Under which conditions, green hydrogen does better than batteries ?
Green hydrogen has unique advantages over batteries in specific scenarios, particularly where long-term energy storage, scalability, and grid-scale storage are concerned. Here’s a breakdown of the conditions under which green hydrogen excels and additional insights into related topics:
Conditions Favouring Green Hydrogen Over Batteries
- Long-Duration Energy Storage: Green hydrogen is more effective for long-term energy storage needs, particularly for durations beyond what batteries can economically or efficiently handle. While lithium-ion batteries are well-suited for short-duration storage (hours to a day), green hydrogen can store energy for weeks or months, making it ideal for seasonal storage to balance supply and demand over longer periods.
- Energy Density: Hydrogen has a higher energy density by weight than batteries, making it more suitable for applications requiring high energy content over long distances or durations, such as in aviation, shipping, or long-haul trucking.
- Scalability and Flexibility: The storage capacity of green hydrogen systems can be scaled up simply by increasing the size of hydrogen storage tanks, which is a more straightforward process than scaling battery storage capacity. This scalability makes green hydrogen a viable option for large-scale energy storage and heavy industrial applications.
- Grid Stabilization and Decarbonization: For grid-scale energy storage, green hydrogen can play a significant role in stabilizing the grid over longer periods of low renewable energy generation. It can also help decarbonize sectors that are difficult to electrify directly, such as certain industrial processes, by providing a clean fuel alternative.
Green Hydrogen for Long Term Energy Storage
Green hydrogen serves as an excellent option for long-term energy storage by converting excess renewable energy into hydrogen through electrolysis. This hydrogen can be stored indefinitely and then converted back to electricity through fuel cells or used directly as fuel when needed. This capability is particularly valuable for addressing the variability of renewable energy sources and ensuring a reliable energy supply throughout the year.
Scalability of Green Hydrogen Storage
The scalability of green hydrogen storage is one of its key advantages. Unlike batteries, where scaling up requires additional complex systems and significant materials, scaling hydrogen storage involves increasing the size or number of hydrogen storage tanks. This scalability makes it possible to store large quantities of energy, supporting the integration of renewable energy sources into the energy mix at a much larger scale.
Grid Scale Green Hydrogen Storage
At the grid scale, green hydrogen storage can act as a massive reservoir of clean energy that can be tapped into to meet demand during periods of low renewable energy production. This capability is critical for enhancing grid reliability and flexibility, allowing for higher penetration of intermittent renewable energy sources like wind and solar power. Green hydrogen can be generated during periods of excess renewable energy, stored for days, weeks, or even months, and then utilized when demand exceeds supply, making it a cornerstone for a sustainable, decarbonized energy system.
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GREEN HYDROGEN VS BATTERIES – A COMPARISON
- Efficiency:
- Electrolysis efficiency: Commercial electrolyzers typically have efficiencies ranging from 60% to 80% for alkaline electrolyzers and 70% to 90% for proton exchange membrane (PEM) electrolyzers.
- Battery charging and discharging efficiency: Lithium-ion batteries, the most common type of battery, have round-trip efficiencies ranging from 80% to 90%.
- Energy Density:
- Hydrogen energy density: Hydrogen has an energy density of about 120-142 MJ/kg (megajoules per kilogram) when compressed at high pressure or liquefied at low temperature. As a gas at room temperature and pressure, its energy density is much lower.
- Lithium-ion battery energy density: Lithium-ion batteries typically have energy densities ranging from 150 to 250 watt-hours per kilogram (Wh/kg).
- Cost:
- Electrolyzer cost: The cost of electrolyzers varies depending on factors such as size, technology (alkaline or PEM), and production volume. As of 2022, the cost of electrolyzers ranges from $500 to $1,000 per kilowatt (kW) of capacity.
- Battery cost: The cost of lithium-ion batteries has been declining steadily in recent years. As of 2022, the average cost of lithium-ion batteries is around $150 to $200 per kilowatt-hour (kWh) of storage capacity.
- Deployment:
- Global installed electrolyzer capacity: The global installed capacity of electrolyzers for hydrogen production was approximately 600 megawatts (MW) in 2020, with projections to reach several gigawatts by 2030.
- Global installed battery storage capacity: The global installed capacity of grid-scale battery storage systems reached over 20 gigawatt-hours (GWh) in 2020, with significant growth expected in the coming years.
