Comparison of Fuel Sources
June 2013
This information is of limited practical value
I provide the following information because readers have asked for it, not because I think it's particularly useful. Nothing below will help you save electricity or save money on your electric bill. And while it's important to know that electricity generation creates pollution, since that's one reason you should save electricity, it's not important to know exactly how many pounds of coal are required to create a kilowatt-hour of electric. If you're interested in pollution then this pollution calculator is much more helpful.
Kilowatt-Hours
Electrical energy is measured in kilowatt-hours,
abbreviated kWh. See the What's a
kilowatt? section for more.
According to conversion of units, 1 kWh = 3412 Btu. But
if you actually convert some fuel to electricity, some energy
will be lost due to the inefficiency of the generating
process. We refer to this inefficiency by using the heat
rate, which is the actual amount of fuel
required to produce 1 kWh. For example, if the heat rate
is 8000 Btu, then the efficiency is 3412 ÷ 8400 = 40.6%.
Here are the efficiences for different kinds of fuels (usually
for turning a steam turbine):
- Coal: 33.6%
- Petroleum: 25.5-33.3%
- Natural Gas: 29.4-44.8%
Source: Energy Information
Administration 1,
2
(PDFs)
Coal
Sources conflict on the number of pounds of coal to create a kWh of electricity:
- Arizona Public Service Company: 1.1 lbs.
- Energy
Information Administration: 1.03 lbs.
- CoalEducation.org: 0.8 lbs. (big surprise that the coal industry claims the greatest efficiency)
Transmission and distribution losses are estimated to be
7.2% (source),
so the above figures would be adjusted downward accordingly.
An average household uses around 920 kWh/mo. If they got all their electricity from burning coal, that's 793 to 1091 pounds of coal per month.
Coal-fired plants are only 34-44% efficient at converting
coal to electricity. (EIA,
and NPC)
Natural Gas & Oil
- Natural Gas: It takes 0.01003 Mcf (1,000 cubic feet) to make 1 kWh. This includes power plant inefficiency.
- Oil (residential fuel): It takes 0.0016 barrels to make 1 kWh. This includes the inefficiency of the conversion process.
From the Energy
Information
Administration.
Water
- Solar plant with dry cooling: 80 gallons per megawatt-hour
- Nuclear plants (with closed-loop cooling): 700-1100 gallons per megawatt-hour
- Nuclear plants (with open-loop cooling): 25,000-60,000 gallons per megawatt-hour
- Coal-fired plants (closed-loop): 500-600 gallons per megawatt-hour
- Coal-fired plants (open-loop): 20,000-50,000 gallons per megawatt-hour
- Biomass (crops grown for the purpose of fuel): 40,000 to 100,000 gallons per megawatt-hour
- Natural gas fracking: 2-10 million gallons per well
Nuclear
According to Austin Energy, the Southwest Project nuclear power plant generates 2500 MW (megawatts) of electricity.
Pollution calculator
This calculator will tell you how much pollution (sulphur dioxide, volatile organic compounds, etc.) is caused by your electrical use.