Vehicles that run on diesel fuel, ethanol, natural gas, even hydrogen, are coming to market.
Don't expect gasoline vehicles to go away — gas will continue to be the dominant fuel well into the future.
But as consumers and manufacturers grapple with the economic, psychological and political impact of $4 per gallon gas and the fear that $5 per gallon gas may not be too far away, alternatives are becoming more viable.
Here's an update of what's out there and what's coming in the next 18 months.
Anyone who has traveled outside the United States can't help but notice that a lot of the rest of the world runs on diesel fuel, thanks to tax breaks and less resistance to the idea of diesel power.
Now, diesels — primarily used in trucks in the United States — are trickling into the U.S. car market. The first diesels are arriving from Volkswagen and Mercedes-Benz, but Saturn, Ford, Chrysler and Honda have diesel versions of their sedans in the pipeline.
These new diesels are much cleaner — many can even pass California's more stringent emission standards — quieter and more powerful than diesels of old.
The advantages of a diesel car are several. The fuel mileage is greater than a similarly sized gasoline engine, thanks to the diesel's low rpm range and how it fires each cylinder using extreme compression rather than a conventional spark plug. Also, a diesel engine lasts much longer without an overhaul than a gasoline engine.
The drawbacks are a higher price for a diesel-powered vehicle over the same vehicle with a gasoline engine — sometimes several thousand dollars higher — and the current price of diesel fuel, which in most parts of the country is much higher than a gallon of regular gasoline.
If states and the federal government should change the tax status of diesel fuel to perhaps mirror European policies, diesel cars could become far more popular than they were in the past.
The more rabid fans of gas-electric hybrids, such as the Toyota Prius, have long argued for modified versions that could be recharged at home or work, greatly cutting down on the use of the gasoline engine.
After resistance by Toyota and other manufacturers to home-modified hybrids — cases in which owners converted them to plug-ins — it now appears that factory plug-in hybrids are on their way to market, at least in limited numbers.
In the 1990s it seemed like all-electric vehicles were on the cusp of becoming widely available, but General Motors withdrew its limited edition two-seat EV1 all-electric coupes, saying they weren't economically viable for production. Other manufacturers shelved their electric vehicle plans, too.
Now, electric vehicles are on the verge of a comeback.
Tesla Motors, a California company, is selling a high-performance two-seat all-electric sports car that it says can go from zero to 60 mph in under four seconds and go more than 200 miles on a charge. The price is more than $100,000, however.
GM is making another stab at an electric vehicle, but with a twist.
The Chevy Volt, which is planned for sale sometime late in 2010, uses lithium-ion batteries that can be charged at home or draw a charge while running from a small onboard engine that could either be gasoline- or diesel-powered. No price has been announced, but rumors suggest the sedan could cost more than $40,000 and GM may seek some federal tax credits to help knock that price down.
Other electric vehicles are in the planning stages, with the key to production resting on the development of better batteries.
Once residing in the imagination of science fiction writers, hydrogen-powered vehicles are now available. Honda is delivering its first FCX Clarity hydrogen-powered sedans in the Los Angeles area.
About the size of a Civic sedan, the FCX Clarity uses hydrogen to power on-board fuel cells that provide electricity to power the car's electric motors.
Los Angeles is the test city because it has a handful of hydrogen pumping stations and is home to Honda's U.S. headquarters and the resulting tech staff, should something break. Honda isn't selling the FCX Clarity — hand-picked customers agree to a three-year, $600 per month lease.
Also on the road, though not ready for sale, is a hydrogen-powered BMW 7 Series sedan. Unlike Honda, BMW is developing a system in which a somewhat conventional internal combustion engine burns hydrogen. The experimental BMW can also burn gasoline when hydrogen isn't available.
Both Honda and BMW say that their on-board storage systems are safe from explosion in the event of a crash.
Tech and safety issues aside, don't expect hydrogen to become widely used unless and until an infrastructure to deliver hydrogen to neighborhood service stations arrives.
Ethanol and biodiesel
The most touted alternative fuel today is E85 ethanol, which is 15 percent gasoline mixed with agriculturally derived alcohol.
Its advantage is that the U.S. would need far less imported oil if the U.S. fleet were to run on E85. But the drawbacks are not insignificant.
Ethanol delivers fewer miles per gallon than gasoline and can cost as much or more as regular gasoline, depending on tax subsidies and regional pricing differences. Also, ethanol is not widely available and cars not built to take ethanol have to be modified.
Then there are debatable discussions about consuming crops like corn to make ethanol when there are food shortages in the world. Although ethanol supporters say eventually it will be made from garbage and switch grasses. It's also not entirely clear whether ethanol saves more oil than it takes to produce it. Biodiesel, again a blend of agriculturally based fuel with diesel fuel, shares some of the same drawbacks.
While all these alternatives are enticing in one way or another, look for manufacturers to concentrate primarily on how to make their gasoline-powered vehicles more fuel efficient.
Expect cars to get lighter and engines to get smaller and more efficient — though not necessarily less powerful.
If you're holding off buying a gasoline-powered vehicle, you may still have to wait another product cycle before alternatives are more widely available.