These days, if it's not a merger, it's a joint venture. The latest in- stance concerns BMW AG, not as a target for takeover as was rumored earlier this year, but as a party forging ties with mega-supplier Delphi Automotive Systems. The companies are pushing to develop an entirely new type of fuel cell that they claim can run on pump gasoline.

The companies call it a Solid Oxide Fuel Cell, or SOFC, and it differs from the more familiar proton exchange membrane (PEM) fuel cells - like those made by Vancouver, BC-based Ballard Power Systems Inc. - in a couple of significant ways. The SOFC uses a circonium oxide ceramic transformer to convert hydrogen into electricity at roughly 1,470 degrees F (800 degrees C), and because of its hot temperature, any impurities that may be in the gasoline simply are burned off. Unlike PEM fuel cells, which are much more sensitive to the fuel's quality, the SOFC can operate on regular gasoline.

Burning off impurities sounds like a strategy that defeats the purpose of pursuing zero-emissions power generation via fuel cells. "Emissions are no different than a PEM fuel cell with a standard reformer," contends Wieland Bruch, product information specialist for BMW of North America Inc. "The hot fuel cell burns off the impurities from the gasoline, allowing for the elimination of some of the cleaning devices normally found between the reformer and the fuel cell."

The SOFC holds another advantage over PEM fuel cells in that it doesn't depend on expensive platinum-group metal electrodes. Instead, conversion begins by evaporating the gasoline and splitting off the hydrogen in a hot reformer. Then, as is the case with any fuel cell, the hydrogen reacts with oxygen in the air, to generate both electricity and one waste product: water.

And yet as BMW pushes now for the development of gasoline-fed fuel cells, it is still directing most of its alternative fuel efforts - as it has for nigh on two decades - toward the hydrogen-driven internal combustion engine.

That's right: gasoline for the auxiliary fuel cell, but hydrogen for the engine.

Not surprisingly, BMW's announcement follows shortly on the heels of similar ones from DaimlerChrysler AG and Ford Motor Co. Last month, the two automakers held a joint press conference to publicize the progress of their respective fuel cell efforts, DaimlerChrysler's NECAR 4 and Ford's P2000 programs, and to promise production fuel cell-powered vehicles by 2004. The difference, however, between theirs and BMW's endeavor is that DaimlerChrysler, originally as Daimler-Benz AG, and Ford have been working closely with fuel cell maker Ballard on their respective programs for more than a year now and have fully operational prototypes - prototypes whose fuel cells do the actual driving.

"It's not BMW's target to power the wheels with a fuel cell, at least not in the foreseeable future," says Mr. Bruch. "We doubt that it will be possible (for any automaker) to offer a competitive fuel cell-powered car by 2004. The fuel cell-powered vehicle is less efficient than the conventional internal combustion engine-powered vehicle. This will not change for the foreseeable future."

BMW maintains that it is still more efficient to use the internal combustion engine than a fuel cell to power a vehicle's wheels. BMW's SOFC would instead replace the battery and alternator and function as kind of an auxiliary power unit. And because it can operate on gasoline, use of the SOFC does not have to wait until a widespread hydrogen supply infrastructure is in place.

"The need for a fuel cell as an auxiliary power unit in our cars is more immediate than going to hydrogen (to fuel the SOFC). Of course, (using gasoline) is only an intermediate step. Ultimately, the future of hydrogen is based on the fact that we cannot proceed as we have so far, meaning relying on oil and (producing) global warming," says Mr. Bruch.

"It's also that you can produce electricity (in quantities) that you simply cannot get with an alternator and lead-acid battery. And electricity needs on-board are increasing rapidly."

BMW reluctantly acknowledges, however, that the fuel cell has viable application potential beyond the role of auxiliary power unit and that it is keeping all bases covered. "In the very long run there might be a competitive fuel cell-powered car, in perhaps 15 to 20 years," says Mr. Bruch.

"We are of course doing fuel cell research as well. We don't completely rely on the internal combustion engine. We just feel that the internal combustion engine is by far not at the end of its development life."

BMW says development of the SOFC for gasoline-powered vehicles will take at least another five years. But by 2000, just in time for the EXPO 2000 World Exposition and Clean Energy Project in Hanover, Germany, BMW will build a small fleet of 7-series sedans equipped with hydrogen-powered engines and - get this - hydrogen-fed PEM fuel cells.