Will Plug-ins Continue to Disappoint?

With plug-in hybrids on the way, I think most people will expect too much from them. With possible claims like "never have to re-fuel again" or 100+ mpg, we may be setting the bar too high for popular adoption.

Looking at the recent study results from google.org and now SDG&E (via GCC), we're seeing a consistent pattern of 60-70 mpg results in real-world driving (Google set up a controlled test where they got 90+ mpg). Toyota has already warned of high expectations for their plug-in Prius.

Not that 60-70 mpg is a bad fuel economy.  It truly is a great improvement over most hybrids fuel economy (although the 50 mpg from the Prius and 40 mpg from the Insight make the numbers seem less remarkable). But when you look at the price tag for the extra large batteries, are the numbers good enough?

According to the SDG&E test results over the past two years, the plug-in hybrid at 68 miles per gallon (MPG), achieved a 58-percent increase in gas mileage, a 37-percent decrease in carbon dioxide (CO2) tailpipe emissions, and a 10-percent reduction in fuel costs. Two 2007-model standard hybrid vehicles were tested and then converted them into plug-in hybrids, using a lithium-ion battery conversion kit. In the most recent study, the prototype battery was replaced with a production-model battery. The same pool of drivers was used during vehicle evaluation.

When compared with a conventional gasoline-fueled vehicle that averages 22 MPG, the plug-in hybrid achieved a 68-percent reduction in tailpipe emissions and a 54-percent reduction in overall fuel costs.

SDG&E points out the California electricity capacity could recharge as many as 4 million plug-in hybrids when charged during off-peak hours. The savings for these 4 million theoretical drivers could add up to $4.2 billion a year at today’s average gasoline price of $3 per gallon when compared to 15 cents per kilowatt-hour of electricity for 14,400 miles driven annually.

So perhaps the gas savings would be enough to offset the initial cost of a plug-in hybrid. But unless expectations are tempered, the initial reaction for new buyers will be "68 mpg? Is this all I'm getting for my money?"