerably more energy.
Of course, the final net energy output does depend upon the efficiency of the machine doing the burning. But at the outset, a coal plant has to be more efficient than a nat-gas plant just to break even. Or a nat-gas plant can be less efficient, to an extent, than a coal plant and yet still be ahead in the end.
(Score: 0) by Anonymous Coward on Saturday May 05 2018, @07:42PM (2 children)
Methane doesn't have the same density as coal. It's full of hydrogen, the lightest element.
Methane also gets used up just sitting in place. You have to refrigerate it. No amount of pressure will liquefy it at typical temperatures, and the pressure needed to reach liquid-equivalent density is completely unreasonable.
(Score: 0) by Anonymous Coward on Saturday May 05 2018, @10:23PM (1 child)
Did you not notice the /g (meaning per gram) in the numbers from the linked pdf?
That compensates for the differing densities. The energy output is for "one gram" of each.
(Score: 0) by Anonymous Coward on Sunday May 06 2018, @05:54PM
I'd rather measure by volume. Unless you want to launch a rocket, the weight doesn't really matter.
kJ/L is OK.
That still ignores the fact that methane is time-limited. You lose it in storage because you have to expend energy to keep it refrigerated. We could go by kg/L after a year in storage at a moderately-sized facility.
(Score: 2) by frojack on Saturday May 05 2018, @07:57PM (1 child)
Not really. It depends more on the Net Calorific Value of the fuel.
Rank Type of Coal Calorific Value (MJ/kg)
#1 Anthracite___________30 millijoule per kilogram
#2 Bituminous__________18.8–29.3 millijoule per kilogram
#3 Sub-bituminous______8.3–25 millijoule per kilogram
#4 Lignite (brown coal)__5.5–14.3 millijoule per kilogram
#5 Natural gas___________45.86 millijoule per kilogram
Still gas is a good deal, and also about half the carbon released compared to coal.
http://www.claverton-energy.com/wordpress/wp-content/uploads/2012/08/the_energy_and_fuel_data_sheet1.pdf [claverton-energy.com]
No, you are mistaken. I've always had this sig.
(Score: 0) by Anonymous Coward on Sunday May 06 2018, @05:00PM
Those are Mega-Joules, not milli. Your sneezes release more than a milli-Joule.