Hydrogen and CCS: a smart combination

01-02-2018

What are the benefits of hydrogen and why can the combination of hydrogen and CCS play an important role on the road to a CO2-neutral energy supply?

Both CCS1 and hydrogen are currently making the headlines. Both can play a role in the energy transition. What are the benefits of hydrogen and how can it be used to meet the demand for energy? Why can the combination of hydrogen and CCS play an important role on the road to a CO2-neutral energy supply?

The current emphasis in the energy transition is on making electricity production more sustainable by using solar and wind power and by using electricity to meet energy requirements that are currently not being met by electricity. Two examples are the introduction of the electric car and the electric heat pump. Both ensure that energy from fossil fuel – firstly petrol or diesel, secondly natural gas – can be replaced by sustainably produced electricity.

However, sustainable electricity from solar and wind power is not always the best solution to achieve a CO2-neutral energy supply. This is due to the fact that some elements of the energy supply cannot be powered by electricity or electrification is very difficult. For example, it is very difficult to generate high-temperature process heat for industry with electricity. In those cases, gas combustion is still the most obvious option. The storage of large amounts of energy is also much easier in gaseous form than in the form of electricity. The heating of buildings also requires seasonal storage, because the demand for heat is very high in winter and very low in summer.

Hydrogen as part of the solution
Hydrogen is a particularly versatile molecule. The main characteristic of the hydrogen combustion process is that it does not produce CO2 but water. For that reason, it is a perfect method to supply CO2-neutral energy, just like electricity. It can play a role in heat production, electricity production and mobility. Hydrogen as a commodity is also used in a number of chemical processes.
We also see great advantages in the storage of hydrogen compared to electricity; it can be stored in various ways, both in tanks and underground. Hydrogen can also be transported via pipelines. This transport is partly possible by using the existing gas pipeline network. Hydrogen can be converted into electricity in a fuel cell, which means that the advantages of hydrogen can also play an indirect role in the electricity system.

Different types of hydrogen 
Hydrogen can be produced in various ways, using electricity and gas. Electrolysis requires only pure water and electricity. The result is hydrogen and oxygen. This process provides CO2-neutral energy when the electricity used also comes from renewable sources, such as sun and wind. This type of hydrogen is often called “green hydrogen”.
However, in the Netherlands and the rest of the world, most hydrogen is currently being produced via steam-methane (from natural gas) reforming, which produces hydrogen and CO2. As long as we release this CO2 into the air, we call this product “grey hydrogen”. But there is a solution: CCS. If the CO2 from this process is capture and stored, the hydrogen produced is also CO2-neutral. This hydrogen is often called “blue hydrogen”. Not really green, but certainly not grey.

Blue hydrogen means smart CCS
Smart CCS is also called pre-combustion CCS, because the CO2 is captured before combustion takes place. This is in contrast to post-combustion CCS, where the CO2 has to be filtered out of the flue gases after combustion. Large-scale production of “blue hydrogen” makes it possible to reduce CO2 emissions for all hydrogen applications. Whether the hydrogen is used as a commodity or as fuel for industry, as an energy carrier for the production of electricity or for mobility.

The role of hydrogen in the energy transition
Hydrogen can therefore play an important role in the energy transition. A smart use of CCS is the large-scale deployment of pre-combustion CCS in combination with the development of a hydrogen infrastructure. This hydrogen infrastructure may enable the use of climate-neutral hydrogen in places where post-combustion CCS is not an option due to the small-scale use of energy. And as long as electricity cannot be 100% sustainably generated in the Netherlands, climate-neutral hydrogen will mainly be “blue hydrogen”. With an increasing share of solar and wind in the electricity mix, the share of “green hydrogen” will also increase. For the construction of the hydrogen infrastructure (new pipelines, conversion of existing gas pipelines, storage, filling stations), it does not matter which hydrogen is used. “Blue hydrogen” could therefore pave the way for “green hydrogen”.

 

CCS1: carbon capture and storage is the capture and underground storage of carbon dioxide gas released in the burning of (fossil) fuels.