At the end of this article, Prof. Andy Frank makes the observation that parallel hybrids (Toyota Prius) are cheaper than series hybrids (Chevy Volt). This runs counter to what I've been led to believe, so since Mr. Frank is on this list, I'm asking him if he'll explain why this is. I'm still not convinced. Paul By Michael Kanellos, for Greentech Media

"The slimming of the battery essentially comes because of a focus on weight, aerodynamics, rolling resistance, new construction materials and other design factors, he said in an interview. By reducing wind resistance and weight, the company's engineers effectively are reducing the amount of work an electric engine will have to perform to get the car up to driving speeds, which in turn conserves battery power."

Here is the full text of the entire article in case the link goes bad: http://www.greentechmedia.com/articles/think-tanks-plug-in-car-aerodynamics-are-key-5561.html 

How can you quickly improve the performance of the battery in an electric car? Lose weight.

Bright Automotive, which spun out of the Rocky Mountain Institute in January, is building a plug-in hybrid vehicle that will get 100 miles a gallon (see Green Light post). Just as important, Bright is going to try to keep the car economically priced, in part by reducing the size of the battery.

The battery pack in Bright's car, conceivably, could be made 40 percent smaller than the batteries in similar plug-ins, according to CEO John Waters. To date, the relatively high cost of batteries has kept electric and plug-in vehicles at the fringes of the auto industry.

The slimming of the battery essentially comes because of a focus on weight, aerodynamics, rolling resistance, new construction materials and other design factors, he said in an interview. By reducing wind resistance and weight, the company's engineers effectively are reducing the amount of work an electric engine will have to perform to get the car up to driving speeds, which in turn conserves battery power.

"It's a revolutionary platform," he said. "The platform that's been on the road today is 100 years old. [The traditional technique for making cars] uses a lot of steel."

Granted, nearly every other electric car company is trying to increase performance through aerodynamics and new construction materials. Bright will also face the same challenges in raising capital and moving from crafting prototypes to producing commercial vehicles. But it does have experience on its side. Waters worked on the battery for the General Motors EV1 and also worked at Ener1, which makes lithium-ion batteries. Many of the other executives have years of experience in the auto business.

Weight and poor design result in a disproportionate amount of fuel consumption in vehicles, Waters said. The U.S. Post Office operates 162,000 delivery trucks that get around 10 miles per gallon, he said, and these trucks drive around 18 miles a day. If those trucks are put into use 300 working days a year, that's 87.5 million gallons of gas consumed by those white little trucks trolling your neighborhood. Boosting mileage to 100 miles per gallon conceivably could save nearly 80 million gallons of gas.

A one cent increase in the price of fuel raises the operating budget of the federal government by $8 million, Waters said.

"That's a lot of money the federal government is putting into fuel," he said.

Waters wouldn't provide a lot of details on the vehicle. Bright has built a "mule" or concept prototype with a working drive train that it demonstrated to select guests and policy makers in December. In May, the company plans to show off a commercial prototype at the Electronic Vehicle Show in Stavanger, Norway. A commercial release, ideally, could occur three or so years from now.

The car will go 30 miles on batteries before the gas engine kicks in and be street-legal. (Some manufacturers such as Zenn Motor broke into electric cars with limited speed vehicles that top out at 25 or 35 miles per hour.) Together, the gas and electric engines will give the car a 400 mile range, or far farther than the fully electric $109,000 Tesla Roadster.

Although Bright will pursue the mass market, we mostly discussed the delivery vehicle market.

Bright's vehicle will also likely keep the series versus parallel debate alive in the hybrid world. In a series hybrid, the electric engine propels the car down the road. The onboard gas engine largely exists to recharge the batteries for the electric engine. The Chevy Volt is based around a series hybrid design and so is the Karma coming later this year from Fisker Automotive.

The series hybrid architecture, however, is complex, say critics. In a parallel hybrid, both the gas engine and electric engine are used to propel the car. The Prius is a parallel hybrid and Toyota plans to use a parallel hybrid architecture in its first plug-in hybrid. UC Davis professor Andy Frank, the so-called father of the plug-in, has formed a company, called Efficient Drivetrains Inc., that will make components for parallel hybrids (see Green Light post).

"They think [series hybrids are] cheaper but [they] is not. In order to get the same performance, you have to get a much bigger electric motor," Frank said in an interview in August.

Bright is based around a parallel hybrid.