摘要 | ��
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1. Research Purpose
Although the transition from carbon economy based on fossil fuel to hydrogen economy is necessary to address the energy security and climate change problems, the introduction of hydrogen energy is expected to entail substantial costs compared to fossil energy. Thus, in order to pursue the transition to hydrogen economy while achieving lasting economic growth, there is a special need to perform the sound research for establishing foundations to prepare for the future hydrogen economy.
This research, which will be done over three years from 2009 to 2011, mainly aims to develop policy alternatives for the transition to hydrogen economy. In the first year(2009), we will focus on analyzing the effects on primary energy demand due to the introduction of hydrogen energy. In addition, the effect on green house gas emission will be analyzed because the introduction of hydrogen energy is expected to have an influence on green house gas emission through substituting fossil fuel. As the cost of the hydrogen energy is expected to be higher than that of the current fossil fuel, the change of cost due to the introduction of hydrogen energy is also discussed. The period for the analysis is from 2005 to 2050 and all costs are valued on the basis of constant price in 2005.
2. Summary
Total primary energy demand in 2050 is estimated as 352.0 million TOE and this is expected to grow at an average rate of 1.1% per annum since 2005. As the demands for renewable energy(CAGR, 11.5%), nuclear power(CAGR, 1.9%), LNG(CAGR, 1.3%), coal (CAGR, 1.0%) and oil(0.4%) are increasing, the market shares of LNG, nuclear energy, renewable energy are expected to increase. As a result, the share of clean energy is to be increased under BAU without hydrogen.
We set twelve hydrogen scenarios by mixing three alternatives of demand side and four alternatives of supply side. The demand side alternatives are classified as a baseline demand, high demand, low demand according to hydrogen demand, and the supply side alternatives are classified as the activation by renewable energy sources, the activation by coal, the activation by LNG, and the introduction of nuclear power.
Under the baseline scenario, hydrogen energy will be firstly introduced from 2015 and reach 5% market share in 2030. The hydrogen demand is expected to reach 12.19 Million Ton in 2050 from 1,600 Ton in 2015. Under high demand scenario, the timing of 5% market share will be advanced from 2030 to 2025, but the hydrogen energy demand in 2050 may be similar to that under the baseline scenario because the demand is expected to be saturated around 2050. Under low demand scenario, hydrogen energy will be firstly introduced from 2018 and reach 5% market share in 2035. The hydrogen demand is expected to reach 11.61 Million Ton in 2050.
In hydrogen supply scenarios, the activation by renewable energy sources represents the scenario in which the main source of hydrogen supply is renewable energy. The activation by coal means that the production of hydrogen mainly depends on coal compared to other scenarios. The activation by LNG is the scenario in which the hydrogen production using LNG substitutes a part of the hydrogen production using the renewable energy. While other scenarios exclude the hydrogen production from nuclear power, the scenario for the introduction of nuclear power considers hydrogen production from nuclear power.
We assume that nuclear hydrogen is produced by combined ways of High Temperature Gas Nuclear Reactor and three hydrogen production processes using nuclear power (Sulfur-Iodine process, Hybrid-Sulfur(HyS) process, High Temperature Electrolysis process). The hydrogen production from coal supposes IGCC technology. The hydrogen production from natural gas is divided by the hydrogen production using centralized method and decentralized method, and the hydrogen production by the renewable energy assumes the production by solar energy, wind power and biomass. The existing research says that the unit cost of nuclear hydrogen production will be $2.26~2.46/kg-H2. Also, the unit cost of hydrogen production from solar energy is around $10 and that from wind power is around $3, in case of biomass $2.2, in case of coal $1.429~$1.622(with or without CCS), in case of natural gas $2.7~7.2.
This research adopts a MARKAL model using a bottom-up optimization method. This is the model which selects the energy system satisfying the final demand with the lowest cost under the energy supply & demand conditions and environmental constraints. The objective function is the cost function which includes technology investment cost, fixed maintenance cost, variable maintenance cost, fuel cost and residual values and etc. All energy supply & demand equilibrium conditions including electricity and heat etc, and pollutant emissions allowances are included as constraints. The endogenous variables determined within the model are export and import level of primary energy, domestic production(supply), various technology investment level(resources technology, transfer technology, manufacturing technology and supply technology, etc.), facility capacity, activity level and pollutant emission level etc.
We assume that hydrogen is used in transport sector, household & commercial sector, and power generation sector. In case of the transport sector, fuel cell car is introduced, in case of household & commercial sector and power generation sector, fuel cell for power generation is introduced.
In the baseline hydrogen scenario, the analysis shows that the primary energy demand decreases from -0.6% to -7.1% in 2050 compared to BAU without hydrogen energy. It is analyzed that the activation scenario by renewable energy shows the least energy consumption reduction(-0.6% in 2050 compared to BAU) and the nuclear hydrogen scenario shows the most energy consumption reduction(-7.1% in 2050 compared to BAU).
