Originally published in Tank Storage Magazine, Vol. 17, 2021
On 14 June 2021, the plans for kickstarting the transition from fossil fuels to renewables of all shipping in the Baltic Sea region were announced. The new fuels may be green ammonia, methanol or hydrogen made from water electrolysis and powered by wind energy. The specific project, Bornholm Bunker Hub, aims at establishing infrastructure for fuel storage and bunkering, refurbishing vessels to run on new fuels and securing fuel supply either by local production or from external sources.
This project is quite typical for a green hydrogen project, in the sense that it will require new storage facilities and solutions for hydrogen or ammonia in large scale (centralised) at the port and in smaller scale (locally as part of the appliance) in form of fuel tanks onboard the vessels.
Power-to-X and e-fuels
The effort to limit global warming calls for decarbonisation and new technologies in many sectors. Fossil fuel is being replaced by renewable energy such as wind, solar and hydro power. In domestic heating, electricity can be applied directly e.g. in heat pumps which convert electricity to heat with high efficiency. Similarly, most passenger transport may rather easily be changed from fossil-fuelled passenger cars to electric vehicles.
However, some sectors cannot easily be electrified. Where high amounts of energy are required, batteries will not be sufficient for storing and transporting energy. Heavy duty transport, shipping, and aviation all require a fuel in a liquid or gaseous form, as the weight of batteries makes it unsuitable for these applications. For these applications, green hydrogen, green ammonia, and other e-fuels will be the solution.
The new green fuels are typically made using electrolysis where electricity is used to split water into its elements, hydrogen and oxygen. If the power comes from a renewable source, we speak of green hydrogen. The hydrogen can be used directly or it may be used in a chemical synthesis producing other substances such as methane (synthetic natural gas), methanol (a liquid energy carrier that may be used as fuel or as feedstock in further industrial processes), ammonia and jet fuel. These technologies may be referred to as power-to-X, where X designates the substance produced. The fuels are often called electrofuels or just e-fuels, indicating their origin from renewable electric power and differing from fossil fuels.
Upscaling new technologies
As a global engineering consultancy company, Ramboll is assisting energy companies and infrastructure owners in demonstration projects upscaling powerto- X technologies. Electrolysers today are typically tested in megawatt scale and aiming for 100 MW or even gigawatts before 2030. To give an indication of production volumes, a 1 MW electrolysis unit will typically produce 20 kg hydrogen per hour or approximately 220 Nm3.
Underground hydrogen storage
Using hydrogen as an important energy carrier in a national energy system will require new infrastructure and large capacity hydrogen storage. A unique opportunity for low-cost, large-scale, and flexible hydrogen storage is found in natural salt caverns or aquifers. The potential for hydrogen storage in bedded salt deposits and salt domes in Europe is estimated to be significant (>100 PWh) and is broadly distributed over several EU countries. Hydrogen storage in salt caverns may also be the fastest way to realise large storage capacity for the fastgrowing European hydrogen economy.
Carbon capture and utilisation with electrolysis
On a biomass-fired power plant, preparations are ongoing for realising production of e-fuels from all renewable sources. For a carbon-containing fuel, a biogenic source of CO2 is required. Therefore, there will be carbon capture from the flue gas of the plant. In parallel, there will be an electrolyser making green hydrogen from water. And finally, CO2 and hydrogen will be synthesised into a green e-fuel that may be utilised in transportation. The activities have included engineering design, risk assessment, permission documents, and purchase documents moving the project towards the final investment decision.
Infrastructure for hydrogen and repurposing of existing pipelines
If hydrogen is to play a key role in the EU’s decarbonisation endeavour, it must be made available across the continent at the lowest possible cost. The cost of transporting hydrogen is a key challenge. Two options exist: Either hydrogen production becomes highly decentralised or significant investment in pipeline infrastructure is required.
Concept studies and strategies for gas transmission system operators have been carried out.
There is a need for connecting local hydrogen production sites to off-takers in a dedicated hydrogen network connecting Scandinavia, Germany and the Netherlands with rest of Europe. The network may be newly established dedicated hydrogen infrastructure or it may be a repurposing of existing gas pipelines. The off-takers of hydrogen will count hydrogen refuelling stations, especially for heavy duty vehicle like trucks and buses, but also industries will be end-users of green hydrogen provided by a connecting grid.
Denmark will establish the first energy islands in the world, marking the beginning of a new era for large-scale offshore wind power. Two energy islands are to be completed in 2030, and will be able to supply 5 GW of power.
The plan envisages the establishment of an artificial island in the North Sea that will serve as a hub for offshore wind farms supplying 3 GW of energy, with a long-term expansion potential of 10 GW. In the Baltic Sea, the energy island will be the island of Bornholm, where electrotechnical facilities on the island will serve as a hub for offshore wind farms off the coast, supplying 2 GW of energy. In both places the potential in production of hydrogen or ammonia is considered. Even bunkering for vessels at the artificial island in the North Sea could be considered, thereby moving both production and offtake away from the shore.
Presently, the focus is concept development and analyses in various settings. From a cost perspective being able to reduce the electric connection in form of cables to shore is highly relevant. Furthermore, the power-to-X plants may be able to balance the intermittent renewable energy. The electrolysers producing the hydrogen may operate when there is a surplus of power production and shut down when there is a need for all electricity produced for other purposes. This may improve the business case for hydrogen production as the cost of electricity is highly dominant in the production costs, and the fluctuating supply and demand of power will result in fluctuating electricity prices.
Upgrading biogas to green natural gas
Natural gas consists mainly of methane, CH4. The natural gas grids today are filled by fossil fuel. In the future, decarbonisation calls for green or so-called synthetic natural gas. There are various routes for producing green natural gas. One way is to utilise biogas and to upgrade it. Biogas contains typically 60% methane and 40% CO2. The methane part can be directly fed into the gas grid (when separated from CO2). The CO2 is an important source for biogenic carbon and can be transformed into methane by reaction with hydrogen made from water electrolysis.
The potential for upgrading biogas and changing the pipelines from black to green is being analysed.
Green ammonia for agriculture
Ammonia currently emits more than 1% of the world’s global greenhouse gas emissions. Ammonia is primarily used in fertilisers for agriculture. Today, it is produced from hydrogen from fossil natural gas in a process called steam methane reforming. The potential for decarbonising this sector is therefore huge, with replacing the grey hydrogen from fossil fuel with green hydrogen based on renewables and electrolysis.
Besides utilisation of ammonia in agriculture, it is also foreseen to be the main fuel for ocean going vessels. The production of ammonia is therefore expected to be upscaled multi-fold.
Large expansion forseen
Large increase in green fuels based on renewable energy and electrolyser technology can be foreseen. EU has an Offshore Renewable Energy Strategy aiming at expanding offshore wind power production from 12 GW today to more than 60 GW in 2030 and as much as 300 GW in 2050. Most of it will be used in the electrification of our energy systems but a fair fraction will go into to the power-to-X processes.
Furthermore, the EU has launched a Hydrogen Strategy with the goal of implementing 6 GW electrolysis in 2024 and 80 GW in 2030. Half of this is planned in EU countries, half in neighbouring countries.
However, to have the investments and implementation taking off fast and soon, there is a need for clarification of the future regulatory framework. Clarity of future tariffs on electricity or CO2 taxation on competing technologies is a must before large investment in plants in gigawatt scale will be decided.
Hydrogen is not a silver bullet solving all future challenges with global warming and realising sufficient CO2 emission reductions. Direct electrification will be a main solution for decarbonisation, but green hydrogen and e-fuels will be the main solution for the sectors hard to electrify from 2030 and onwards.