Hydrogen stocks are shares in companies involved in hydrogen production and applications. The article categorizes hydrogen into different types based on production methods and environmental impact. Grey hydrogen, the most common type, is produced through steam methane reforming, while blue hydrogen incorporates carbon capture. Green hydrogen is carbon-free but costly. Other types include pink, brown, black, turquoise, and white hydrogen. The article discusses the role of hydrogen in various industries, especially fuel cell technology. It highlights the significant government support for hydrogen development globally and the attractiveness of hydrogen investments to ESG investors. Challenges such as cost competitiveness and infrastructure gaps are noted, with hydrogen facing competition from battery technology. The article also shares insights on investing in hydrogen stocks, including through platforms like IG Invest and ETFs like Vaneck Hydrogen Economy UCITS ETF. Key companies in the hydrogen sector like Bloom Energy and Nippon Sanso are profiled, showcasing their contributions and challenges in the industry.