MolarsIn PolyFuel's so-called eight molar methanol fuel cells, methanol, which ultimately provides the power, constitutes only 24 per cent of the fluid. The rest is water. The cells break down methanol molecules into protons, electrons and carbon dioxide. While the protons pass through a specialised membrane, the electrons can't and get shuffled into a wire that powers the device containing the cell. The by-products from the chemical reaction come together as water molecules. Rather than completely forgo batteries, notebook makers will likely come out with computers that contain both batteries and fuel cells, said Balcom. Sanyo, among other Japanese manufacturers, has committed to coming out with fuel cell notebooks two or more years from now. But other regulations could delay fuel cell notebooks from taking off. Airlines can independently ban certain products or devices from the cabin if they feel the objects could interfere with the handling of the aircraft, said a representative for the Federal Aviation Administration. The Department of Transportation could not be reached for comment. PolyFuel, based in Menlo Park, California, is a spin-off of research firm SRI Research. Investors include Intel and venture capital firm Mayfield Venture. Competitors include MTI MicroFuel Cells.