What is Power-to-X (PtX)?

Power-to-X (PtX) is a 'next generation' renewable energy and storage technology based on combining existing, well-known technologies.


The PtX process transforms electricity generated by renewable energy sources into other forms of energy (e.g. hydrogen, ammonia or hydrocarbons).


Unlike electricity, these energy forms allow for storage and utilization on a more flexible basis. PtX thereby represents a significant new chapter in large-scale decarbonization of infrastructure such as heavy transport and shipping.

Which PtX process will HØST PtX Esbjerg employ to make green ammonia?

HØST PtX Esbjerg will transform electricity generated from renewables into hydrogen and ultimately into the end-product green ammonia (the ‘X’).


HØST PtX Esbjerg relies on 1 GW electrolysis technology for the production of hydrogen. In electrolysis, water is split into oxygen and hydrogen. It is a well-proven technology ready for industrial up-scaling. 


The Haber-Bosch process is a mature technology, which has been used for the production of ammonia since 1913. In the Haber-Bosch synthesis, nitrogen extracted from air reacts with hydrogen, which yields ammonia.


Globally app. 180 million tonnes of ammonia are produced every year, placing ammonia in the top-5 of most commonly produced chemicals worldwide.

What is “green hydrogen” and what determines the color?

Green hydrogen is produced using electricity from renewable energy sources. The term “green” refers to its environmentally friendly production and corresponding low carbon footprint.

The color designation is based on the method used for the hydrogen production – green for renewables, grey for hydrogen derived from fossil fuels (the most traditional production form), blue for hydrogen derived from fossil fuels with carbon capture, and yellow from hydrogen based on nuclear energy.


Why was Esbjerg chosen as the location?

Esbjerg makes an ideal fit for the production of green ammonia. The city offers proximity to an abundance of renewable power from the offshore wind farms in the North Sea, where excellent wind resources are available.


The Port of Esbjerg provides access to major European ports, e.g., Rotterdam, which ensures a favourable distribution route for the ammonia throughout Europe. Potentially the Port of Esbjerg can become a key ammonia bunkering hub in the North Sea.


Also very importantly, Esbjerg has a well-established energy industry that offers qualified staff and a solid supplier base to service a PtX plant.


Local utility company, DIN Forsyning has committed to offtake part of the excess heat from the PtX plant to use for emission-free district heating. The heat offtake enables the project to monetize a waste source, while DIN Forsyning can heat 15,000 homes and reduce CO2 emissions from district heating with 40,000 t/year.

When will construction start/end?

Construction start date has not been finally decided, but construction will last approx. 3 years from 2025-2028. The plant is anticipated to be ready for operation in 2028/29.

Where is the hydrogen and ammonia plant going to be located and how big will it be?

HØST PtX Esbjerg will be located in Måde industrial area close to the port of Esbjerg. The plant will have a footprint of app. 30 ha, equivalent to 42 football lanes. HØST PtX Esbjerg will be among the first gigawatt-scale PtX facilities in Europe, representing a capital investment of 1 billion Euro.

Will the access to the recreational area 'Måde Bakker' be restricted?

The access will neither be restricted nor impaired. The public will have full access to 'Måde Bakker' just as today.

Where will the plant be getting its green electricity from?

HØST PtX Esbjerg will consume app. 5000 GWh per year based on power purchase agreements made by HØST with wind farms and solar energy producers, who will provide green electricity specifically to the plant.


5000 GWh is equivalent to the annual estimated production from a wind farm roughly the size of the upcoming Thor Offshore Wind Farm in the Danish North Sea.


The plant will not consume electricity intended for public use.

Where will the plant be getting its water volumes from?

HØST PtX Esbjerg will use app. 1.2 million m3 of water per year for electrolysis. We will either be using water from reservoirs no longer suitable for drinking water, or we will be using waste water from DIN Forsyning's waste water treatment plant.


The final decision on which type of water to use depends on more thorough investigations into water quality and contaminants.


In both cases we will have to clean the water before putting it through the electrolysis process.

What does the name HØST mean?

HØST is Danish for ‘harvest,’ and provides references to the project's relevance to the agricultural sector.


