The role of hydrogen in the energy transition
Published:2021-04-28 03:01:04    Text Size:【BIG】【MEDIUM】【SMALL

The unique properties of hydrogen can make it a powerful promoter in the energy transition and help optimize energy supply and storage systems and end applications.


1.Realize large-scale and efficient renewable energy integration


In the energy system, the power supply and demand are not completely matched within a certain period of time, such as between day and night or between summer and winter. The continuous integration of growing intermittent renewable energy until reaching the target level (accounting for more than 40% of the power structure) will increase the demand for operational flexibility. The increase in electrification and the limited storage of electricity will require adequate energy storage solutions, such as upgrading the grid infrastructure, adding flexible backup power generation, and strengthening demand-side management or energy storage technologies.


Hydrogen has huge advantages in these aspects, because it not only avoids the emission of carbon dioxide and particulate matter, but also can be deployed in various places on a large scale. Hydrogen can improve the efficiency and flexibility of the energy system in two ways.


When there is an oversupply of electricity, the excess electricity can be converted into hydrogen through electrolysis of water. The hydrogen produced can be used to provide electricity when the electricity is insufficient, and it can also be used in other industries, such as transportation or industry.


Hydrogen can be converted into a centralized or distributed disposable power source or rechargeable power source. Hydrogen helps to cope with sudden drops in the supply of renewable energy, such as during periods of insufficient sunlight. In addition, hydrogen production by electrolysis can provide auxiliary services to the grid, such as frequency adjustment.


Hydrogen can also be used in specific cogeneration systems in industry and buildings through fuel cells to link heat and electricity. This improves the efficiency of power generation and heating, and improves the flexibility of the entire energy system.


Hydrogen can be used as a long-term energy storage medium.


Hydrogen is one of the best solutions for energy storage. Although batteries or supercapacitors can also provide energy storage, they lack the stable power required to solve seasonal imbalances, and the storage time span is also limited.


Pumped storage provides an alternative to hydrogen for clean, long-term and large-scale energy storage. However, this is not enough to cope with seasonal and local differences in demand. For example, in Germany, energy demand in winter is about 30% higher than in summer, while renewable energy power generation in winter is usually 50% lower than in summer.


At present, hydrogen is still a novel way of energy storage, but more and more large-scale hydrogen-based energy storage demonstration projects are being launched around the world, such as in Denmark, Canada, Japan, and the United States. In addition, storing large amounts of hydrogen underground is an effective industry practice and does not constitute a major technical obstacle. As the share of renewable energy increases, the deployment of hydrogen as a long-term storage solution is expected to accelerate. By then, the cost of hydrogen storage for hydrogen stored in the salt cave is expected to drop to 140 euros/MWh in 2030. This is even lower than the projected cost of pumped storage (approximately €400/MWh in 2030). In Germany, the storage potential of the cave is about 37 billion cubic meters, which is enough to store 110 TWhth of hydrogen, which is expected to meet the storage demand throughout the season.


All in all, hydrogen energy can integrate more intermittent energy sources in the energy system and provide the energy system with flexible operations that urgently need to be solved.


2.Realize energy distribution across countries and regions.


For many reasons, the power system needs to distribute renewable energy to different places. Some countries, such as Japan, cannot rely on wind or solar power well. In some cases, it may be more economical to import renewable energy, for example, to transfer low-cost solar energy from solar belt areas to shaded areas. Since hydrogen and its compounds have high energy density and are easy to transport, they will help to (re)distribute energy flexibly.


Long-distance transmission of electricity will cause energy loss, but pipeline transportation of hydrogen will not. When transporting renewable energy on a large scale and long distances, the advantages of hydrogen make it an economically attractive option, for example, from regions with renewable energy power generation potential (such as the Middle East) to regions with high energy demand (such as Europe). The import of hydrogen may be a long-term strategy aimed at dealing with the start-up period of renewable energy or ensuring adequate energy supply during the winter (renewable energy generates less electricity).


Japan is planning to launch the first technical demonstration of a liquefied hydrogen carrier, which will enter international trade in 2020. Nowadays, hydrogen pipelines and gaseous or liquefied tube trailers are the most common transportation methods. With the increase in hydrogen transportation, transportation costs are expected to drop by 30% to 40% in the next 15 years. Some areas have tested the use of existing gas grids to transport hydrogen, but they have not been applied on a large scale. Leeds is the first city to propose converting natural gas grids to hydrogen grids by 2026.


3.Act as a backup energy source to improve the plasticity of the energy system.


Hydrogen has a high energy density, can be stored for a long time and can be used for variable purposes, making it very suitable for energy buffering and strategic storage.


Today, the reserve capacity of the energy system is approximately 90 EJ (24% of the final annual energy consumption), which is almost entirely owned by fossil energy operators. The council believes that there is no indication that the demand for buffers may be greatly reduced in the future.


However, as consumers and the power sector undergo energy transformation, the use of fossil fuels as backup energy sources may decrease. The most effective backup energy should be a mixture of various end-use energy carriers. This mixture includes fossil fuels, biofuels/biomass/synthetic fuels, and hydrogen.


4.Achieve decarbonized transportation.


Fuel cell electric vehicles (FCEV) play an important role in reducing carbon emissions in transportation. Today, oil dominates transportation demand. Gasoline and diesel account for 96% of total fuel consumption and 21% of global carbon emissions.


High-efficiency hybrid vehicles such as hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles (PHEV) are already reducing vehicle emissions. However, completely decarbonized transportation will require the deployment of zero-emission vehicles, such as hydrogen-powered vehicles (FCEV) and battery electric vehicles (BEV), or their hybrid combination. Technological progress and new travel trends (such as connected cars, autonomous driving technology and shared travel) will affect the relative deployment level and transition speed. Both FCEV and BEV types of electric vehicles use similar and complementary technologies, which are particularly suitable for serving different market segments and customers. In addition to reducing carbon dioxide emissions, they can also improve local air quality and reduce noise.


