UE 08: Hydrogen Flashcards
What is missing?
Technologies of sector coupling
Power –> Heat: PtH
- E.g.: “…”
Power –> Gas: PtG
- E.g.: “…”
Gas –> Power: PtG as electricity storage
- E.g.: “…”
Gas –> Heat: PtG as heat storage
- E.g.: “…”
Gas –> Traffic: PtG as fuel storage
- E.g.: “…”
Power –> Traffic:
- E.g.: “…”
Technologies of sector coupling
Power –> Heat: PtH
- E.g.: Heat pumps, CHP-plants, electrode boiler
Power –> Gas: PtG
- E.g.: Electrolysis (H2), Methanation (H2 –> syntethic natural gas (CH4))
Gas –> Power: PtG as electricity storage
- E.g.: Reconversion to electricity via H2-/syntethic CH4-fired power-plants, Fuel cell (H2)
Gas –> Heat: PtG as heat storage
- E.g.: H2-/syntethic CH4-fired CHP-/heating plants
Gas –> Traffic: PtG as fuel storage
- E.g.: Electrolysis (H2) + Firscher-Tropsch-synthesis –> E-Fuels in e.g. aviation, shipping; Electrolysis (H2) + fuel cell/GT
Power –> Traffic:
- E.g.: Electromobility (BEV)
Describe the potential of hydrogen in the future energy system.
The potential of H2 in the future energy system
-
Carbon free energy carrier
–> H2 can be produced without GHG emissions (renewable electricity + electrolysis) -
Energy storage
–> In contrast to electricity, H2 can be stored much easier
–> Therefore H2 has the potential to function as a seasonal energy storage which balances the fluctuating renewable electricity supply and the spatially variable energy demands -
Sector coupling
–> By coupling the electricity, heat, transport and industry sectors, renewable energies can be brought into sectors, which are difficult to electrify and are currently depending on fossil fuels (e.g. steel, chemistry)
Explain different ways to produce hydrogen as well as the colorsheme of hydrogen
Methods to produce H2
Green H2
- Renewable electricity + H2O –> Electrolysis –> H2 + O2
Grey H2
- Heat + Steam (H2O) + Hydrocarbon (e.g. Natural gas/Methan (CH4)) –> Steam-reformation –> H2 + CO2
Blue H2
- Heat + Steam (H2O) + Hydrocarbon (e.g. Natural gas/Methan CH4) –> Steam-reformation + CCS –> H2 + captured CO2
Turquoise H2
- Heat + Hydrocarbon (e.g. natural gas/methan (CH4)) –> Pyrolysis –> H2 + C (solide carbon)
White H2
- H2 as it occurs naturally (e.g. notable deposits in Africa)
An electrolyzer built next to an open field (ground-mounted) PV plant is given but essential values are missing.
What is are good assumption regarding …
1) … the efficiency of the electrolyzer
2) … the capacity factor of the PV plant
1) Efficiency of electrolyzer = 70 %
2) Capacity factor of the PV plant = 25 %
Why is hydrogen not the solution to all challenges related to the energy transition?
Why is hydrogen not the solution to all challenges related to the energy transition?
Hydrogen has several limitations
- Inefficiency
–> Its production, storage, and conversion back to energy involve high energy losses. - Cost
–> Green hydrogen is still significantly more expensive than fossil fuels or even “grey hydrogen” made from natural gas - Infrastructure needs
–> Transport, distribution, and storage infrastructure is underdeveloped and costly to build. - Limited supply
–> Renewable electricity needed for green hydrogen is already in high demand for direct electrification (e.g., EVs, heat pumps).
Therefore, hydrogen is best used selectively, where direct electrification isn’t feasible.
True or false?
The role of hydrogen in residential heating
- Hydrogen use in residential heating is not considered efficient or practical.
- Heat pumps powered by renewable electricity are far more energy-efficient.
- Using green hydrogen for household heating would waste valuable clean energy.
True!
Which industries are likely to have a demand for hydrogen?
Hydrogen demand is expected in “hard-to-defossilize/decarbonize” sectors, such as:
- Steel production (e.g. H2 as feedstock: replacing coking coal in blast furnaces with hydrogen-based direct reduced iron)
- Chemical industry (e.g., H2 as feedstock in ammonia and methanol production)
- Long-distance freight/mobility (e.g., H2 as fuel or as feedstock for E-Fuels in trucks, aviation, shipping)
These sectors cannot be easily electrified and need high-temperature processes or molecular feedstocks.
1) Which are the countries/regions with the highest hydrogen production potential?
2) Is it probable/desirable from an ecological point of view that parts of the industry concentrate there?
1) Which are the countries/regions with the highest hydrogen production potential?
Regions with abundant and cheap renewable energy are best positioned, including:
- North Africa (e.g., Morocco, Egypt – solar and wind)
- Middle East (e.g., Saudi Arabia – solar)
- Australia (vast solar/wind potential)
- Chile (especially Patagonia – wind)
- Iceland and Norway (hydropower)
- Southern USA
These regions could become global exporters of green hydrogen or its derivatives (like ammonia).
2) Is it probable/desirable from an ecological point of view that parts of the industry concentrate there?
- From an ecological and economic perspective, yes:
- Producing hydrogen where renewable energy is abundant maximizes efficiency and minimizes costs and emissions.
- Importing hydrogen or derivatives (e.g., green ammonia) is likely more sustainable than producing all hydrogen domestically in high-demand countries like Germany.
- However, this raises geo-economic and geopolitical concerns (energy dependence, supply security), which some nations try to counter with domestic production goals.
True or false?
Is the process of decarbonization threatened by economic interests of individuals and nation states, promoting non-green hydrogen “bridge technologies” and insisting on a high share of domestic production instead of producing it how and where it’s most reasonable?
Yes, this is a real risk:
- Lobbying for “blue hydrogen” (from natural gas with carbon capture) or even “grey hydrogen” delays real decarbonization.
- National interests may lead to suboptimal solutions, e.g., insisting on domestic production at high costs and emissions.
- There is tension between climate efficiency and industrial policy/sovereignty.
To stay aligned with the 1.5°C goal, countries must prioritize green hydrogen and enable international cooperation on imports and infrastructure.
True!
True or false?
How realistic is it that the needed transition to hydrogen use in Germany is reached to achieve its decarbonization goals for 2030, 2050 and the actual needed carbon neutrality around 2035?
2030 goals: Difficult, but partial targets may be met if:
- Electrolyzer capacity ramps up
- Imports begin (e.g., from North Africa)
- Industrial pilot projects scale
2050 goals: Achievable if:
- Clear policies and investments continue
- EU-wide hydrogen market matures
- Infrastructure is built coherently
True!
How does Methanation work?
CO2 + H2 –> Catalyst –> CH4 + H20
- CO2 comes from industrial emissions, biogas, or direct air capture
