The High Price Of High Fuel Efficiency

The National Academy of Science’s National Research Council has released a comprehensive report on fuel-saving technologies and their associated costs [full report available online here, summary in PDF format here], and it’s data-licious. Just about every currently-available (within the next five years) efficiency-improving technology was assessed, not just for efficiency gains, but for cost as well… but let’s wait on the cost part for just one moment. Above, you can see the study’s findings in regard to efficiency gain available through various near-term technologies, as applied to vehicles with 4, 6 and 8-cylinder engines. It should come as no surprise to find that conversion to Hybrids, diesels and dual-clutch or continuously-variable transmissions offer some of the greatest benefits… but what about those costs?

Well, will you look at that? All the silver bullets are expensive. Don’t you just hate it when that happens? The study’s presser summarizes:

Adopting the full combination of improved technologies in medium and large cars and pickup trucks with spark-ignition engines could reduce fuel consumption by 29 percent at an additional cost of $2,200 to the consumer. Replacing spark-ignition engines with diesel engines and components would yield fuel savings of about 37 percent at an added cost of approximately $5,900 per vehicle, and replacing spark-ignition engines with hybrid engines and components would reduce fuel consumption by 43 percent at an increase of $6,000 per vehicle.

Meanwhile, don’t even think about think about camless valves, HCCI, “advanced diesels,” plug-in hybrids, diesel hybrids, EVs or hydrogen fuel cells. The report puts all of those technologies outside of the five-year window for this report, and notes that

some of these technologies will remain perennially 10 to 15 years out beyond a moving reference.

For now, the studying continues, as the NAS builds more sophisticated models around either real or theoretical “class defining vehicles” to help them understand how integrating these technologies can cause beneficial and harmful interactions. In the meantime, the report’s strongest conclusion is that EPA and CAFE abandon MPG in favor of gallons per 100 miles and improve testing procedures because certain technologies ( probably start-stop systems, among others) do not register realistic energy savings. We can certainly agree with that much.

This report may have uncovered more questions than answers, but it’s an in-depth look at the options and trade-offs available to contemporary product planners. THe methodology, though imperfect, is well-explained. If fuel economy catches your attention, but pie-in-the-sky futuretech turns you off, this report is required reading.