Fuel cell vehicles have many obvious advantages. First of all, they can travel a long distance (over 500 kilometers) without refueling. This feature is highly praised by consumers. Second, they are similar to existing gasoline/diesel cars and can be charged quickly (3 to 5 minutes), thereby increasing consumer convenience. Third, because the hydrogen storage system (compared to the battery) has a higher energy density. Finally, the FCEV infrastructure can be built on the existing gasoline distribution and retail infrastructure to create cost advantages and retain local jobs and capital assets.


Fuel cell vehicles will appear in all transportation fields. Considering the above advantages, fuel cells are particularly important in the decarbonization of passenger cars, heavy transport vehicles, buses and non-electrified trains. At present, the application of synthetic fuel made of hydrogen in transportation and aviation is also being explored.


For passenger cars, the cost of FCEV is currently higher than that of vehicles with internal combustion engines, and the running cost is already similar to the cost of HEV in Japan. When FCEV reaches large-scale commercialization, we believe that by 2025, the cost of medium to large passenger vehicles can be equalized.


Major automakers are looking for solutions for zero-emission products. FCEV has begun to be commercialized. There are thousands of cars on the market in Europe in Japan and the United States, and hundreds in Europe. In China, the goal is to deploy 50,000 FCEVs by 2025 and 1 million by 2030. Japan plans to deploy 200,000 FCEVs by 2025 and 800,000 by 2030.


Fuel cell vehicles began to penetrate the public and cargo transportation. Although the current market share of FCEV buses is still small (about 500 vehicles worldwide), recent investments show that the transportation industry is increasingly turning to FCEV solutions. For example, Lianyungang Haitong Public Transport (China) plans to produce 1,500 FCEV buses, Europe announced that it will deploy 600 to 1,000 FCEV buses by 2020, and South Korea plans to replace 27,000 CNG buses with FCEV by 2030. Germany recently announced that its first hydrogen-powered trains will start operation in 2017.


Many countries plan to launch important hydrogen infrastructure in the next ten years. South Korea and China are planning to build a hydrogen network, and the goal is to build 830 hydrogen refueling stations by 2025. By 2025, the target total of more than 3,000 hydrogen refueling stations will be enough to provide hydrogen for approximately 2 million FCEVs.


5.Can decarbonize industrial energy consumption.


Today, natural gas, coal, and oil provide energy for industrial processes and therefore generate approximately 20% of global emissions. Industry needs to improve energy efficiency (including waste heat recovery) to reduce energy demand. Steam electrolysis technology can help convert excess heat into hydrogen.


High heat above 400°C is difficult to decarburize. Hydrogen burners can supplement electric heating to generate high amounts of heat, depending on local conditions: given the limitations of their energy system design, certain regions may prefer to use hydrogen technology instead of electricity in industry.


Today, industry uses hydrogen in low-heat heating applications, such as process heating and drying. In the future, the industry may also mix hydrogen burners and fuel cells to meet its needs. Fuel cells have higher efficiency than burners and provide heat and power at the same time, but the deployment of fuel cells still requires a lot of investment. In terms of burners, only the existing equipment needs to be adjusted.


6.Can capture carbon as a raw material for production.


Based on the chemical properties of hydrogen, carbon can be \"trapped\". Today, crude oil has been used as a raw material for the production of industrial chemicals, fuels, plastics and pharmaceuticals. Almost all of these products contain carbon and hydrogen. If carbon capture and utilization technology is widely used, hydrogen can convert the captured carbon into usable industrial raw materials, such as methanol, methane, formic acid or urea.


Research on the use of hydrogen and captured carbon to produce chemical feedstocks is in the R&D stage, and preliminary pilot projects have been launched. Iceland has a geothermal plant in operation, which uses geothermal power to generate hydrogen and then captures the CO2 generated by the geothermal to produce methanol. It is said that not only this methanol production is cost-competitive, but the electricity price is 30 euros/MWh. Germany is combining carbon emitted from steel production with hydrogen made from excess electricity to produce chemicals. The project is still in the conceptual stage and is expected to be widely used within 15 years.


7.It can help decarbonize the heating of buildings.


Heating and hot water supply account for approximately 80% of residential energy consumption. Approximately 50 EJ of energy is used for residential heating, accounting for 12% of global emissions, and hydrogen will become part of the portfolio of decarbonization solutions for heating of buildings.


Building heating can use hydrogen as a fuel or use hydrogen-related technologies, and ideally a combination of the two can be used: hydrogen technologies such as fuel cells can be used as energy converters. It can provide high efficiency for thermal energy and power generation. Hydrogen itself can be used as fuel (it can be pure hydrogen or it can be mixed with gas to partially decarbonize the gas network). If you want to switch to heating based on hydrogen combustion, for houses connected to the natural gas grid, it provides the opportunity to continue to use the existing natural gas grid. With relatively small adjustments and investments, the existing natural gas grid can safely transport a mixture of hydrogen and natural gas. Complete decarbonization requires complete conversion to hydrogen, which is envisioned by the natural gas operator in Leeds, England.


Globally, about 190,000 buildings have used hydrogen-based fuel cell micro-CHP for heating, most of which are located in Japan. By 2030, it is estimated that approximately 5.3 million Japanese households will use fuel cells for cogeneration. The large-scale use of hydrogen-based fuel cell micro-CHP has reduced the price by more than 50%, from US$2.4/watt installed in 2009 to US$1/watt installed in 2014.


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