1. Structural Limitations of Renewable Energy and a New Solution for Electricity Storage: Why Hydrogen Is Needed
Although the share of renewable energy such as solar, wind, hydro, and geothermal is rapidly increasing, the world is encountering a wall called “efficient storage methods” because electricity as an energy form has inherent structural limitations. Electricity disappears if it is not used the moment it is produced, and it has the disadvantage of being difficult to store on a large and long-term scale. In particular, solar and wind have problems such as output volatility, low energy density per unit area, and a mismatch between generation sites and demand centers. This also means that electricity produced with low output suffers greater losses the farther it travels. For example, if high-output electricity produced from a nuclear power plant experiences a 20% loss, low-output renewable electricity can experience losses as high as 40–50%.
ESS (Energy Storage Systems) is used to supplement this, but batteries naturally self-discharge over time, and it is difficult to build ESS at every generation site. In addition, charging and discharging cycles accumulate and reduce performance, long-term seasonal storage is too expensive, and electricity cannot be moved to areas outside the power grid.
The core technology that solves these fundamental problems is the conversion of electricity → hydrogen (P2H, Power-to-Hydrogen). Hydrogen produced through electrolysis at the generation site can be stably stored in the form of chemical energy, and there is no energy loss over time. Also, unlike batteries, hydrogen can be physically transported to areas without power grids, enabling a distributed energy structure.
It can be divided into the following structure:
Energy Production → Electrolysis → Pipeline Transport → Hydrogen Storage → Transport & Utilization
Building this infrastructure is the key link that compensates for the weaknesses of renewable energy.
2. The Core Competitiveness of Hydrogen Energy: Long-Term Storage, Long-Distance Transport, and Its Difference From LNG
The biggest reason hydrogen is receiving attention is that it is the energy source that is most easily converted from electricity. Hydrogen can be produced simply through water electrolysis, and the process of converting it back to electricity through fuel cells or turbines is relatively simple. In contrast, LNG cannot be converted directly from electricity—it requires producing synthesis gas, methane conversion, cooling, and liquefaction, which is a complicated process. LNG’s liquefaction temperature is −162°C, requiring extreme cryogenic engineering, and large amounts of energy must be used for cooling and storage. LNG carriers continuously consume energy to maintain liquefaction temperature and still experience constant boil-off gas, which must be used as fuel to compensate. However, hydrogen can be stored in compressed form or transported by simple physical methods, making it more naturally connected to electricity-based renewable energy systems.
Especially, the fact that “electricity can be converted to hydrogen and hydrogen can be converted back to electricity” is a decisive factor in solving renewable energy’s disadvantages: variability, wasted electricity, and regional supply imbalance. Hydrogen has no self-discharge when stored in compressed form, and it can be freely moved through pipelines, tube trailers, and tanks. These characteristics offer great advantages for national power systems that require long-term, large-scale storage over days, weeks, or even seasons. Particularly in regions where surplus renewable electricity is produced (large solar farms, offshore wind farms), immediately converting excess electricity to hydrogen and transporting it to industrial zones or cities is becoming the standard for future energy infrastructure.
3. The Rise of Ammonia: A More Efficient Storage and Transport Solution Than Liquid Hydrogen
Among hydrogen storage methods, ammonia (NH₃) is the one receiving the fastest attention. The greatest advantage of ammonia is that its liquefaction temperature is −33°C, which is extremely high compared to hydrogen’s. This is significantly higher than LNG’s liquefaction temperature (−162°C), meaning the energy consumed for cooling is greatly reduced, and storage and transportation costs are also significantly lowered. In other words, ammonia is a “liquid carrier” that can safely contain hydrogen and holds a structural cost advantage over LNG.
Ammonia also has higher volumetric energy density in liquid form, making it suitable for large-scale transportation, and existing oil and gas transport infrastructure can be used. This is why many countries are adopting ammonia as the “standard hydrogen carrier.” Additionally, ammonia can be burned directly, and replacing coal with ammonia in power plants can reduce carbon emissions. Since ammonia (NH₃) is composed of nitrogen and hydrogen, separating nitrogen and hydrogen allows nitrogen to be used for fertilizers or other products. LNG, on the other hand, produces CO₂, which requires carbon capture, making it a more expensive energy source.
Thus, ammonia is emerging as a key technology in the hydrogen economy. Compared to liquid hydrogen infrastructure, ammonia has lower construction costs and lower technical hurdles, making large-scale deployment more feasible. Ultimately, ammonia is the form that maximizes the economic efficiency of hydrogen storage and transportation, serving as an essential intermediary in the renewable energy → hydrogen → power generation supply chain.
4. The Complete Structure of the Renewable Energy Era: ESS for Short-Term Storage + Hydrogen and Ammonia for Mid- to Long-Term Storage
Energy systems based on renewable energy cannot be completed by a single technology; they require a combination of various storage and conversion technologies. The most ideal configuration is:
ESS (short-term stabilization) + Hydrogen (long-term storage & industrial use) + Ammonia (large-scale transport & low-temperature liquefaction)
ESS adjusts output fluctuations in minutes and hours to maintain power quality, hydrogen provides long-term chemical energy storage to meet large-scale industrial demand (steelmaking, chemicals, power generation), and ammonia enables cost-effective international hydrogen transport, forming a “global green hydrogen supply chain.”
This combination offsets the weaknesses of a single technology and maximizes overall system efficiency. Surplus renewable electricity is converted into hydrogen and stored, then supplied stably to industrial zones, cities, and power plants. Ammonia-based transoceanic transport overcomes the geographic limitations of hydrogen supply, enabling renewable energy movement anywhere in the world. Therefore, the hydrogen–ammonia energy system is the most realistic alternative for the future energy structure and is a key strategy for achieving carbon neutrality, energy security, and industrial competitiveness simultaneously.