Research on scenario construction and economic analysis for electric-hydrogen coupling

Driven by the “dual carbon” goal and the construction of a New Power System, hydrogen energy as an electric energy storage medium will play an important role and be applied to each link of the power system in the future, showing the development trend as electric-hydrogen coupling. This paper researches 8 typical application scenarios of hydrogen energy throughout the source, grid, and load of a New Power System, describes their composition and characteristics, and calculates economic indicators using the life cycle method, such as the levelized cost of hydrogen (LCOH). At present, the LCOH is high, and the conditions for large-scale promotion have not been met in the short term. The LCOH shows a linear downward trend with the decrease of renewable energy levelized cost or electrolytic cell cost. The LCOH shows a first rapid and then slow downward trend as the efficiency and utilization hours of hydrogen production equipment increase. Generally, when the equipment efficiency exceeds 90% or the utilization hours exceed 19 hours, the improvement of relevant parameters has little impact on the LCOH. With the further improvement of key parameters, hydrogen production-based electricity will have a certain cost competitiveness in the future.


Introduction
In today's world, the great changes that have not occurred in a century are accelerating, and changes in the climate environment and the turbulence of the international situation are posing serious challenges to the energy society.To cope with the energy problem, more than 130 countries and regions have proposed "zero-carbon" targets, demonstrating the global ambition to accelerate green and low-carbon transformation.China proposed a "dual-carbon" goal in September 2020 [1] and a New Power System in March 2021 [2], pointing out the scientific direction for the low-carbon development of energy and power in the new era [3].The significant feature of the New Power System is that renewable energy sources occupy a dominant position in the power supply structure.Renewable energy sources are characterized by randomness, volatility, and intermittency, which leads to a high demand for systemregulating resources, and a significant increase in the difficulty of balancing the system's wide-range and long-cycle power and electricity, posing a serious threat to the security of the power grid [4][5][6].
Hydrogen energy, as a new type of flexible secondary energy, has the advantages of clean and zero-carbon, long-term storage, flexibility and high efficiency, multi-energy conversion, and abundant applications compared with traditional fossil fuels [7].Accelerating the development of hydrogen energy is an important strategic choice to cope with climate change, realize the zero-carbon goal, guarantee energy security, and promote the sustainable development of society.It is imperative to vigorously develop hydrogen production from renewable energy sources and orderly promote the development of the green and low-carbon hydrogen energy industry [8].According to the China The project mainly includes photovoltaic power generation, transmission lines, hydrogen production from electrolyzed water, hydrogen storage and transmission, etc.The annual hydrogen production scale can reach 20,000 tons.On July 11, 2023, China's first high-altitude photovoltaic hydrogen storage project -Huadian Qinghai Delingha 1 million kilowatts of photovoltaic storage and 3 megawatts of photovoltaic hydrogen production project was officially put into operation and generated electricity.The project can generate 2.2 billion kWh of green electricity annually, save 543,900 tons of standard coal annually, and reduce carbon dioxide emissions by 1.48 million tons.
Hydrogen energy can be applied to all aspects of the new power system, showing the development of electric-hydrogen coupling.In this paper, the electric-hydrogen coupling scenario is constructed according to the principle of two-layer planning from the perspective of "source, network, and load", categorized based on whether it interacts with the public grid and the source of electricity used for hydrogen production.The upper layer is divided into three major scenarios, namely, source-side renewable energy electricity for hydrogen production, network-side hydrogen storage power station, and load-side hydrogen production.A detailed description of each scenario and the main capacity configuration and parameter settings are given below.

Source-side renewable electricity generation of hydrogen
The source-side renewable energy hydrogen generation scenario refers to the coupling of hydrogen generation with renewable energy power generation, realizing the transformation of "renewable energy-electric energy-hydrogen energy".This scenario can be divided into the following three types.the first one is the grid-connected hydrogen generation scenario to smooth the fluctuation of renewable energy, which aims to solve the problem of wind and light abandonment and smooth the fluctuation of renewable energy grid-connected power, and realize the smooth grid-connection of renewable energy, as shown in Figure 1.The second one is the centralized renewable energy self-generation and selfconsumption of hydrogen generation and residual power on-grid scenario, which mainly utilizes the renewable energy power generation to produce hydrogen, and feeds the excess power into the grid, and utilizes the grid when the renewable energy power generation is insufficient.This scenario mainly utilizes renewable energy to generate hydrogen, and the excess power is fed into the grid, which is supplemented by grid power when the renewable energy generation is insufficient.The third one is the renewable energy off-grid electric hydrogen generation scenario, which is a self-built grid with no interaction with the public grid, and the electric hydrogen generation equipment follows the characteristic curve of the renewable energy output.The capacity configuration and main parameters of each scenario of source-side renewable energy hydrogen generation are shown in Table 1.

