Some Technical and Boring Stuff About Compressed Natural Gas (CNG) – Why Is CNG a Cleaner and Affordable Renewable and Non-Renewable Alternative Fuel for the Transportation Industry
How is Compressed Natural Gas Compared to Petroleum and other liquefied Fossil Fuels?
In the uncompressed state, natural gas has a BTU content 83% of regular gasoline (since natural gas is in the gaseous state and gasoline is in the liquid state, the comparison is based on Energy Content or BTUs):
• CNG: 103,000 -BTU per therm (100 standard cubic feet); Note: 1,030 BTU/scf x 100 scf/therm; BTU – The amount of heat (energy) required to raise the temperature of 1 pound of water by 1 degree Fahrenheit.
• Gasoline (regular): 124,800 BTU per GGE; Note: This is BTU energy content of gallon of gasoline (regular)
In actual practice, an American Honda Civic GX, which is American made and delivered to run on natural gas, with a 1.8 L 4-cylinder engine and an 8 GGE natural gas tank, will give 225 – 250 mile range.
When used as a fuel for vehicles, Natural Gas is compressed to 3,600 psi not 10,000 psi.
Filling time depends on the station and compressor design. While a time fill station which will fill the tank overnight can cost from $4K to $650K, a fast fill which fills as fast as a typical gasoline station can cost about $1.5 million (the price is use in my initial posting).
With today’s 5th generation technology for vehicles unfitted for natural gas, actual MPGGE (miles per gasoline gallon equivalent) is equal to or greater than gasoline powered vehicles.
Typical dedicated NGVs can reduce exhaust emissions of (data from Clean Vehicle Education Foundation):
• Carbon monoxide (CO) by 70 percent
• Non-methane organic gas (NMOG) by 87 percent
• Nitrogen oxides (NOx) by 87 percent
• Carbon dioxide (CO2) by almost 20 percent below those of gasoline vehicles.
Heavy-Duty vehicles running on Natural Gas meet the EPA’s 2010 stringent “Engine Emissions and Fuel Requirements” of:
• Particulate Matter – 0.01 g/bhp-hr
• NOx – 0.2 g/bhp-hr
As reported by Clean Vehicle Education Foundation, the cost of natural includes the following:
• Gas Commodity (one Mcf = about 8 GGE of uncompressed natural gas
o When NYMEX Mcf was $12.00, commodity component of CNG was $1.50/GGE
o When NYMEX Mcf was $8.00, commodity component of CNG was $1.00/GGE
o Currently NYMEX Mcf is $3.44, commodity component of CNG is $0.43/GGE
• Pipeline transportation to utility’s city gate
• Local gas distribution company service
• State/Local gross receipts / use taxes and/or special assessments
• Station Maintenance
• Capital / Equipment amortization.
With all of these costs included in the at the pump price for natural gas (taxable fuel use/ sales):
• $1.45 to $1..85 (at $3.44 per Mcf)
• $1.92 to $2.32 (at $7.20 per Mcf) as compared to $3.50 to $3.70 for gasoline and 3.75-4.05 for diesel
Finally, the life-cycle costs are lower (data provided by Clean Vehicle Education Foundation).
For a Passenger Van used as a Limo:
• GVWR: >8,500 lbs. and 8,500 #, 26,000 lbs
o Blue Bird All American RE or Thomas Built Saf-T-Liner (both factory-built with CWI ISL-G engine)
• MPG 6.0 – 7.0 / DGE (avg. 18,000 miles per year) DGE = diesel gallon equivalents
• Fuel Use: 2,650 DGE/yr
• CNG Premium: $43,000 (before fed tax credit)
• Fed Tax Credit: $32,000
• Remaining Premium (assuming no grant): $11,000
• Simple Payback: 2.8 yrs
• Life-cycle cost advantage: $40,500 (based on 13 yr life @ $1.50/DGE savings).
Hope this primer help a little and did not put you to sleep.