| 摘要 | 1. Background and Research Objectives
Up to date, a large number of researches have been conducted on a hydrogen economy, none of which, however, seriously addresses the costs anticipated in implementing a hydrogen economy. In particular, the way in which hydrogen is produced, namely, feed-stocks and technologies for producing hydrogen is undeniably critical issue in determining whether the future energy system based on hydrogen is sustainable or not. If hydrogen production relies solely on fossil fuels such as natural gas and coal, it would perpetuate the age-old fossil energy system. The GEN-IV reactor under development for hydrogen production is regarded as a strategy to revive the nuclear industry which is recently undergoing a recession.
Hydrogen economy, if it is to be sustainable, should rely on renewable energy sources for hydrogen production, which is easier said than done. Renewable energy sources, except for a few, are costlier than the traditional energy sources, ranging from 20-30% to a factor of 10. This situation is expected to be improved in the near future. Within the next 20 to 30 years, except for wind, biomass, geothermal, and small hydro, hydrogen production based on photocatalytic hydrolysis and photo-electrolysis of biomass which currently remain at an early developmental stage, would not allow for any speculation of a large up-take without a technological break- through. In this context, our best bet is to produce hydrogen by an optimal mix among fossil fuels, nuclear power, and renewable energies.
With this in mind, and taking the report, "A National Vision of Hydrogen Economy and Action Plan" as a starting point, this study focuses firstly on estimating hydrogen requirements based on foecasting the demand for fuel cells in each energy sector. Secondly, it tries to find an optimal mix of fuel sources and technologies for hydrogen production, using Analytic Hierarchy Process (AHP). Lastly, this study suggests for systemic approach in a cost-effective implementation of hydrogen economy.
2. Major Findings
Major findings of this study are as follows:
Firstly, target markets for fuel cells in the industrial, residential, and commercial sectors are 6,848 thousand TOE (20.7%), 2,179 thousand TOE (20.7%), and 5,840 thousand TOE (20.7%), respectively. Fu�� cell vehicles will be introduced from 2015 and replace 5% of the total vehicles on the road by 2031 with a typical energy efficiency of 200% compared to the existing conventional vehicles.
Secondly, a mix of energy sources for hydrogen production was sought by applying analytic hierarchy process (AHP) methodology, based on a questionnaire twice executed for experts. The resulting mix is 29.5% for renewable energies, 23.6% for nuclear, 18.5% for natural gas, 12.6% for surplus electricity, 8.6% for byproduct gas, 7.1% for coal gasification. The optimal mix of energy sources for hydrogen production finalized in consideration of other factors such as resources potential of energy sources and socio-economic aspects, is 52.1% for renewable energies, 32.7% for natural gas, 12.6% for coal, 2.6% for byproduct gas, excluding nuclear and surplus electricity for reference case.
Thirdly, energy replacement by using hydrogen in the transportation sector was estimated to be 24,040 thousand TOE (51%) which accounts for 12,020 thousand TOE in terms of hydrogen energy. Fuel cell's share of energy market in the industrial, residential, and commercial sectors will be 73.2%, 36.8%, 65.6%, respectively in 2040. Hydrogen requirement in the transportation, industrial, residential/commercial sectors in 2040 for reference case will be 45.6%, 28.0%, 26.4%, respectively.
Fourthly, energy mix in the final energy consumption will be different by introducing hydrogen. Reduction in the oil consumption amounts to 16.5% against that in the BaU case, followed by 13.3% for electricity and 4.1% for heat with an average of 11.4%.
Fifthly, hydrogen's share in the final energy consumption in 2040 will be 8.7% for reference case, 11.5% for high oil price case, and 5.5% for low oil price case.
Lastly, the primary energy mix as a result of hydrogen introduction in 2040 will be 27.6% for oil, 23.4% for coal, 16,4% for LNG, 20.1% for nuclear, and 12.1% for renewable energies. This outcome implies that reduction in oil consumption is 17.3% vs that in the BaU case, 9.6% for natural gas, 4.9% up for coal, but increase in renewable energies amounts to 77.7% vs that in the BaU case. Consequently, CO2 emissions will be reduced by 20,437 thousand TC in 2040.
3. Suggestions for Further Studies
This study is to seek an optimal mix of feed-stocks in hydrogen production as a part of pathway towards a hydrogen economy. However, a couple of essential factors were not reflected in building a cost-effective infrastructure of hydrogen supply. Neither positive nor negative aspect of hydrogen economy was not discussed in a fair manner, resulting in a limited approach to a well-balanced strategies to realize a hydrogen economy.
In addition, non-technological and non-economical factors are not fully reflected in deriving an optimal mix of energy sources and technologies to produce hydrogen. Based on a survey conducted for the public in general, socio-political and cultural aspects of technology and energy sources should be analyzed and reflected in deriving an optimal mix.
In order to fully understand a socio-economic as well as political systems, a holistic and systemic approach is needed to identify issues and reach a cost-effective solution to them. Building a hydrogen supply infrastructure calls for a logistic approach from hydrogen production, through delivery and storage, to the end-users. This study couldn't provide any of directions and a list of what and how to do in this regards.
Lastly, identification of issues, agenda, and detailed action plan such as implementation organization, basic plan, codes and standards, safety etc. must be addressed. This issue will be approached with detailed discussion and analysis in the national project, "Institutional Arrangements for a Cost-Effective Implementation of a Hydrogen Economy" which will be underway the coming year. |