Grid-side hydrogen energy storage plants
Grid-side hydrogen storage power plant refers to the conversion of renewable energy surplus electricity into hydrogen energy through electrolysis of water to hydrogen technology, realizing largescale, long-cycle, and wide-area energy storage.Grid-side hydrogen storage power station adopts the "electricity-hydrogen-electricity" conversion mode: When electricity consumption is in the low valley, using electrolytic water hydrogen production technology, the electricity will be converted into hydrogen storage; When electricity consumption is at the peak, the stored hydrogen energy will be used to generate electricity using hydrogen fuel cells, which effectively solves the problem of balance of electricity and power in the power system.Hydrogen storage power stations in hydrogen production can also participate in grid auxiliary services to further promote renewable energy consumption, as shown in Figure 2. The capacity configuration and main parameters of the grid-side hydrogen storage power station scenario are shown in Table 2.

Load-side electric hydrogen production
Load-side electric hydrogen production refers to the coupling of electric hydrogen production equipment with distributed power sources, power users, and other electric loads to form new load characteristics.This scenario can be divided into the following four types.The first one is the distributed grid electricity hydrogen production scenario, which utilizes valley electricity and electricity market electricity to produce hydrogen, as shown in Figure 3.The second one is the distributed renewable energy self-consumption and grid electricity joint hydrogen production scenario, which simultaneously utilizes renewable energy and valley electricity to produce hydrogen to achieve complete local consumption of renewable energy, with the insufficient portion of the grid to be supplemented by valley electricity.The third is the distributed renewable energy self-consumption hydrogen production + surplus power on-grid scenario, which makes full use of renewable energy to produce hydrogen, and the excess power is fed into the grid.The fourth one is the distributed renewable energy off-grid hydrogen production scenario, which is a distributed renewable energy selfbuilt grid, with no interaction with the public grid, and the hydrogen production equipment follows the characteristic curve of the renewable energy output.The capacity configuration and main parameters of each scenario of load-side electric hydrogen generation are shown in Table 3.In this paper, eight scenarios of electric-hydrogen coupling are constructed on the three sides of "source, grid, and load", and Table 4 summarizes the scale of electrolysis tanks in the eight scenarios, which is one of the variables in the economic analysis.For the convenience of presentation, Section 4 replaces the name of the scenarios with serial numbers, e.g., "Scenario 1" refers to "Grid-connected electric hydrogen production scenario for smoothing renewable energy fluctuations".

Project life cycle cost components
The whole life cycle of a project consists of five stages: the decision-making stage, the design stage, the implementation stage, the operation and maintenance stage, and the end-of-life recovery.Taking into account the characteristics of hydrogen production and refueling projects, the cost of each stage of the whole life cycle of the project is further decomposed into four parts, i.e., the cost during the construction period, the operation cost, the maintenance cost, and the recovery of the residual value, to obtain the cost decomposition structure of the whole life cycle of the hydrogen production project, as shown in Figure 4. (2) Running costs Running cost refers to the sum of all costs incurred in the process of putting the project into operation at completion, mainly including energy costs, labor costs, and other running costs.
(3) Maintenance costs Maintenance cost refers to the sum of costs incurred in carrying out regular maintenance to ensure the safe and stable operation of equipment and systems during normal operation of the project, mainly including energy costs, labor costs, and other operating costs.
(4) Recovery of residual value Recycling residual value, i.e. scrap recycling cost, refers to the cost of dismantling and cleaning up the materials at the end of the project's useful life and the value gain generated after recycling.Different scrap recycling programs may lead to different recycling residual values, and there are almost no hydrogen production and hydrogenation projects in China that are ready to be dismantled due to the end of their life, so there are no reliable reference data for the time being.Therefore, for the time being, only the salvage value gain is considered without taking into account costs such as asset cleaning fees that are difficult to predict and the impact of future appreciation or impairment.Since the salvage value gain is highly related to the cost of the project during the construction period, the recovery of the salvage value is estimated through the ratio of the salvage value gain to the cost of the construction period.