Metaphorically speaking, the term also alludes to the plant's ability to 'harvest' and store renewable energy.

Socio-economic sustainability

What are the economic benefits?

The economic benefits are significant. The project represents an investment of app. 1 billion EUR, which will generate jobs in Esbjerg both during construction and operation for staff and suppliers in the local industry.

Will HØST PtX Esbjerg generate local jobs?

When in operation, we estimate that HØST PtX Esbjerg will generate 100-150 permanent jobs.


In a long-term perspective, HØST PtX Esbjerg has the potential to kick-start a new industry and ensure long-term job creation within PtX as next generation renewable technology. The local energy industry will gain its first experiences with HØST PtX Esbjerg.


This knowledge-build will also prepare the local industry for the Energy island project, which is envisaged to house several, larger PtX plants.

Which types of employees will be needed?

HØST PtX Esbjerg will mainly employ craftsmen, maintenance workers, technicians and engineers. There is a good competency-match between the job profiles needed to run the ammonia plant and the various types of facility-operating staff occupied today in the local oil/gas & energy industry.

Is HØST PtX Esbjerg related to the Energy island project in the North Sea?

Although CIP is involved in both projects, they are independent of each other. However, there is a link in as far as HØST PtX Esbjerg is relying on access to sufficient electricity from renewable sources, and as such the prospect of the 10GW build-out in the North Sea is also a key project driver for HØST PtX Esbjerg.

Green transition

How big is the expected CO2 reduction?

The plant itself is expected to contribute with a CO2 reduction of app. 1.5m t annually, equivalent to removing 750,000 cars from the roads. The emission-free district heating, coming from the plant’s excess heat, is expected to contribute with a CO2 reduction of up to 40.000 t annually, equivalent to removing 20.000 cars from the road.

How does HØST PtX Esbjerg support the Esbjerg Declaration's ambitious target of a 35 GW offshore wind build-out in the North Sea by 2050?

With a capacity of 1 GW, HØST PtX Esbjerg – like other large-scale PtX plants - will function as a key balancing- and storage tool in Denmark’s future energy infrastructure


The HØST plant is able to operate flexibly, scaling up and down in tune with the availability of intermittent renewable generation from offshore wind and solar.


Thereby, HØST balances the market in two ways: Offshore wind farm owners can rely on a steady offtake of their product, and consumers can look forward to a lower and more steady price on electricity.

How much electricity from renewable sources will HØST PtX Esbjerg consume?

The plant will consume app. 5000 GWh electricity per year, equivalent to the total electricity production from the upcoming Thor Offshore Wind Farm.


Does the plant produce any toxic substances?

The plant produces hydrogen via electrolysis, which is then used for the production of ammonia. Hydrogen is not classified as toxic, but ammonia is toxic to people and to the environment.


The plant is therefore categorized as a so-called ‘kolonne-3’ facility in the Danish Risk Act ‘Risikobekendtgørelsen.’ Strict regulatory requirements prescribe that the plant can only be approved if it has been documented that the facility will not impose risk to people and to the water environment. A number of risk analyses and risk mitigating measures must therefore be carried out before the Danish authorities will approve the building of the plant.


It will be our number one priority to minimize the risk of accidents and to ensure the application of the highest design standards for safety and protection.

How toxic is ammonia?

Very high concentrations of ammonia or long-time exposure to ammonia is toxic to the environment and to people. Accident records from ammonia-producing countries show that serious injuries occur close to the scene of a spill/leakage.

Sufficient distance to the scene of the accident or staying indoor, can normally prevent humans from suffering serious harm from an ammonia spill.


Ammonia smells like household aqueous ammonia. The odor is very strong already at very low - still harmless - concentrations, and together with stinging in the eyes, nose and throat it will prompt people to remove themselves immediately from the area.



Is there a risk of leakage or spills?

Under normal circumstances there will not be any leaking of toxic substances from the ammonia plant. Ammonia is in the top-five of produced chemicals worldwide, and there is a wealth of knowledge and experience about how to handle the substance safely.  

