As an AI, I can’t predict future specifics, such as the biggest hydrogen companies in 2024. However, as of now, some major companies are involved in the hydrogen industry: 1. Ballard Power Systems: A Canadian company, Ballard Power Systems manufactures PEM fuel cells. 2. Plug Power: This American company provides hydrogen fuel cell systems that powers electric motors. 3. Linde PLC: Linde, a company primarily involved in industrial gases, is also making steps in the hydrogen industry. 4. Air Liquide: French company Air Liquide has been involved in hydrogen production for a while now. 5. Bloom Energy: An American company that manufactures and markets solid oxide fuel cells. 6. FuelCell Energy: This company designs, manufactures, operates and services direct fuel cell power plants that run on natural gas and biogas. 7. ITM Power: A UK-based company, ITM Power manufactures integrated hydrogen energy solutions for grid balancing, energy storage, and the production of renewable hydrogen. 8. Nel ASA: A Norwegian company, Nel ASA produces hydrogen from electrolysis. 9. Hydrogenics (acquired by Cummins): Hydrogenics is a Canadian firm, which provides hydrogen generation and fuel cell products. Please, keep an eye on the market trends and do your own due diligence before investing in stocks.

Investing in hydrogen stocks is an exciting opportunity given the increasing focus on sustainability and clean energy technologies. Here are the nine biggest hydrogen companies projected for 2024:

1. Linde PLC – One of the world’s largest suppliers of hydrogen, Linde is well-positioned to profit from increasing demand.

2. Ballard Power Systems – This Canadian company specializes in proton exchange membrane fuel cell development.

3. Plug Power – This energy company offers hydrogen fuel cell turnkey solutions.

4. Air Products & Chemicals – Known for its atmospheric gases, process & specialty gases, this company also deals in hydrogen generation.

5. Bloom Energy – Prominent for their energy servers (called Bloom Boxes), Bloom Energy also deals in hydrogen-powered fuel cells.

6. FuelCell Energy – This company offers a variety of fuel cell solutions and is one of the leaders in using hydrogen for energy.

7. Nel ASA – A Norwegian company that specializes in hydrogen production, storage, and distribution technologies.

8. ITM Power – UK-based ITM Power specializes in the manufacture of integrated hydrogen energy systems.

9. Hydrogenics Corporation – Now a subsidiary of Cummins, Hydrogenics is known for designing, manufacturing, building and installing industrial and commercial hydrogen systems.

Please note that investing in stocks always comes with risks and it’s important to do thorough research or consult with a financial advisor before making any investment decisions.