Monday, March 07, 2011

Gas prices making CNG look even better now

Well, as the sting of $100+/barrel oil prices starts hitting the pumps, my decision to go CNG is feeling pretty good. (Note to my European friends, I realize most of you can't hardly remember a gallon of gas costing $4.00, but it's a real shocker in the U.S.)  Here's a check-in for how things are going to far:
  1. The purchase and installation of the Phill home refueling unit was a bit more than I had anticipated.  By the time I purchased the unit for interior use and had the unit installed by a certified installer, it was about $6,000 for the home refueling unit.  $2,000 comes right off the top as a tax credit, so net cost was $4,000.  Since I don't have a convenient CNG fuel station near me, this was my only option.
  2. Refueling has been going fine.  The unit makes a bit of noise when it's running, but because it's in the far side of my garage, I can't hear it from inside the house.  If I run the tank on my car down to empty, it takes nearly 16 hours to refuel.  I've taken to plugging it in when the tank is between 1/4 and 1/2 and it fills up overnight.  It's pretty cool coming out to your garage in the morning and discovering a full tank of gas in the car.
  3. So, what about fuel cost?  I thought it was going to work out to about $1.00/gallon, but it turns out I was off a bit.  I applied for the poorly named Electric Vehicle Charging Rate (E-9) with PG&E.  It turns out you are eligible for this rate if you use a home refueling unit with a CNG refueling unit.  See here for more info.  I also applied for the G1-NGV natural gas rate which brings down the rate I pay for natural gas.  For the purposes of this gas calculation, I'm going to ignore the fact that these rates will actually save me money on other gas & electric I use in my house.  We'll just call that a bonus.  Under my new rate tiers, I now pay $0.91 per therm, which is the equivalent of $1.13/gge for gasoline gallon equivalent.  A gge is the same amount of energy of a gallon of gasoline, and I'm getting about 32 mpg.  So, I'm paying $1.13 for the gas, but I also have to run the compressor to compress the gas up to 3600 psi, the maximum pressure of a full tank of gas.  It takes about 16 hours to deliver 6 gge's, or about 2.5 hours per gge.  I'll spare you the math, but that's another $0.25 ~ $0.50 to compress the gas into the car, depending on what time of day I fill the tank.  Most of my filling is done overnight, so I'll be paying PG&E's lowest rate of $0.25/gge, for a grand total of $1.38/gallon!  Compared to the $4.00+ I'm seeing at the corner gas station, this is a pretty good deal.  Add to that the white carpool stickers and cleaner burning fuel that relies less on foreign production, and I'd have to say I'm happy with my decision.