Firstly, the ammonia produced at the plant in Esbjerg, will be stored at minus 33 degrees Celcius as a non-pressurized liquid. This is regarded as the safest way to store ammonia.  

Secondly, to reduce the risk of spills in connection with accidents, we will implement a number of safety precautions, which identify and contain a spill effectively, thereby safeguarding neighbouring communities. This includes for instance several barriers to physically contain the ammonia spill within the plant perimeter, and deluge and sprinkler systems to effectively combat ammonia vapours. 

Finally, all safety measures and contingency plans must be approved by the Danish authorities before the plant can be built.

How are spills prevented?

The structures, pipes and tanks which will be used for ammonia will be designed and fabricated according to the highest safety standards. They include e.g. double-walled structures, safety valves and detectors, which ensure that the plant shuts down upon the smallest indication of a possible leak. 

To reduce the risk of spills in connection with accidents, we will implement a number of safety precautions, which identify and contain a spill effectively, thereby safeguarding neighbouring communities. This includes for instance several barriers to physically contain the ammonia spill within the plant perimeter, and deluge and sprinkler systems to effectively combat ammonia vapours. 

Finally, all safety measures and contingency plans must be approved by the Danish authorities before the plant can be built.

Is there any danger of explosion?

Ammonia (NH3) burns poorly and is not regarded as explosive. In its natural form, ammonia is a liquid which keeps a temperature of -33o C. The ammonia produced at the plant in Esbjerg will be stored naturally at -33o C as a non-pressurized liquid. 


Ammonia is difficult to ignite, and it requires a temperature of 650o C to produce a flame. Even if it is ignited, ammonia cannot maintain a fire without external influences.

A chemical with the similar-sounding name ammonium nitrate (NH4NO3) can explode. The plant in Esbjerg will not produce ammonium nitrate in any form.

The plant also produces hydrogen. Hydrogen is a gas which under certain and special circumstances can explode.


The hydrogen will be safely stored in specially designed tanks placed at considerable distance from the other installations and sources of ignition. Design, tank volumes and safety measures must be approved by the Danish authorities before the plant can be built. 

Is there ammonia production in Denmark today?

Denmark does not produce ammonia today. Ammonia-producing countries in Europe include e.g., Germany, The Netherlands, France, Norway, Sweden and Finland.


However, there is a great deal of experience in Denmark with handling ammonia. For many years, liquid ammonia was used in agriculture as a nitrogen fertilizer. And the company DNK in Grenaa had actual ammonia production in Denmark over a number of years from the 1960s-1980s.


Today ammonia is still being used in many industrial facilities such as flue gas treatment plants and industrial refrigeration systems at refineries, power plants, abattoirs and dairies.


Will there be much noise coming from the plant?

During construction there will be noise coming from various construction equipment and machines. The noise is expected to be around 55-70dB which corresponds to the noise you would experience if standing 50m from a sprinting car. 


During operation, the plant must stay within the noise thresholds established by the Danish Environmental Protection Agency in the environmental approval. It is anticipated that the noise from the plant will be below 35dB. In connection with the Environmental Impact Assessment (EIA), it will be investigated whether noise-reducing measures are needed to reduce the noise level further.

Will there be ammonia smells coming from the plant?

No; there will not be any ammonia smell coming from the plant. 

Is the area protected against vandalism?

To prevent unauthorized persons to enter the plant, a safety fence will be established surrounding the plant. Moreover, the area will be under video surveillance and it will be manned around the clock. In addition security guards will regularly patrol the area.


Entrance to the facility will require special safety-approval and demonstration of relevant documentation.

Will the plant operate 24/7?

It is anticipated that the plant will run around the clock except for scheduled maintenance. As operation is depending on electricity from sustainable energy sources such as wind and solar, there will be weather situations where the plant is running at lower intensity. The noise coming from the plant will not at any time exceed threshold limits.

Will there be an increase in heavy traffic to Måde once the plant is in operation?

No; the ammonia is transported away from the plant via pipeline to a ship loading station at Esbjerg harbour. From here it is shipped away by tank ships. As such there will not be any significant increase in heavy traffic in connection with running the plant.