Officials from around the world have agreed to support a 1. ________ increase in hydrogen technology. Japan announced Wednesday that energy ministers or delegates from 30 countries are supporting a plan to develop hydrogen energy for 2. ________ . The 30 countries reportedly agreed to calls to increase production of hydrogen-powered mobility systems, such as fuel cell vehicles, trucks, buses, trains or ships. The goal is to make 3. ________ such systems available worldwide over the next 10 years. In addition, Japan said the officials supported a goal of setting up 10,000 hydrogen refueling stations worldwide by 2030. Such stations will be necessary to lead a successful expansion of hydrogen-powered vehicles in coming years, a statement said. To date, Asian nations are a leader in developing hydrogen technology to power 4. ________ . China, Japan and South Korea have set goals to put millions of hydrogen-powered vehicles on roads by 2030. Experts have 5. ________ the effort will cost the countries billions of dollars. Hydrogen is considered an extremely clean energy source. Water and heat are the only 6. ________ of producing it. Also, hydrogen can be made from many different sources, including methane, coal, water, or even waste. Some 7. ________ of hydrogen fuel cell technology argue that hydrogen-powered vehicles will always be a very small part of the automobile market. But supporters say that hydrogen is the 8. ________ energy source available for cars. They believe the technology will gain greater acceptance in the coming years, as more refueling equipment for hydrogen-powered vehicles is created and becomes more widely available. Many 9. ________ in China and Japan see hydrogen fuel cell vehicles as complementing electric automobiles instead of 10. ________ them. In general, hydrogen is considered a better choice for heavier vehicles that drive longer distances, like buses. So far, only a small number of automakers have made fuel cell passenger cars available to the public.