Hydrogen in climate protection: Class instead of mass

Prof. Dr. Claudia Kemfert
Prof. Dr. Claudia Kemfert

SRU formulates recommendations to policy-makers

For hydrogen to contribute to climate protection, it should be produced in an environmentally friendly way and used sparingly. This is what the German Advisory Council on the Environment (SRU) recommends in a new statement. Accordingly, the market ramp-up should focus on green hydrogen from the outset and be subject to strict sustainability criteria. In the Council’s view, the use of hydrogen only makes sense in certain areas.

Renmad

As the combustion of hydrogen is locally emission-free, it is currently often considered as a climate protection option. Currently, hydrogen in Germany and worldwide is primarily produced from fossil raw materials, especially natural gas. High CO2 emissions are released in the process. In addition, methane is emitted during natural gas production and transport, a greenhouse gas that is about 84 times more effective than CO2 (based on 20 years). This so-called gray hydrogen is therefore out of the question for climate protection.

Only green hydrogen can be sustainable

Some stakeholders are therefore calling for the use of natural gas-based blue hydrogen. In this process, the emitted CO2 is partially captured and stored (carbon capture and storage, CCS). In the view of the German Advisory Council on the Environment, however, this is not a recommendable technological path. The CO2 cannot be completely captured; the methane emissions in the upstream chain cannot be prevented either. Moreover, CO2 storage is associated with environmental and health risks. Blue hydrogen is not available in the short term because the corresponding infrastructure for CO2 transport and storage is lacking and would have to be newly built.

HOC2021

Substantial investments in technologies and infrastructures would be needed, which are not compatible with the future greenhouse gas-neutral economy. In the SRU’s view, investments and state funding instruments should address green hydrogen exclusively from the outset. This plays an important role in the future energy system and can be produced from water by electrolysis without greenhouse gases using renewable energies such as wind and solar energy.

Minimize the environmental impact of H2 production

The production of green hydrogen requires large amounts of renewable electricity, as it involves high conversion losses. One third of the energy used in electrolysis is lost at current efficiencies. The losses are even higher for downstream products of hydrogen such as synthetic methane, synthetic fuels, or ammonia.

Renewable energies also have negative environmental impacts: large areas of land, raw materials and high amounts of water are consumed. This is all the more serious with hydrogen production, as significantly more energy is required than for direct electricity use due to the conversion losses. Accordingly, the effects of energy production also increase significantly. In order to minimize environmental impacts and social consequences, clear requirements should apply to hydrogen production from the outset.

Green hydrogen remains scarce and valuable

If the market ramp-up for green hydrogen in Germany is to succeed, the expansion of renewable energies must be massively accelerated. In the SRU’s view, the slump in wind energy expansion is particularly problematic and requires timely solutions. If no new and additional solar and wind energy plants are built for the production of hydrogen, the development of the hydrogen economy will even lead to higher greenhouse gas emissions in the energy system. The opinion therefore shows that the criterion of additionality must be ensured.

… Read more in the latest H2-International e-Journal, May 2021

Authors:

Prof. Dr. Claudia Kemfert, Sophie Schmalz – both from the German Advisory Council on the Environment and German Institute for Economic Research (DIW Berlin)

Alexander Franke, Gregor Jaschke – both from the German Advisory Council on the Environment

Leave a Reply