Hydrogen as an Energy Carrier and the “CCUS” term

Hydrogen as an energy carrier
Hydrogen as an energy carrier

Since hydrogen is an energy carrier rather than an energy source, it could play a similar role to electricity in the future. Different energy sources and technological advancements can produce both electricity and hydrogen. Both are adaptable and have a wide range of applications. Neither the usage of hydrogen nor the generation of electricity results in the production of greenhouse gases, particulates, sulfur oxides, or ground-level ozone. Only water is released when hydrogen is utilized in a fuel cell. Production of hydrogen and power from fossil fuels like coal, or oil, might result in high CO2 intensity upstream. Only employing renewable or nuclear energy as the initial energy input or outfitting fossil fuel plants with CCUS will be able to overcome this drawback.

The distinction between hydrogen and electricity

The primary distinction between hydrogen and electricity is that the former uses molecules rather than just electrons as its energy carrier. All the justifications for why hydrogen might occasionally outperform electricity are supported by this distinction. Chemical energy is appealing because it can be safely stored and transferred.  Molecules can be kept for a long time, transported by ship across the ocean, heated to high temperatures, and employed in the infrastructure and business structures already in place that is based on fossil fuels. Because hydrogen has a molecule nature, it can be mixed with other elements like carbon and nitrogen to create fuels that are simpler to handle and can be utilized as a feedstock (Any renewable, organic resource that may either be utilized directly as fuel or transformed into another fuel or energy product is referred to as a feedstock) in industry, which reduces emissions.

A decarbonized energy system based on electricity would be significantly more flow-based without hydrogen. Flow-based energy systems can be subject to supply outages and must match demand and supply in real-time. Chemical energy can considerably increase the resilience of an energy system by introducing a stock-based component to an energy market.

Every time an energy carrier is created, transformed, or consumed, efficiency losses occur, including fossil fuels. In the case of hydrogen, these losses might add up throughout several stages of the value chain. The energy delivered can be less than 30% of what was in the initial power input after converting electricity to hydrogen, transporting it, storing it, and then converting it back to electricity in a fuel cell. Because of this, producing hydrogen is more “expensive” than producing electricity or natural gas. It also offers a case for reducing the number of energy carrier transformations along any value chain.

Hydrogen as an energy carrier
Hydrogen as an energy carrier
Energy Efficiency

That being said, efficiency can essentially be a matter of economics, to be taken into account at the level of the entire value chain. In the absence of restrictions on the supply of energy and as long as CO2 emissions are priced. This is significant because hydrogen has the potential to be produced with no greenhouse gas emissions. In addition, it can be used in some applications with much higher efficiency. For instance, a hydrogen fuel cell in a car is about 60% efficient, compared to a gasoline internal combustion engine’s efficiency of about 20%. A modern coal-fired power plant’s efficiency of about 45%, with electricity power line losses accounting for an additional 10% or more.

In order to produce hydrogen from fossil fuels with lower CO2 emissions, “blue hydrogen” is frequently used. Using a technique called steam reforming, which combines natural gas and heated water to create steam, blue hydrogen is mostly made from natural gas. Hydrogen is produced, with carbon dioxide as a byproduct. So, in order to capture and store this carbon, carbon capture and storage (CCS) is crucial.

Carbon Capture, Utilization, and Storage are referred to as CCUS. As a result, it is not the end result of a single activity. It is the culmination of various carbon life cycle stages. While CCU (Carbon Capture and Utilization) or CCS (Carbon Capture and Storage) are the actual processes, the term “CCUS” is somewhat misleading because it suggests that the carbon is first captured, used, and then stored (Carbon Capture and Storage).

Carbon Capture

The process of removing CO2 by physical or chemical means from a combination (such as combustion process flue gas or a stream of natural gas that is CO2-rich) is known as carbon capture. Typically, one of three techniques is used to separate the carbon from the fuel: Pre-combustion, Post-combustion, and Oxyfuel combustion.

Pre-combustion is the process of separating the carbon from the fuel before combustion. The SMR process illustrates this, in which methane interacts with steam to produce CO, CO2, and H2. As a result, before being used, the fuel (methane) is separated from the CO2 and just H2 is left. After the fuel has been utilized to produce energy, the carbon is separated during a process known as post-combustion. Oxyfuel combustion is similar to post-combustion. Instead of using air to burn carbon-rich fuel, oxygen is employed. This results in more complete combustion that emits less CO and has naturally greater efficiency. There are various methods for separating CO2, however, post-combustion technologies are the main focus of most carbon capture methods.

hydrogen new energy carrier
Carbon Utilization

Utilizing carbon in an industrial process means putting the CO2 to use. If there are incentives to develop an income stream extending beyond the carbon prices in the EU ETS, for example, CO2 valorization ideas (such as CO2-enhanced processes) may become more significant as carbon capture becomes more widespread in the economy. Production businesses may find it intriguing to use CO2 in their processes to generate more cash. Of course, we need a significant enough carbon tax. Although increasing CO2 consumption to 160x might sound like a radical concept, it might be possible to reduce CO2 emissions through carbon utilization with the right incentive scheme.

Carbon Storage

The procedure known as carbon storage (or sequestration), involves injecting the separated CO2 into a subterranean geological deposit. Not all geological formations are appropriate for storing CO2; more frequently, depleted oil and gas wells are employed (or at least taken into consideration), as they have historically held pressured fluids and are therefore by definition appropriate for storing CO2. The fact that CO2 is not exactly injected in the gas phase is a key aspect of CO2 storage. Instead, CO2 is kept in supercritical fluid form.

In essence, a supercritical fluid is a fluid that has properties of both a gas and a liquid since it is above its “critical” temperature and pressure (such as high density). The Sleipnir project in Norway is one of the most significant CSS projects. It comprises a group of gas extraction wells known as Sleipner A, R, T, and B. Due to the high CO2 content of the extracted gas, a plant (at Sleipner T) separates the CO2 from the natural gas and then pumps it back into one of the wells (Sleipner A). This is a CCS removal facility linked to a natural gas extraction platform rather than blue hydrogen generating facility.


CCUS offers the chance to scale up hydrogen projects around the world. It’s not something new in the scientific area, but something that much more attention must be given. It can be used significantly to produce blue hydrogen. It is essential to move away from grey hydrogen, natural gas, and coal. We should aim toward the decarbonization of the global energy mix.

Written by our Energy Enthusiast
Pavlos Hitiris

Pavlos Hitiris Author

Pavlos has a Bachelor in International and European Studies from the Panteion University of Athens. He has worked successfully at a Law Firm in Kolonaki, Athens. Currently, he is working at a Solution Provider/System Integrator Company in Athens. Postgraduate student of the MSc in Energy: Strategy, Law, and Economics at the University of Piraeus in the faculty of International and European Studies. Speaks Greek, English, and German. He is keen on Middle East culture and history.

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