RechargeIT Plug-in Hybrid Cars

CNET has checked in with the RechargeIT project, part of a Google.org initiative to study plug-in hybrid vehicles (PHEV). So far, the numbers are disappointing, but there is some explanation for it.

Background
Google has created a small demonstration fleet of plug-in hybrids and eventually plans to include over 100 plug-in hybrids in its corporate fleet as demand grows and cars become commercially available. Google.org has contracted with Hymotion to retrofit 4 Toyota Priuses and 2 Ford Escapes.

They are also demonstrating V2G capability (Vehicle to Grid), sometimes known as a smart grid. By plugging the PHEV into a special charger during the day, the vehicle can pass back some of the energy it collected during the night, during low peak usage. By pulling energy out at night when the costs go down and passing it back during the day when electricity is more expensive, the owner can make money 'selling' the electricity back.

Low MPG Numbers for PHEV Fleet
So far, the converted plug-in vehicles are only showing a 20 mpg improvement over their hybrid (non-plug-in) counterparts. The PHEV average so far is 66.2, while the hybrid electric vehicles (HEV) has an average mpg of 44.6. Keep in mind that the US fleet average is 19.8 mpg, so 66.2 mpg shouldn't be a complete disappointment.

But the PHEV is only saving 88 gallons a year in comparison to the HEV.

So, what gives?

According to Alec Proudfoot, an engineering product manager at Google working on RechargeIT, the problem is the short distances being traveled by the testers. In the first five minutes of any trip, the gas engine comes on to power some internal systems.

If the car goes 40-50 miles, the mpg goes up to 70-100 mpg, which is what I would expect to see for an average. Proudfoot notes that he regularly sees 80-85 mpg when he goes out for longer trips.

But, not that even if they could up their average mpg for the PHEV fleet to 80 mpg, they would save an additional 30 gallons a year (about 120 gallons more than the HEV). At a 100 mpg, you would save a total of 150 gallons a year in comparison to the HEV.

That's just the way it works as the mpg numbers go up.

CO2 Numbers are Exciting
According to Google, they are very excited to see the CO2 comparisons. The PHEV have an average of 4,623 pounds of carbon dioxide for 12,000 miles of driving, compared to the standard Priuses, which might emit 6,924 pounds of carbon dioxide, according to the organization.

You can check in with the rechargeIT project through their blog.