Project life cycle cost components
Economic analysis is the evaluation of the economic effect of the project, according to whether to consider the time value of money, economic analysis methods can be divided into static evaluation and dynamic evaluation.Static evaluation indexes include static payback period and investment return rate; dynamic evaluation indexes include dynamic payback period, net present value, net annual value, present value of cost, annual value of cost, internal rate of return, and net present value index, as shown in Figure 5.The dynamic evaluation method not only takes into account the time value of money but also considers all the economic data of the project during its entire life.Therefore, dynamic evaluation indicators are more comprehensive and scientific than static evaluation indicators.

Levelized unit cost estimation model for electrohydrogen coupling projects
Levelized cost indicators are widely chosen for the deterministic evaluation of the economic effects of energy projects.Levelized cost analysis is a dynamic evaluation method that measures the average cost of a project's products by discounting the costs and expenses of the entire life cycle of the project and the output of the project's products to the current period under the opportunity cost of the industry's average social return on investment.
In the electric-hydrogen coupling project, the time value of money is taken into account to construct a levelized unit cost estimation model for the whole life cycle of the project, as shown in Equation (1): where LCOH (levelized cost of hydrogen) refers to the full life-cycle levelized unit cost of hydrogen, CAPEX refers to the construction cost, OPEX refers to the operation and maintenance cost, CR refers to the electrolyzer replacement cost, VR refers to the salvage value return, QH2_yr refers to the annual amount of hydrogen production, N refers to the project operation period, and r refers to the social discount rate.The equation for calculating CAPEX is shown below: where Cland refers to the cost of land and plant, Ck refers to the acquisition and installation cost of the equipment used, and the main equipment related to the electricity-hydrogen coupling project includes wind-solar renewable energy field station equipment, transmission and distribution equipment, batteries, electrolyzers, and hydrogen storage tanks, and Cother1 refers to other costs, including the project management costs, technical service fees, and so on.
In addition, the OPEX calculation equation is shown below:

OPEX C C C
(3) where Ce refers to the cost of electricity consumption, Cw refers to the cost of water consumption, and Cother2 refers to other operation and maintenance costs, including labor and overhead.

Conditions for cost analysis of electrohydrogen coupling projects
Taking the capacity configuration method of an electric hydrogen production demonstration project in Qinghai as a reference, and combining the application characteristics of hydrogen energy in the "source, network and load" segments of the new electric power system, based on the 100 MW alkaline electrolyzer, we configure the capacity of each piece of equipment in the electric hydrogen production system under different scenarios, and carry out the analysis of the levelized unit cost of electric hydrogen production in various scenarios.The assumptions of the analyzing process are shown in Table 5.
Table 5. Conditions for cost analysis of electrohydrogen coupling projects.

Economic analysis for each scenario
This section discusses the decreasing trend of the cost of electric hydrogen production in each typical scenario from 2020 to 2060, and based on this, analyzes the influencing factors of the levelized cost of electric hydrogen production in each typical scenario based on the Probit-AISM model, generalizes each influencing factor to different topological levels, and then obtains the comprehensive main influencing factors, as shown in Figure 6. Figure 6 analyzes the influencing factors of the levelized cost of electric hydrogen production, summarizes the basic influencing factors into comprehensive influencing factors, and obtains four important influencing factors that have an impact on the levelized unit cost of electric hydrogen production under each typical scenario.The four influencing factors include cost per kWh of renewable energy electricity, cost of electrolyzer, efficiency of electrolyzer, and daily utilization rate of electric hydrogen production equipment.This paper carries out the sensitivity analysis of the above four influencing factors to study the degree of their influence on the cost of electric hydrogen production under each scenario.

