There’s a long history of polls showing American consumers are “willing to pay more for green.” Measured by actual sales, it’s sometimes harder to see that effect — price is a powerful motivator.

In 2009, for instance, one research report said three in four people questioned had recently bought an Energy Star appliance or locally grown food, and that “higher price would not deter them from buying a more environmentally friendly product.” Ironically, though, another company survey, done around the same time, noted a decline in the sale of organic and green products. The bottom line is that people do want to buy green, but they’ll sometimes balk when it comes to an actual purchasing decision.

So perhaps we should apply the proverbial pinch of salt to a new University of Michigan study that finds consumers saying they’re willing to pay extra to turn their cars into climate change fighters. The basic idea is this: If your car could be equipped with carbon-capture technology, at some cost to fuel economy and storage space, would you be willing to pay? It’s kind of an academic question, because it pre-supposes that automakers are actually offering mini carbon capture-and-storage technology for your car, when in reality that option is far distant. There’s interest in the idea, though, and Georgia Tech began looking into it back in 2008.

In Michigan’s online study, a majority of the 536 respondents said they’d be willing to pay $100 if their car could reduce its carbon footprint by 20 percent, and $250 if the cut was 80 percent. They’d also accept a 5 percent fuel economy drop and a 10 percent trunk sacrifice for a 20 percent CO2 drop, and a 10 percent trunk sacrifice for a 20 percent carbon improvement.

Theoretically, vehicle-based carbon capture could lead to zero pollution internal-combustion cars (forget about EVs in that scenario). That sounds great, but not everyone is willing to cough up for it. I asked a trusted source, my wife, and Mary Ann said, "Unlikely on paying more. With same storage perhaps. Or if cuter." Now there's a challenge for automakers.

According to Science Daily, “The Georgia Tech team’s goal is to create a sustainable transportation system that uses a liquid fuel and traps the carbon emission in the vehicle for later processing at a fueling station. The carbon would then be shuttled back to a processing plant where it could be transformed into liquid fuel. Currently, Georgia Tech researchers are developing a fuel-processing device to separate the carbon and store it in the vehicle in liquid form.” The Georgia Tech graphic above shows how it works.

It’s a neat idea in theory — the tailpipe would lead not to the atmosphere but to a handy CO2 tank — but it’s likely to be both hard to pull off and expensive. The University of Michigan did its own feasibility study on onboard carbon capture here. The university’s report is somewhat skeptical that people would, in fact, be willing to pay for it.

“An important component of a consumer’s motivation to adopt eco-friendly transport is perceived financial benefit,” the report said. “This suggests that incentives beyond reduced emissions may be required to motivate consumer adoption” of vehicle-based carbon capture and storage.

Related on MNN: What is carbon capture?

Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

Turning your car into a carbon fighter, for a price
Your car could capture and store carbon dioxide for later disposal, making it zero climate emission even without batteries.