As for energy sources, it is analyzed that although the demands for coal, oil, hydro power and nuclear power decrease, the demands for LNG and renewable energy increase. It is evaluated that the decrease of coal consumption is mainly affected by the decrease of coal consumption in power generation sector accompanying by decrease of electricity demand through the introduction of fuel cell to household & commercial sector and power generation sector. The decrease of the consumption of gasoline, diesel and butane due to the introduction of fuel cell car takes effect on the decrease of the oil consumption. In case of hydro power and nuclear power, it is shown that the decrease of electricity consumption takes effects on the decrease of the demands for hydro power and nuclear power. The increase of LNG demand may be explained mostly by the increase of LNG demand for hydrogen production and the increase of renewable energy demand is also evaluated to come from the increase of the demand for hydrogen production.
This study shows that the energy demands in transport, household & commercial sector decrease but the energy demands in industry and public sector, in which hydrogen energy is not introduced, is not changed. In case of the decrease rate of energy demand, the decrease rate in transport sector is the greatest and that in household & commercial sector is the second highest. This is why the decrease effect by the introduction of fuel cell car appears large in transport sector.
It is analyzed that greenhouse gas emission decreases from -6.3% to -18.5% in 2050. The activation scenario by coal shows the lowest decrease effect of green house gas emission(-6.3% in 2050 compared to BAU) and the nuclear hydrogen scenario shows the greatest decrease effect in green house gas emission(-18.5% in 2050 compared to BAU). The reason why the decrease effect in greenhouse gas emission is larger than that in energy consumption is that low carbon fuel is mainly used.
The analysis shows that the total energy system cost in Korea under the baseline hydrogen scenario(including energy cost, capital cost, operation cost) is at least 0.22% and at most 0.49% higher in 2050 compared to the case of non-introduction of hydrogen energy. It is estimated that the cost in the nuclear hydrogen scenario will increase the least(0.22% increase compared to the baseline scenario in 2050) and the cost in the activation scenario by LNG scenario will increase the largest(0.49% increase compared to the baseline scenario in 2050).
In case of high demand scenario for hydrogen, it is estimated that the primary energy demand decreases from -0.9% to -7.4% in 2050. As with the baseline hydrogen scenario, the decrease level of energy consumption in the activation scenario by renewable energy is largest and that in nuclear hydrogen scenario is lowest. However, the decrease rate in the high demand scenario is slightly higher compared to the baseline hydrogen scenario. The direction of demand change by energy sources is also the same with the baseline hydrogen scenario, but the decrease rate of the demand for coal, oil, hydro power, nuclear power and the increase rate of of the demand for LNG and renewable energy is higher than the baseline hydrogen scenario.
It is analyzed that greenhouse gas emissions under high demand hydrogen scenario will decrease from -6.2% to -18.4% in 2050. It is expected that the direction of the change of greenhouse gas emissions is the same with the baseline hydrogen scenario but the decrease rate of greenhouse gas emissions will increase further compared to that under the baseline hydrogen scenario. The total system cost in Korea under high demand hydrogen scenario(including energy cost, capital cost, operating cost, etc.) is analyzed to grow the minimum 0.44%, the maximum 0.53% in 2050 compared to non-introduction of hydrogen energy. It appears that the decrease direction under both scenarios is similar but the increase size of system cost appears to be higher in the high demand hydrogen scenario.
In case of low demand scenario for hydrogen, it is estimated that the primary energy demand decreases from -1.0% to -6.8% in 2050. Compared to the baseline hydrogen scenario, the structure such as the direction of energy consumption is same, but the decrease rate of energy consumption is slightly lower. The direction of demand change by energy sources is also the same with the baseline hydrogen scenario, but the decrease rate of the demand for coal, oil, hydro power, nuclear power and the increase rate of the demand for LNG and renewable energy is higher than the baseline hydrogen scenario. The energy demand by sectors has the same direction with the baseline hydrogen scenario but the decrease rate of the energy demand in low demand hydrogen scenario is lower than that of the baseline hydrogen scenario.
It is analyzed that greenhouse gas emissions under low demand hydrogen scenario will decrease from -6.0% to -17.3% in 2050 compared to that under non-introduction scenario of hydrogen energy(BAU). Compared to the baseline hydrogen scenario, the decrease effect of greenhouse gas emissions is analyzed to be slightly lower than that under the baseline hydrogen scenario. It is expected that the increase size of total domestic system cost is also reduced compared to the baseline hydrogen scenario.
3. Research Results and Policy Suggestions
In case of the baseline hydrogen scenario, the primary energy demand is observed to decrease, and also the greenhouse gas emissions is tobe declined in 2050 compared to BAU. However, it is expected that there will be a countervailing effect that the energy system cost increase despite some positive effects that the energy consumption and greenhouse gas emissions decrease.
Thus, the cost minimization due to the introduction of hydrogen seems to be a top priority for the successful transition to hydrogen economy. The government investment in research & development for hydrogen production technology needs to be accelerated and policy supports for introducing hydrogen energy to market are necessary. It is expected that the competitiveness of hydrogen energy will increase as the climate change policy is enforced, however, it will take long time for hydrogen energy to compete with fossil fuel. Therefore, it seems to be necessary to strengthen substantial policy supports for the production and use of hydrogen energy until the time hydrogen energy can compete with fossil fuel.
149 pages, 13 refs., 76 tabs., 5 Figs., Language: Korean |