Skip to content


Why Danish hydrogen is green hydrogen

18 September 2023

Denmark has a long tradition of active energy policy, initiated as a reaction to the first oil crisis in 1973. Over the years, aggressive pursuit of energy efficiency, system integration, and renewable energy generation has moved Denmark closer to a fossil-free energy system.

The next step is decarbonisation of heating, transportation, and industry through both direct and indirect electrification, taking advantage of the high level of renewable energy in the Danish energy system. Hydrogen is the natural conclusion of this journey. It holds considerable potential for reducing CO₂ emissions in hard-to-abate sectors and offers further potential for system integration and deployment of renewable energy sources.

Basic principles of Power-to-X:

Renewable electricity is used to split water into oxygen and hydrogen. This technology is called electrolysis. The hydrogen can be used directly, or it can be further converted into other fuels, chemicals, and materials. The excess heat generated during the electrolysis process can be used in the district heating network, thus hydrogen can be integrated into the existing energy system.

Learn more about Power to X

Power-to-X and green hydrogen

Power-to-X (PtX) is a blanket term that refers to a set of technologies that convert renewable electricity into other forms of energy products. The ‘X’ represents different energy carriers or products that can be generated through this process,  including hydrogen, e-fuels, chemicals, and materials. In Denmark, the term is used to signal that the product is not necessarily hydrogen; it could also be methane, ammonia, or synthetic fuels.

Today, nearly all hydrogen production is based on fossil fuels such as coal (brown hydrogen) or natural gas (grey hydrogen). Using renewable energy instead of fossil fuels to produce fuels and chemicals can contribute to significant CO₂ emission reductions. In Denmark, the focus is on producing hydrogen and hydrogen derivatives using only renewable energy, making Danish hydrogen exclusively green hydrogen.


The best use of hydrogen

When decarbonising light transport and space heating, direct electrification through battery-powered vehicles, district heating or electric heat pumps is the most cost-effective and energy-efficient pathway. Due to their energy losses, e-fuels are more efficient for areas where direct electrification is not possible or is associated with very high costs, such as long-distance flights, freight shipping, industrial high-temperature processes, and energy-intensive vehicles in agriculture and construction.

Green hydrogen value chain

The figure illustrates the green hydrogen value chain from a Danish perspective where the energy source is derived from renewable sources like wind and solar. Hydrogen functions as an energy carrier, crucial for balancing the energy system, and is transported through pipelines and stored in underground salt caverns. Additionally, hydrogen serves as a building block for hydrogen-based products, where hydrogen can be combined with either nitrogen for e ammonia or carbon dioxide (CO₂) for e-methanol and e-kerosene.

The Danish approach sees sectoral integration as key for the success of the full deployment of green hydrogen. This includes utilising excess heat from electrolysis in the district heating system and purifying wastewater for electrolysis.

The Danish principles for using hydrogen

Firstly, hydrogen production should be based on renewable electricity and should be fully integrated into the energy system. Secondly, hydrogen and hydrogen derivatives should only be used when direct electrification is not feasible. Thirdly, the development of the sector should be based on market terms. Finally, sectoral integration is key for the success of full deployment by, for example, utilising excess heat from electrolysis in the district heating system or using sources other than drinking water for electrolysis to create a circular process that protects drinking resources.

Green hydrogen is Danish hydrogen

This article is a part of the white paper “Green hydrogen is Danish hydrogen”. Discover Denmark’s plans to produce green fuels and decarbonise global transport and energy-intensive industries.

Explore the white paper