Comprehensive cost analysis of electric hydrogen production
Taking into account factors such as the decline in cost per kWh of renewable energy electricity, the decline in cost of the electrolyzer, the decline in the efficiency of the electrolyzer, and the increase in the daily utilization rate of the electric hydrogen production equipment, the decreasing trend of the cost of electric hydrogen production from 2020 to 2060 for each typical scenario has been analyzed and is shown in Figure 7.As can be seen in Figure 7, except for Scenarios 4 and 5, the source-side and load-side scenarios (Scenarios 1-3 and Scenarios 6-8) that utilize renewable energy to generate hydrogen are more affected by changes in the price of green power, and the cost of electricity to produce hydrogen decreases faster over time.Scenario 2 (source-side self-generated hydrogen production + residual power on-grid and off-grid electricity hydrogen production scenarios) is more economical, hydrogen cost always remains low from 2020 to 2060 and is expected to be lower than 10 yuan/kg after 2060, close to the current gray hydrogen price, with a certain degree of cost competitiveness.Scenario 1 (grid-connected electricity hydrogen production scenario to smooth the fluctuation of renewable energy) has low utilization hours for hydrogen production equipment and higher hydrogen production costs in the early stages of development, at about 34 yuan/kg, but the cost of hydrogen production under this scenario declines faster, and the cost of hydrogen production will be lower than that of Scenario 4 (hydrogen energy storage power plant) and Scenario 5 (distributed grid-connected electricity hydrogen production scenario) after 2040 and 2050, and the cost of hydrogen production will be as low as about $18 in 2060 and the economy of this scenario has some room for improvement in the future.Load-side distributed electricity hydrogen production scenarios (Scenarios 5-8) are smaller in capacity, the scale effect is not obvious, its economy has some room for improvement in the future, and it is expected to realize large-scale development and become an important part of the grid's flexibility regulation resources, providing a new means of regulating grid operation.

Impact of the cost of renewable energy kWh
First, the impact of renewable energy generation unit cost on the levelized unit cost of electric hydrogen production is discussed.Assuming that the cost of the electrolyzer is 1800 yuan/kW and the efficiency of the electrolyzer is 0.71, the trend of the cost of electrohydrogen production with the renewable energy electricity tariff in each scenario is shown in Figure 8.  Figure 8 shows very clearly two types of trends in the cost of electric hydrogen production in response to changes in renewable energy tariffs.One category is that the change in renewable electricity price has basically no effect on the levelized unit cost of electric hydrogen production, including scenarios 4 and 5, i.e., the grid-side hydrogen storage plant scenario and the load-side distributed grid hydrogen production scenario.In these two types of scenarios, renewable energy power generation is firstly integrated into the public grid or distributed grid, and renewable power is not used for direct hydrogen production, valley power and power market power are used for hydrogen production, so the renewable energy unit cost has basically no impact on the cost of electric hydrogen production.The other category is that the levelized unit cost of electricity for hydrogen production has a basically linear relationship with the price of renewable electricity, including scenarios 1-3 and scenarios 6-8, i.e., scenarios in which renewable electricity is used for direct hydrogen production.In these scenarios, the renewable energy unit cost has a large impact on the cost of green hydrogen, e.g., for every decrease in renewable energy unit cost by 0.10 yuan/kWh, the cost of electric hydrogen production decreases by about 5.60 yuan/kg; for a decrease in renewable energy unit cost from 0.50 yuan/kWh to 0.10 yuan/kWh, the cost of electric hydrogen production decreases by about 22.40 yuan/kg.Therefore, reducing the cost of renewable energy unit cost by technological upgrades can be significantly reduced.Renewable energy cost of electricity can significantly reduce the unit cost of green hydrogen, such as vigorously developing remote high-voltage DC transmission technology, energy storage technology, and load-side flexible response technology.

Impact of electrolyzer costs
Next, the effect of electrolyzer costs on the levelized unit cost of electric hydrogen production is discussed.Assuming that the unit cost of wind power is 0.28 yuan/kWh, the unit cost of photovoltaic is 0.21 yuan/kWh, and the efficiency of the electrolyzer is 0.71, the trend of the cost of electrohydrogen production with the cost of the electrolyzer in each scenario is shown in Figure 9. Figure 9 shows that the levelized unit cost of electric hydrogen production is basically linearly related to the electrolyzer cost.Among them, the decreasing trend of electric hydrogen production cost with the change of electrolyzer cost is more obvious in Scenario 1 and Scenario 8, and the cost of electric hydrogen production decreases by about 3.50 yuan/kg for every decrease of 1000 yuan/kW in the electrolyzer cost.In this case, the cost of electric hydrogen production is 26.15 yuan/kg; when the electrolyzer cost is 1,000 yuan/kW, the cost of electric hydrogen production is 21.96 yuan/kg.The cost of electric hydrogen production under the scenarios changes slowly, and for every 1,000 yuan/kW decrease in the electrolyzer cost, the cost of electric hydrogen production decreases by 1 yuan/kg.Therefore, under the conditions of similarity of other capacity configurations and main parameters, and high electrolyzer cost, the construction of the Distributed Renewable Energy Self-Generation Selfuse hydrogen production + waste electricity on-grid scenario obtains the lowest cost of hydrogen energy.From the discussion in this section, it can be seen that reducing the cost of the electrolyzer can effectively reduce the cost of electric hydrogen production, such as developing high-efficiency catalyst materials, reducing the thickness of the diaphragm, and improving the operating conditions and structure of the electrolyzer.Currently, the cost of an alkaline electrolyzer is about 1800 yuan/kW, which has limited space for cost reduction, but the cost of a proton exchange membrane electrolyzer is higher, which is about 5200 yuan/kW, and still has large space for cost reduction, which in turn reduces the cost of electric hydrogen production in each typical scenario.

