As part of its research efforts into the development of Solid Oxide Fuel Cell (SOFC) system technology, the New Energy and Industrial Technology Development Organization (NEDO) has been pursuing the development of a micro gas turbine pressurized combined cycle power generation system and 200 kW class co-generation system based on a four-year project started in 2004. A closed loop Polymer Electrolyte Fuel Cell (PEFC) system was installed onboard the "Urashima", a Japan Agency for Marine-Earth Science and Technology (JAMSTEC) autonomous underwater vehicle, which achieved the world's longest continuous cruising distance of 317 km in February 2005. In addition to these projects, efforts are being made to promote the commercialization of environmentally friendly energy systems that meet the needs of the 21st century, such as Mitsubishi Heavy Industries, Ltd. (MHI)'s own solid polymer water electrolysis (SPWE) and SOFC combined cycle power generation systems in conjunction with integrated gasification combined cycle (IGCC) systems, as well as clean combined cycle power generation systems together with the more effective use of renewable energy.