Monday, December 8, 2008

A World Without Gas Part 2

Even if a breakthrough in battery power revolutionized the EV, there's the problem of charging infrastructure. Is the national electric grid ready to accommodate a nightly spike in power as cars are plugged in to recharge? "And what about all those cars parked at night on city streets?" says Heywood. "Will they have extension cords running back into apartments? It's sort of a suburban opportunity. It's still significant, but it doesn't get us to 100 percent right away."

According to Norwegian EV maker Th!nk, its two-seat City should cost less than a Prius and will be available in 2009. It has a range of up to 110 miles on a single charge, with a top speed of about 65 mph.

The other problem with EVs is range. Even if batteries were to achieve the 400-mile range of a gas or diesel engine, would drivers be willing to sit in a recharging station for an hour or longer? One potential solution, says Jim Sweeney, a professor of management science and engineering and director of the Precourt Institute for Energy Efficiency at Stanford University, is a battery rental model, similar to the business model proposed by Israeli start-up Project Better Place.

Project Better Place’s car looks just like a regular sedan according to reports and images on the company’s website, but with an electrical socket and a screen showing the battery power, instead of a gas gauge. The cars are said to have a range of 100 km in city driving and up to 160 km on the highway before needing to be recharged or swapped.

Instead of owning a rechargeable battery pack, EV drivers could stop at a charging station, which would pull a new one off the rack and swap it out. The charging station's battery packs could be charged at night, when the strain on the grid would be lighter, and therefore electricity would be cheaper. "The challenge is that those batteries are very valuable," says Sweeney. "If you design it so you can release them easily and quick take them out, how do you make sure that thieves don't come in and steal those batteries from parked cars? A black market would develop for them."

Hydrogen Power: Costs as well as infrastructure issues

For hydrogen-powered vehicles, range isn't the problem. Hydrogen fuel cells could provide roughly the same driving distance as gas or diesel, with fewer constraints on vehicle size and weight. The larger obstacles include the need to roll out a national network of hydrogen filling stations. Another issue is the high cost and potential scarcity of platinum, which at present is the most efficient catalyst for hydrogen fuel cells. And then there's the hydrogen itself, which must be stored under high pressure onboard the vehicles.

One possible solution to hydrogen tanks is to get rid of them entirely. "In theory, you could hold a lot more hydrogen not as a gas, but bound to solids," says Sweeney. "You would absorb the hydrogen into a solid material, and then it bonds in there and gets released gradually. Essentially it would become a new type of battery." To some extent, fuel cell vehicles are in the same position as EVs, waiting on the fringes of the automotive world for a research breakthrough to push them into the mainstream. But whereas EVs have inched into the market through hybrids, plug-in hybrid aftermarket conversions and a limited number of short-range EVs, hydrogen has barely made it out of the lab.

"To get a hydrogen system up and running, it takes a revolution," says Heywood. "And what would prompt that? Could the government do that? It would have to be willing to spend a lot of money."

Fuel Cell Car

Some hydrogen proponents believe that a gradual introduction of the vehicles will be followed by an expansion of filling stations and related infrastructure, and that the fuel's potential as an all-around replacement for oil — both in cars and for general energy production — will eventually overtake the current buzz surrounding EVs. In a more cooperative vision of the future, the two technologies could share the road. Families could use smaller, all-electric vehicles for daily commuting and errands, and a longer-range fuel cell vehicle for road trips.

To that end, EV development could actually benefit hydrogen in the long term, since both types of vehicles use electric drivetrains, with the primary difference being the source of the current that drives the various motors. Th!nk's Canny isn't ruling out the ultimate alt-fuel automotive holy grail: a plug-in hybrid with an all-electric mode for daily use and fuel cells for extended range. "If we move aggressively on electric vehicles now, the technology will be in place for the batteries and the electric motors and the rest of the hardware," says Canny. "At that point you have range and zero emissions. It's the ideal technological solution."

Other Fuel Possibilities

Although the total number of EV drivers in the United States is still in the hundreds, companies like ZAP claim that their customers have already adopted this sort of dual-technology solution. If hydrogen never takes the place of gas and diesel for extended-range vehicles, there are other liquid fuels on the horizon, such as biomass-derived fuels. Instead of converting valuable corn crops into ethanol, fuel companies could use prairie grass, switchgrass or even new, bioengineered plants. Researchers are also developing methods of turning coal into liquid fuel; the resulting carbon emissions could make it hard for automakers to meet increasingly restrictive federal standards, but if the oil is gone, it might be the cheapest short-term option.

For now, despite public interest in plug-in hybrids and other kinds of EVs, and rising skepticism about the prospects of a hydrogen infrastructure, the details of a gas-free future are still sketchy. One potential casualty might be traditional American car culture — tomorrow's more fuel-efficient cars and trucks might be smaller, lighter and less often used. There could be multiple propulsion technologies sharing the same garage, or an array of bizarre designer liquid fuels that become as commonplace as regular or unleaded gas. Electric vehicles are likely to play some role, particularly if hydrogen's fortunes continue to fall. But the shape of the post-petroleum automobile will come into focus gradually, based on early-adopter feedback and lessons learned from ethanol and other national alt-fuel experiments.

"There's going to have to be a lot of trial and error," says Heywood. "We've done an initial sorting, but there are still more options out there than we'll ultimately be interested in investing in. We've got to keep addressing these questions, coming back to them again and again, in an almost continuous way."

Based out of the Boston area, Erik Sofge is frequent contributor to Popular Mechanics and He specializes in everything scientific and technical.

Read: A World Without Gas Part 1


No comments: