Renewable hydrogen production technologies are being developed by the U.S. Department of Energy and the National Renewable Energy Laboratory. The goal is to produce hydrogen at a cost of 2.00–3.00 kg⁻¹, competitive with gasoline for passenger vehicles. Electrolysis of water is a standard method for hydrogen production, and using wind and solar energy can make the process renewable. Biomass-to-hydrogen processes, including gasification, pyrolysis, and fermentation, are less developed but offer potential for producing hydrogen from energy crops and biomass. Solar energy can also be used to produce hydrogen from water and biomass through various conversion pathways. Concentrated solar energy can generate high temperatures for thermochemical reactions to split water. Photoelectrochemical water splitting and photobiology are long-term options for producing hydrogen from solar energy. All these technologies are in the development stage. Electrolysis of water is an electrochemical process that requires no moving parts and a direct electric current, making it one of the simplest ways to produce hydrogen. Alkaline and polymer electrolyte membrane (PEM) electrolyzers are the two main types. Alkaline electrolyzers use an aqueous solution of potassium hydroxide, while PEM electrolyzers require deionized water. PEM electrolyzers operate at higher current densities and have higher efficiency than alkaline electrolyzers. The potential for hydrogen production via electrolysis is high when using renewable energy sources like wind and solar. The U.S. has significant potential for wind and solar electricity, which can be used to produce hydrogen. The cost of hydrogen via electrolysis depends on the cost of electricity, with lower electricity costs leading to lower hydrogen costs. Biomass-to-hydrogen processes include gasification, pyrolysis, and fermentation. Gasification involves converting biomass into syngas, which can then be used to produce hydrogen. Pyrolysis involves heating biomass in the absence of oxygen to produce bio-oil, which can then be reformed to produce hydrogen. Fermentation involves using anaerobic microorganisms to produce hydrogen from sugars and other organic compounds. These processes have the potential to produce hydrogen from biomass resources, which are abundant in the U.S. However, technical barriers such as low hydrogen molar yield and high costs need to be addressed. Solar-driven thermochemical reactions involve using concentrated solar energy to split water into hydrogen and oxygen. This process requires high temperatures and is being developed by the Nuclear Hydrogen Initiative and the Solar Hydrogen Generation Research project. The goal is to develop efficient and cost-effective methods for producing hydrogen using solar energy. Photoelectrochemical water splitting and photobiology are long-term options for producing hydrogen from solar energy. These technologies are still in the development stage but have the potential to provide a sustainable and renewable source of hydrogen.Renewable hydrogen production technologies are being developed by the U.S. Department of Energy and the National Renewable Energy Laboratory. The goal is to produce hydrogen at a cost of 2.00–3.00 kg⁻¹, competitive with gasoline for passenger vehicles. Electrolysis of water is a standard method for hydrogen production, and using wind and solar energy can make the process renewable. Biomass-to-hydrogen processes, including gasification, pyrolysis, and fermentation, are less developed but offer potential for producing hydrogen from energy crops and biomass. Solar energy can also be used to produce hydrogen from water and biomass through various conversion pathways. Concentrated solar energy can generate high temperatures for thermochemical reactions to split water. Photoelectrochemical water splitting and photobiology are long-term options for producing hydrogen from solar energy. All these technologies are in the development stage. Electrolysis of water is an electrochemical process that requires no moving parts and a direct electric current, making it one of the simplest ways to produce hydrogen. Alkaline and polymer electrolyte membrane (PEM) electrolyzers are the two main types. Alkaline electrolyzers use an aqueous solution of potassium hydroxide, while PEM electrolyzers require deionized water. PEM electrolyzers operate at higher current densities and have higher efficiency than alkaline electrolyzers. The potential for hydrogen production via electrolysis is high when using renewable energy sources like wind and solar. The U.S. has significant potential for wind and solar electricity, which can be used to produce hydrogen. The cost of hydrogen via electrolysis depends on the cost of electricity, with lower electricity costs leading to lower hydrogen costs. Biomass-to-hydrogen processes include gasification, pyrolysis, and fermentation. Gasification involves converting biomass into syngas, which can then be used to produce hydrogen. Pyrolysis involves heating biomass in the absence of oxygen to produce bio-oil, which can then be reformed to produce hydrogen. Fermentation involves using anaerobic microorganisms to produce hydrogen from sugars and other organic compounds. These processes have the potential to produce hydrogen from biomass resources, which are abundant in the U.S. However, technical barriers such as low hydrogen molar yield and high costs need to be addressed. Solar-driven thermochemical reactions involve using concentrated solar energy to split water into hydrogen and oxygen. This process requires high temperatures and is being developed by the Nuclear Hydrogen Initiative and the Solar Hydrogen Generation Research project. The goal is to develop efficient and cost-effective methods for producing hydrogen using solar energy. Photoelectrochemical water splitting and photobiology are long-term options for producing hydrogen from solar energy. These technologies are still in the development stage but have the potential to provide a sustainable and renewable source of hydrogen.