Natural gas shutting down coal plants (with energy price comparison calculator!)

Great article on how the natural gas revolution is influencing electric power in the US, and how coal plants are threatened more by gas than by the EPA..

http://www.washingtonpost.com/business/economy/the-demise-of-coal-fired-power-plants/2012/11/21/e7ca1e6e-fdda-11e1-b153-218509a954e1_story.html

Some people quoted in this article say that if gas hits $3 – $3.25 / thousand cu. ft. then it makes more sense to burn coal… others quote as high as $6 / thousand cu. ft.  The first quote is a plant in Kentucky with local coal sources..  I wonder if retrofit costs are included in these estimates?

This got me really interested in all these numbers people throw around about coal prices and natural gas prices.  I was surprised that there isn’t an online calculator that directly compares the cost per unit energy for these different sources.  Of course I’m sure these companies have their own calculators, but a national average cost comparison would be nice.  So I created one in excel, and converted to a google doc -see below!  I don’t have time or experience to convert this to a javascript calculator but that would be amazing if anyone is interested in doing that – it could even pull the prices directly from the commodity markets or the EIA.

For some numbers, natural gas is usually quoted in these units:

thousand cubic feet = Mcf

It is currently trading around $2.86/ Mcf … you can find current prices here

It is hard to compare this directly to other forms of energy, since volume is not energy.  To convert to energy (measured in BTU) multiply by 1,023.  Then we can compare to current prices of oil, and coal:

Online Energy comparison worksheet

These are rough estimates, especially for coal, since the prices vary greatly by region, and different types of coal also have different amounts of energy (btu) in them.  Also, I don’t think transport costs to deliver coal are included in these prices… but I think it gives you a rough idea of prices and price parity between the different sources.

Another big caveat that would favor natural gas even more is that the powerplant efficiency for natural gas is generally higher than coal.  Another way to say this is that when you burn natural gas, more of that energy is converted to electricity because of the way the plants are designed, but I think this varies quite a bit from plant to plant..

From wikipedia: ” a large coal-fueled electrical generating plant peaks at about 46%. The largest diesel engine in the world peaks at 51.7%. In a combined cycle plant, thermal efficiencies are approaching 60%.”

If you want the version that you can change the prices, check it here (obviously anyone can change the prices… so the numbers in this version might be weird – see the version that can’t be changed above)

https://docs.google.com/spreadsheet/ccc?key=0AnRWJMdvf2XRdEJ2TUoySXRXODFoUzhTYTdxVm1CLUE

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