Expertise for the Hydrogen Age

Balancing the energy system

Hydrogen helps to balance out fluctuations in the generation of renewable power.
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Hydrogen helps to balance out fluctuations in the generation of renewable power.

In the course of the transition to a sustainable energy economy, Germany’s coal-fired and nuclear power plants will be removed from the grid. Instead, renewable sources of energy such as wind and solar will be expected to take up the slack. The problem is that the power generated from wind and solar energy fluctuates significantly. At present, base-load power facilities such as coal-fired plants are operated in order to cover peaks in demand. Furthermore, wind parks are often located far away from consumers. Therefore, it is necessary either to transmit this power to centers of consumption via cable or to store it and then feed it into the energy system as required. Hydrogen technology is one way of doing this. Here, electricity generated from renewable sources is used to power a process of electrolysis, which splits water electrochemically into hydrogen and oxygen – a form in which this energy becomes storeable and transportable. The hydrogen produced in this way can then be converted back into electricity. This green hydrogen serves to increase the security of supply and grid resilience.

Ways of storing and using hydrogen

The hydrogen produced in this way can be used directly. For example, it can be converted into electricity by means of a fuel cell, or it can be used as a raw material in the chemical industry. The first question here is how this hydrogen is to be made available for such uses. Conventionally, hydrogen is stored at a low temperature (-253°C) or a high pressure of several hundred bars. In HYPOS (Hydrogen Power and Solutions East Germany), a BMBF initiative, a consortium of 110 members from industry and science are investigating issues related to the storage and transport of hydrogen. Fraunhofer IMWS is exploring the feasibility of storing hydrogen in a salt cavern. A transport pipeline made of metal and plastic has been constructed for this purpose.

So-called power-to-x (P2X) processes offer an alternative to a direct use of hydrogen. In this instance, hydrogen is converted into various raw materials. In a power-to-liquid process, for example, hydrogen produced with renewable energy is combined with CO2 from nonfossil-based sources to form an energy carrier such as methanol. In the BMBF-funded consortium Carbon2Chem®, which is coordinated by Fraunhofer UMSICHT, a team of researchers from Fraunhofer UMSICHT and Fraunhofer ISE are working on processes to synthesize methanol from waste gases produced in the steel industry. Might it be possible to couple the power sector with sectors of industry by means of liquid energy carriers? And what will be the impact on the German energy system when fossil-based energy carriers are replaced by renewable fuels and chemicals – and when, as a result, the energy sector becomes increasingly defossilized?

Signposts toward a hydrogen economy

What would the transformation to a largely greenhouse gas-neutral energy system in Germany mean in concrete terms? In a project commissioned by the Federal Ministry for Economic Affairs and Energy (BMWi), experts from Fraunhofer ISI have been modeling scenarios for a cost-effective and secure energy system. This will yield important guidance for discussions on the future direction of the transition to a sustainable energy economy. On behalf of grid operators, they also used the FORECAST model to investigate demand in the European energy system.

It is also the case that companies, developers and investors require precise information before they invest in hydrogen technology. Energy-system modeling conducted by Fraunhofer ISE can provide robust information here. This ranges from hydrogen-generation costs, process efficiency and hydrogen yields to feasibility studies and earnings assessments.

The success of innovative energy technology depends, among other things, on the backing it receives within government, business and society. Fraunhofer ISI is investigating the public acceptance of hydrogen technology in the EU project HYACINTH. In H2-Chancendialog, a project at the Center for Responsible Research and Innovation, Fraunhofer IAO is seeking to identify innovation based on public input, with the aim of developing new hydrogen-based solutions in collaboration with a variety of stakeholders.