Dear EarthTalk: What would be the feasibility of having hybrid cars run on E85 or biodiesel? Wouldn't this solve multiple problems?
—Bob Pendergrass, Broken Arrow, OK
Environmental advocates would love to see carmakers mass-produce a biofuel-electric hybrid. From a technology standpoint, it's a no-brainer: Major automakers already turn out vehicles that can run on E85, a blend of 85 percent ethanol, derived from corn and other crops, and 15 percent standard gasoline. Ford's light duty F-series pickups are examples of such "flex fuel" vehicles. And gasoline-electric hybrids, like Toyota's Prius, are all the rage and beginning to be ubiquitous on the roads.
Cost, however, is an issue, says Jim Kliesch of the website greenercars.org. Traditional cars and trucks powered by diesel, biodiesel or ethanol cost more to manufacture than equivalent gasoline-power vehicles. And gas-electric hybrids also cost more than conventional cars, largely because their market share is still small and economies of scale have not yet kicked in. Thus combining two costly technologies in a biofuel-electric hybrid would constitute "a double-whammy," says Kliesch, "limiting the vehicles to a very small slice of the market."
Nonetheless, Ford last year unveiled a prototype of its popular Escape Hybrid SUV that runs on E85. Like the gas-electric hybrids now on the road, the E85-electric hybrid Escape maximizes fuel economy by alternating between its internal combustion and electric engines. And it never needs to be plugged in because its high-capacity batteries store electricity generated from braking and other processes in-car.
Ford estimates that if only five percent of U.S. vehicles were powered by ethanol-electric hybrids oil imports could be reduced by 140 million barrels a year. Such vehicles would also produce about 25 percent less carbon dioxide (CO2)—a chief contributor to global warming—than traditional cars and trucks. What's holding up mass production, says Ford, is a lack of E85 fueling outlets—only 1,200 exist across the U.S.
Not to be outdone, General Motors (GM) has its own ethanol-electric hybrid in the works via its Sweden-based Saab subsidiary, which unveiled a prototype in 2006. The company claims that, whereas Toyota's gas-electric Prius emits 104 grams of CO2 per kilometer, their E85-based hybrid should emit just 15-20 grams. Industry insiders don't expect to see such a vehicle available to the public until 2010 or later.
With regard to diesel-electric hybrids, though diesel spews particulates and other nasty ground level pollutants into the environment, it contributes significantly less CO2 to the atmosphere than gasoline. And biodiesel, a form of the fuel derived from plants, is both carbon-neutral (burning it contributes no additional carbon to the atmospheric balance of the pollutant) and cleaner burning in regard to particulates. It can be used interchangeably with regular diesel in most diesel engines. Thus combining biodiesel with an electric motor in a hybrid car or truck would yield one of the cleanest burning engines on the road.
GM and Chrysler have already collaborated on developing a diesel-hybrid platform that combines dual electric motors with a diesel engine to offer unparalleled fuel efficiency. But whether such vehicles ever see the showroom floor—and whether consumers will be able to even afford them—is anybody's guess.
Dear EarthTalk: OK, once and for all, which is more environmentally friendly: paper or plastic at the grocery checkout? And didn't I just hear that San Francisco has banned plastic bags?
—Brian, Santa Clara, CA
Yes the city of San Francisco did just recently ban plastic bags. Large supermarkets and pharmacies there must eliminate plastic shopping bags by early 2008 in favor of bags made from either paper or compostable and biodegradable cornstarch. The city's Board of Supervisors cited the fact that plastic bags are a challenge to recycle and as a result occupy much-needed landfill space, while causing litter problems by easily blowing into trees and waterways, where they can kill birds and marine life.
But just because San Francisco has outlawed plastic bags doesn't mean that all indications point to paper bags being more green-friendly than plastic. A landmark 1990 study by the research firm Franklin Associates—which factored in every step of the manufacturing, distribution and disposal stages of a grocery bag's usable life—actually gave the nod to plastic bags.
Franklin's employed two critical measures in reaching their conclusion. The first was the total energy consumed by a grocery bag. This included both the energy needed to manufacture it, called process energy, and the energy embodied within the physical materials used, called feedstock energy. The second measure used was the amount of pollutants and waste produced.
The Franklin report concluded that two plastic bags consume 13 percent less total energy than one paper bag. Additionally, the report found that two plastic bags produce a quarter of the solid waste, a fifteenth as much waterborne waste and half the atmospheric waste as one paper bag.
Of course, many environmentalists still side with paper as a better choice than plastic at the checkout, mostly for the reasons cited by San Francisco's Board of Supervisors. Plastic is not biodegradable, it litters our waterways and coastal areas, and has been shown to choke the life out of unsuspecting wildlife. A recent survey by the United Nations found that plastic in the world's oceans is killing more than a million seabirds and 100,000 marine mammals and sea turtles each and every year. According to the California Coastal Commission, plastic bags are one of the 12 most commonly found items in coastal cleanups. Paper bags do not cause such after-the-fact problems, and are inherently easier to recycle.
But to the non-profit Institute for Lifecycle Environmental Assessment, "paper versus plastic?" is not the question we should be asking ourselves, since the answer is really "neither." After all, energy and waste issues aside, the manufacture of paper bags brings down some 14 million trees yearly to meet U.S. demand alone, while at the same time plastic bags use up some 12 million barrels of oil each year.
The group urges consumers to "just say no" to both options and instead bring their own re-usable canvas bags, backpacks, crates or boxes to haul away the groceries. Some supermarkets, such as the Albertson's and Wild Oats chains, even offer a small discount (around five cents) to those who do so. Another benefit of bringing your own, of course, is setting a good example so that other shoppers might do the same.