Effect of electrolyzer efficiency
Subsequently, the effect of electrolyzer efficiency on the levelized unit cost of electric hydrogen production is discussed.Assuming that the unit cost of wind power is 0.28 yuan/kWh, the unit cost of photovoltaic is 0.21 yuan/kWh, and the cost of the electrolyzer is 1800 yuan/kW, the trend of the cost of electric hydrogen production with the efficiency of the electrolyzer in each scenario is shown in Figure 10. Figure 10 shows that as the efficiency of the electrolyzer increases, the decreasing trend of the levelized unit cost of hydrogen production shows a fast and then slow pattern.When the efficiency of the electrolyzer is increased from 10% to 30%, the cost of hydrogen production is reduced by 70.94 ~ 66.64%; when the efficiency of the electrolyzer is increased from 30% to 50%, the cost of hydrogen production is reduced by 48.84 ~ 39.94%; when the efficiency of electrolyzer is higher than 50% and is increased again, the cost of hydrogen production does not have a significant decreasing trend, for example, when the efficiency of electrolyzer is increased from 90% to 100%, the cost of hydrogen production is reduced only by about 10%.Among the typical scenarios discussed in this paper, Scenario 5 (Distributed Grid Electric Hydrogen Generation Scenario) shows the most significant decrease in the cost of electric hydrogen production with the increase in electrolyzer efficiency.In the whole range of electrolyzer efficiencies, Scenario 7, i.e., Distributed Renewable Energy Self-Generated Hydrogen Production + Waste Electricity Grid Electricity Scenario, has the lowest cost of electric hydrogen production, which is in line with the conclusion on the impact of electrolyzer costs in Section 4.3.Therefore, in practical applications, when the electrolyzer efficiency is low, the cost of electric hydrogen production can be significantly reduced by upgrading the electrolyzer efficiency; when the electrolyzer efficiency is high, the cost of electric hydrogen production is limited by upgrading the electrolyzer efficiency, and materials research and development, system integration and other methods can be synthesized to improve the economy of the system.

Impact of daily utilization hours of electric hydrogen production equipment
Next, the effect of daily utilization hours of electric hydrogen production equipment on the levelized unit cost of electric hydrogen production is discussed.Assuming that the wind power unit cost is 0.28 yuan/kWh, the photovoltaic unit cost is 0.21 yuan/kWh, the electrolyzer cost is 1800 yuan/kW, and the electrolyzer efficiency is 0.71, the trend of the cost of electric hydrogen production with the number of daily utilization hours of the electric hydrogen production equipment in each scenario is shown in Figure 11.Equipment utilization rate/h day -1 Levelized unit cost of H2 by electricity/yuan kg -1 Figure 11 shows that the levelized unit cost of hydrogen production decreases rapidly at first and then decreases gently as the number of daily utilization hours of the hydrogen production equipment increases.Among them, when the utilization hours of electric hydrogen production equipment are extended from 4 hours/day to 9 hours/day, the cost of electric hydrogen production decreases by 40.03 ~ 34.70%; while when the utilization hours of electric hydrogen production equipment are extended from 19 hours/day to 24 hours/day, the cost of electric hydrogen production decreases by less than 10%.According to statistics, the utilization hours of inland wind power are about 2000 ~ 2500 hours/year globally, the utilization hours of offshore wind power are less than 2000 hours/year, and the utilization hours of photovoltaic power generation are about 1000 ~ 2000 hours/year.Relying only on a single type of renewable energy to produce hydrogen, the equipment utilization hours are low, and the utilization hours of electric hydrogen production equipment can be extended to 14 ~ 19 hours/day through the optimal allocation of wind and solar complementary to improve the economy of electric hydrogen production.However, relying only on indirect and fluctuating renewable energy sources cannot satisfy the daily utilization rate of the electric hydrogen production equipment to be 24 hours/day, and the further extension of the daily utilization time does not have a significant impact on the effect of reducing the cost of electric hydrogen production.It is not economically feasible to supplement the daily utilization of the hydrogen generation equipment with higher-cost non-renewable energy sources, such as nuclear power or electricity from the public grid, and therefore it is not necessary to extend the daily utilization of the hydrogen generation equipment to its limit.

