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Green hydrogen in the energy transition: Focused use is indispensable

Hydrogen should be the savior in the energy transition. What cannot be electrified directly or with sufficient comfort should be powered by hydrogen. Accordingly, the German federal government assigns hydrogen an important role in the decarbonization of the German economy. Our series of articles wants to take a closer look at the plans of the federal government and shed light on specific areas of application – especially in the automotive sector. Whatever is technically possible should also be checked for efficiency and scalability.

The federal government aims to make Germany greenhouse gas neutral by 2045. By 2030, the CO2-Emissions will already decrease by at least 65 percent compared to the base year 1990, by 2040 by at least 88 percent. These goals are in the recently amended Climate Protection Act and require an acceleration of the energy transition. The main building blocks for this are the accelerated expansion of renewable energies and an increase in energy efficiency. Also plays the so-called sector coupling an increasingly important role, i.e. the direct or indirect use of electricity from renewable energies for previously non-electrified areas of application in transport, heating and industry.

Against this background, the role of hydrogen in the energy transition is currently being hotly debated in politics, business and research. Hydrogen also plays a role in the parties’ election manifestos for the Bundestag election. The term is used 25 times in the current CDU / CSU program, 21 times with the Greens, 13 times with the FDP and 12 times with the SPD and the Left.

In the programs for the last federal election in 2017, hydrogen was not yet an issue. Four years ago, the term was only mentioned once by the CDU / CSU and the Greens, but not at all by the other parties.

Dr. Wolf-Peter Schill is deputy head of the Energy, Transport, Environment department at DIW Berlin and heads the research area “Transformation of the Energy Industry”. His main research interests are open source electricity sector modeling and the integration of renewable energies through energy storage and sector coupling. He publishes regularly in relevant international journals. He is a member of the National Platform Future of Mobility, the ESYS working group Hydrogen Economy 2030 and the Leibniz Research Association Energy Transition.

Martin Kittel is a research associate in the Energy, Transport, Environment department at DIW Berlin and a doctoral candidate at the DIW Berlin Graduate Center. His research focuses on the model-based analysis of the decarbonization of the European electricity markets and flexibility options for integrating fluctuating renewable energies.

The focus is particularly on so-called green hydrogen, which is generated by electrolysis. Water is broken down into its components hydrogen and oxygen using electricity from renewable energies. Electrolysis does not produce any emissions that are harmful to the climate. In principle, green hydrogen could be used for a wide variety of applications in practically all sectors and replace the use of fossil fuels there.

About a year ago the federal government has presented its national hydrogen strategy. It contains overarching goals for the market ramp-up of hydrogen in Germany, describes various development areas and fields of action and names some – more or less specific – measures. A hydrogen demand of 90 to 110 TWh is projected for the year 2030, of which up to 14 TWh are to be produced in Germany. By 2050 this demand will rise to up to 380 TWh. It is assumed that most of the hydrogen demand will have to be imported not only in the short term, but also in the long term. In principle, the National Hydrogen Strategy is strongly influenced by technological and industrial policy considerations. The question of the optimal role of hydrogen in the future energy system is less of a focus.

At the federal level there are also various measures to promote research and development as well as demonstration and market ramp-up of hydrogen technologies. Various funding programs are included from the federally owned NOW GmbH coordinated, in particular the National Innovation Program for Hydrogen and Fuel Cell Technology (NIP).

The National Hydrogen Council has also been advising the Federal Government since mid-2020. This body consists of experts, especially from research, business and civil society, and draws up studies, statements and position papers, most recently including an action plan to kick-start the market ramp-up of the hydrogen economy in Germany within the next legislative period.

Although hydrogen is a colorless gas, it has many colors in the current debate. The focus of the National Hydrogen Strategy, as well as most research and development projects in Germany, is on green hydrogen from water electrolysis. Other potentially greenhouse gas-neutral manufacturing processes based on fossil fuels, e.g. so-called blue hydrogen (based on natural gas, with CO2-Deposition and permanent underground storage) or turquoise hydrogen (methane pyrolysis, with solid carbon as a by-product) are left out.

Whether and to what extent they should also be used at least temporarily as part of a market ramp-up, is controversial. In particular, it is controversial whether part of the carbon emissions produced will be released into the atmosphere in the short or long term, and whether the construction of corresponding production facilities would lead to undesirable path dependencies or whether they would become stranded assets.

Hydrogen is currently used in various industrial processes, in Germany to the extent of approx. 55 TWh annually. This is usually conventional, so-called gray hydrogen. It is made on the basis of natural gas by steam reforming without CO2-Separation is established and has no future due to the high emissions. There are also a few other “shades of color” for other production processes for hydrogen, based in part on different starting materials and with various by-products.

Hydrogen production options: raw materials, processes, by-products and associated colors. Green hydrogen from water electrolysis with renewable electricity is most relevant in the context of the energy transition.

(Image: Advisory Council for Environmental Issues, Opinion “Hydrogen in climate protection: class instead of mass”, 23.06.2021.)

To be distinguished from hydrogen are synthesis products that can be generated on the basis of green hydrogen in so-called Power-to-X processes (PtX). These substances include synthetic natural gas and various liquid fuels, the production of which is also known as power-to-liquid (PtL). Such hydrocarbons are catalytically synthesized from green hydrogen and a climate-neutral carbon source. As so-called e-fuels, they can replace natural gas and petroleum-based fuels.

In the energy policy debate, there is often no clear distinction between pure hydrogen applications and those for e-fuels. In the energy system analysis, too, both energy sources are often considered together. It should be noted that there are significant differences in both energy efficiency and infrastructure requirements for hydrogen and e-fuel applications. Greenhouse gas emissions can also be very different, depending on the electricity mix and carbon source.

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