As we've mentioned before, Google is quite interested in plug-in hybrids. For those not familiar with the technology, a plug-in hybrid is just like a regular hybrid - it can be powered by either a gasoline engine or electrical motor, or both at the same time - except that you can also plug it in the grid to recharge the batteries, allowing a longer all-electric range. As they've said in Davos, Google's founders thinks that plug-in hybrids are an important stepping stone towards all electric transportation. That's why they built a small demonstration fleet.
Right now, Google has 2 regular Toyota Prius hybrids and 4 modified Priuses that have extra batteries and can be plugged-in. The cars have been rigged so that real-world performance data can automatically be downloaded. Lets have a look at how they're doing.
Here's the breakdown:
-Garamba: 43.9 MPG
-Kilimanjaro: 45.4 MPG
-Comoe: 69.9 MPG & 123.8 Wh/mile
-Galapagos: 65.1 MPG & 98.9 Wh/mile
-Great Barrier Reef: 68.3 MPG & 136.2 Wh/mile
-Machu Picchu: 54.4 MPG & 117.6 Wh/mile (really bringing down the average)
Considering that according to the 2005 Highway Statistics from the U.S. Department of Transportation (Federal Highway Division), the average combined MPG for all US cars and light trucks on the road today is 19.8 MPG, Google's fleet has been doing pretty well.
Just the regular hybrids have been emitting 56% less greenhouse gases than that baseline. The plug-ins have been doing 65% better, or 20% better than the regular hybrids, and Google has been recharging their batteries with their solar installations.
We don't know exactly what kind of driving these cars have been doing (what ratio of city/highway, how fast, etc), but if we keep in mind that the Toyota Prius was not designed as a plug-in and that a third-party hack was required to turn it into one, that's a decent improvement.
It's good to see Google getting some real-world experience with plug-ins and sharing their data. One thing this highlights, though, is that we need much better plug-in hybrid fuel economy than what modified Priuses can offer. We suspect that the heavy extra battery pack used here is part of the problem. Series plug-in hybrids like the GM Volt might perform better by saving weight on the gas engine and transmission, allowing more efficient all-electric operation and higher mileage overall. Maybe hypercapacitors are part of the solution. We'll have to wait and see. ::RechargeIT
See also: ::Google Sets Ambitious Goals For Renewable Energy, ::Google to Tackle Global Warming, ::Google Ends Search For Corporate Alternative Energy Source, ::Google's Solar Trees Due To Bloom This Spring, ::An Ethanol-Powered Plug-In Hybrid? Leave it to Google