- Renewable Energy Integration:
- Renewable hydrogen production: Electrolysis powered by renewable energy sources accounted for a small but growing share of global hydrogen production in 2020, with estimates ranging from 1% to 5%.
- Renewable energy storage: Batteries are widely used for storing excess renewable energy generated from sources like solar and wind power. The global installed capacity of battery storage systems connected to renewable energy projects exceeded 20 GWh in 2020.
TOP UNIVERSITY RESEARCH PROJECTS ON THIS:
Regarding the top university projects on this topic, it’s essential to note that research in this field is continually evolving, and new projects emerge regularly. However, some notable university projects focusing on green hydrogen technologies and their comparison with batteries include:
- ETH Zurich – SCCER Mobility Project: This project focuses on the development of hydrogen fuel cell technologies for various applications, including transportation and stationary power generation. The research includes comparative studies on the performance and efficiency of hydrogen fuel cells versus battery technologies.
- Stanford University – Global Climate and Energy Project (GCEP): Stanford’s GCEP includes research on sustainable energy technologies, including hydrogen production and storage. Projects within GCEP investigate the economic and environmental implications of using green hydrogen compared to batteries for energy storage and transportation.
- Massachusetts Institute of Technology (MIT) – Energy Initiative: MIT conducts research on various energy technologies, including hydrogen fuel cells and batteries. Projects within MIT’s Energy Initiative assess the technical and economic feasibility of using green hydrogen versus batteries in different applications, such as grid-scale energy storage and transportation.
- Technical University of Denmark (DTU) – Hydrogen and Fuel Cells Center: DTU’s center focuses on research and development of hydrogen and fuel cell technologies. Projects within the center explore the performance, cost, and sustainability aspects of green hydrogen compared to batteries, particularly in the context of renewable energy integration and decarbonization efforts.
Specific Challenges:
While green hydrogen holds promise as a clean energy carrier, it faces specific challenges compared to batteries in certain scenarios. One major challenge is the efficiency of electrolysis, the process of splitting water into hydrogen and oxygen using electricity. Electrolysis processes typically have lower efficiency rates compared to battery charging and discharging cycles, leading to higher energy losses.
Additionally, the infrastructure required for green hydrogen production, storage, and distribution is still underdeveloped and costly compared to battery storage systems. This includes the construction of electrolyzers, hydrogen storage tanks, and transportation infrastructure. As a result, the initial capital investment for green hydrogen infrastructure can be prohibitive in some cases.
Furthermore, the energy density of hydrogen is lower than that of batteries, meaning larger storage tanks or facilities are needed to store equivalent amounts of energy. This can be a limitation in applications where space is limited or where mobility is a key consideration.
Case Study: In remote or off-grid locations with abundant renewable energy resources but limited access to the electricity grid, green hydrogen can be a more viable energy storage solution compared to batteries. For example, a remote island community may use excess renewable energy to produce green hydrogen through electrolysis and store it for later use in fuel cells to generate electricity when solar or wind power is unavailable.
PERSPECTIVES OF GLOBAL EXPERTS
The perspectives of global experts on the comparison between green hydrogen and batteries vary depending on the specific context, application, and technological advancements:
- James Richardson, Chief Economist at Westminster Energy Forum:
“Hydrogen can give you high temperatures; that it can act as a chemical reducing agent; and that it’s easy to store in large-scale static environments. It is a lot more energy dense than batteries. Those are all useful properties.
But we also know that low carbon hydrogen is a pretty expensive fuel. You make it either from natural gas combined with carbon capture and storage or electricity, so the laws of thermodynamics make it more expensive than natural gas or electricity.”
- “To decarbonise the transport sector by 2035, we need both technologies on the market – affordable, reliable and safe. For me, these are the two pillars of future mobility”. – Pascal Mast, Director of Sustainable Technology at TÜV SÜD Mobility
CONCLUSION
Overall, green hydrogen may outperform batteries in scenarios where long-duration energy storage, grid-scale applications, or off-grid solutions are required, despite facing specific challenges related to efficiency, infrastructure, and energy density. Ongoing research and technological advancements aim to address these challenges and further optimize the utilization of green hydrogen as a clean and sustainable energy carrier.
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