DaimlerChrysler AG and partner Mitsubishi Motors may develop fuel cell vehicles together, according to Mitsubishi officials. Joint development of fuel cell cars would be a key step towards increasing cooperation after the German-American auto company took a 34 percent stake in Mitsubishi earlier this year. "We will be beginning work on cooperative projects with DaimlerChrysler, and the development of fuel cells will be under discussion," Mitsubishi Motors said in a press release. Fuel cells, widely seen as the main alternative to the internal combustion engine for the near future, make electricity from hydrogen and emit only water and heat, a major plus with increasing environmental concerns and regulation. The companies, along with Mitsubishi Heavy Industries (Mitsubishi's second-largest shareholder) would share development costs of more than $931 million to develop small and lightweight fuel systems in four to five years, which would then be used in a mass-market vehicle, according to a report in Japan's business daily Nihon Keizai Shimbun.