Conclusion
This paper makes full use of the complementary characteristics of wind and light renewable energy sources, analyzes in detail the impact of the configuration of each parameter on the levelized unit cost of electric hydrogen production for the characteristics of each typical application scenario, and discusses the cost changes of electric hydrogen production in a more distant time frame by integrating various factors.On the basis of this paper, further research on the optimal configuration of the economics of the electric hydrogen production system.Analysis has found that the unit cost of hydrogen production from electricity is relatively high at the current stage, and the conditions for large-scale promotion have not yet been met in the short term.The cost of hydrogen production from electricity shows a linear downward trend with the decrease in renewable energy costs and electrolytic cell costs.The cost of hydrogen production from electricity shows a decreasing trend from fast to slow as the efficiency and utilization hours of hydrogen production equipment increase.When the equipment efficiency exceeds 90% and the utilization hours exceed 19 hours, the improvement of relevant parameters has little impact on the cost of hydrogen production.In the future, with the further improvement of key technologies, the unit cost of renewable energy electric hydrogen production can be reduced and the development of clean hydrogen energy industry can be promoted.

Figure 1 .
Figure 1.Grid-connected electric hydrogen production scenario for smoothing renewable energy fluctuations.

Figure 2 .
Figure 2. Scenario of grid-side hydrogen energy storage plant.

Figure 3 .
Figure 3. Scenario of distributed grid power hydrogen production on the load side.

Figure 4 .
Figure 4. Project Life Cycle Cost Components.(1)Construction period costs Construction period cost refers to all the construction costs spent during the preparation and construction of the hydrogen production project, mainly including the cost of equipment purchase, the cost of installation works, the cost of construction works, and other investment costs.(2)Running costs Running cost refers to the sum of all costs incurred in the process of putting the project into operation at completion, mainly including energy costs, labor costs, and other running costs.(3)Maintenance costs Maintenance cost refers to the sum of costs incurred in carrying out regular maintenance to ensure the safe and stable operation of equipment and systems during normal operation of the project, mainly including energy costs, labor costs, and other operating costs.(4)Recovery of residual value Recycling residual value, i.e. scrap recycling cost, refers to the cost of dismantling and cleaning up the materials at the end of the project's useful life and the value gain generated after recycling.Different scrap recycling programs may lead to different recycling residual values, and there are almost no hydrogen production and hydrogenation projects in China that are ready to be dismantled due to the end of their life, so there are no reliable reference data for the time being.Therefore, for the time being, only the salvage value gain is considered without taking into account costs such as asset cleaning fees that are difficult to predict and the impact of future appreciation or impairment.Since the salvage value gain is highly related to the cost of the project during the construction period, the recovery of the salvage value is estimated through the ratio of the salvage value gain to the cost of the construction period.

Figure 5 .
Figure 5. Indicators for evaluating the economics of projects.

Figure 6 .
Figure 6.Indicators for evaluating the economics of projects.

Figure 7 .
Figure 7. Trend of decreasing cost of electric hydrogen production by scenario from 2020 to 2060.

Figure 8 .
Figure 8. Trend of electric hydrogen production cost with renewable energy kWh cost by scenario.

1 Figure 9 .
Figure 9. Trend of electric hydrogen production cost with electrolyzer cost in each scenario.

Figure 10 .
Figure 10.Trend of electric hydrogen production cost with electrolyzer efficiency in each scenario.

Figure 11 .
Figure 11.Trend electric hydrogen production cost with electric hydrogen production equipment utilization hours in each scenario.

Table 1 .
Capacity configuration and main parameters of each scenario of electric hydrogen production from renewable energy sources at the source side.

Table 2 .
Scenario capacity configuration and main parameters of grid-side hydrogen storage plant.

Table 3 .
Capacity configuration and main parameters of each scenario of electric hydrogen production on the load side.

Table 4 .
Electro-hydrogen coupling scenarios and hydrogen production scales.