The Ford Fusion Energi. Credit: Ford

Ford unveiled its new Fusion Energi plug-in hybrid at the North American International Auto Show in Detroit this week. It didn't say much about the car, except that it will get something like 100 miles per gallon equivalent (MPGe), which is better than the Chevrolet Volt or the upcoming Toyota Prius plug-in, and that it will go on sale toward the end of this year.

Of course, 100 miles per gallon equivalent sounds impressive. Unfortunately, the MPGe figure is not very meaningful. It's useful as a way of comparing the efficiency of cars when they are operating in electric mode, but for a plug-in hybrid, which can run part time on gasoline, it doesn't tell drivers what they really want to know: how much gas the car will use and how much it will cost to operate.

According to the U.S. Environmental Protection Agency definition, MPGe is meant to describe the efficiency of the vehicle when operating using electricity alone, which in a plug-in hybrid is typically only a relatively short range—the Chevrolet Volt can go about 35 miles on the electricity stored in its battery. MPGe refers to how many miles the car can go on an amount of electricity equivalent to a gallon of gasoline.

Based on the figure of 100 MPGe, we know that the Fusion Energi will be slightly more efficient in electric mode than the Volt (93 MPGe) and the all-electric Leaf (99 MPGe).

But drivers need to know how far the car can go on electricity and under what conditions the gas engine will come on, to figure out how much gas they'd use. The Chevrolet Volt can go 35 miles on battery power before using the gas engine. The upcoming Toyota plug-in Prius will only get about a dozen miles on a charge. If your commute is 30 miles round trip, you could get away without using any gasoline with the Volt, but not with the Prius. If your commute is much longer than the Volt electric range, you may want to consider the Prius, which gets 49 miles per gallon after the electricity is gone, rather than 37 miles per gallon for the Volt.

So we don't know how far the Fusion Energi will go on battery power. We don't even know if it will be able to achieve highway speeds on electricity alone. And there's no way for drivers to know how much gas it would use, or whether it would make more or less sense to buy than its competitors.

In 15 years, a new car that gets less than 50 miles per gallon could be considered a gas-guzzler--if new fuel economy regulations President Obama plans to announce tomorrow stick. Automakers have agreed to support the new standards, which would U.S. vehicles to average 54.5 miles per gallon by 2025. Current standards require an average fuel economy of 31.4 miles per gallon by 2016.

"If upheld, the plan would lead to the biggest gains in fuel economy since government began setting mileage regulations in the 1970s and could lead to substantial changes to the cars and trucks most Americans drive," according to the Wall Street Journal.

The impact of the fuel economy standards will depend on the details of the regulations. Previous fuel economy regulations have made exceptions for light trucks and SUVs, which helped lead to a boom in sales of these vehicles, cancelling out much of the reduction in fuel consumption provided by more efficient cars.

So far, it looks like that trucks will again receive special treatment. According to the Washington Post,

The White House originally pushed for a 56.2-mpg standard, but automakers demanded a carve-out for pickup trucks, which continue to rank among their top annual sellers. That provision lowered the average fuel efficiency gains to 54.5 mpg.

"...Until the White House provides us the full details, we are not in position to assess whether this is a strong proposal or whether there are any significant flaws," said Roland Hwang, transportation program director for the Natural Resources Defense Council. "From what we've read, there are certainly aspects that are encouraging but there are potential loopholes which could be troubling. Now it appears there is an agreement, it's time for the auto industry to work in good faith to not exploit the loopholes that threaten to undermine the consumer and pollution benefits."

One European automaker executive quoted by the Wall Street Journal suggest the rules may lead to the same problems seen in the past. "It's clearly inequitable and favors manufacturers of full size trucks," the executive said. "It could have an adverse effect on real world [gasoline] consumption by driving consumers to trucks."

One provision could lead to the standards being reduced before 2025. According to the Wall Street Journal: "In a key concession to auto makers, the White House also agreed to review the rules part way through the implementation cycle to determine if they are overly harsh or lenient given fuel prices, consumer behavior and technological advancements."

Details about how fuel economy can be assessed can influence what technologies will be adopted. In some standard driving tests, benefits of certain technologies don't show up.

The Washington Post reports that changes will be made to account for potential fuel savings from solar cells and thermoelectric devices, which supply electricity for running auxiliary systems and have an indirect effect on fuel consumption.

The Post didn't provide details about why the benefits of such systems aren't seen in current tests, but here's one guess: A solar cells might run fans that keep a car cool while it's parked. That would reduce air conditioning demand, and improve fuel economy, but that savings wouldn't necessarily be measured in test drives.

Growing Algae

Solazyme, a company that makes cosmetics, and maybe biofuels, from algae has done well in its initial public offering, raising nearly $200 million. A series of IPOs from advanced biofuels companies that haven't made commercial quantities of fuel has some concerned about a bubble.

DOE Supports Molten Salt

The DOE has recently announced a number of loan guarantees for solar power plants. One of the latest is a $737 million loan guarantee that could help scale up a technology that will make it possible to use solar power after the sun sets. Concentrated sunlight heats up salts, which store enough heat to generate electricity for hours.

Better Graphene Ultracapacitors

A research team at the University of Texas has made interesting new structures from graphene—it looks like the one atom thick material has formed a network of tunnels, leading to high surface areas and potentially high energy storage.

New Stickers for Plug-ins

The EPA has released its new fuel economy label, and it has some useful features. For example, it estimates how much drivers will save in gas over five years compared to the average new vehicle (or how much more they'll spend). That seems like the single most useful bit of information a driver could have when comparing fuel consumption in vehicles, especially since mileage numbers can be misleading.

The label also attempts to fix a problem with the test versions they released last year. Those made electric vehicles look better than they are by not counting greenhouse gas emissions from generating the electricity they use. The new label at least has some fine print disclosing that emissions from coal plants aren't included. But they included something I suggested (and many others) some time ago: a link to a greenhouse gas calculator that drivers can use to estimate the emissions in their zipcode, based on the source of their electricity. In future versions, the calculator will allow you to customize your estimates based on how you drive—which can make a big difference in plug-in hybrids such as the Volt.

From the NY Times:

The new labels, which replace a five-year-old design that provided only basic information about estimated fuel economy, represent the broadest overhaul in the sticker program's 35-year history. There will be different labels for conventional vehicles, plug-in hybrids and all-electric vehicles, with cars running solely on battery power estimated to get 99 miles per gallon.