Yasumasa Fujii

Inter-generational and spatial equity issues of carbon accounts

We analyze the different regional and generational contributions to increases of CO2 concentrations resulting from fossil-fuel use since the onset of the industrial revolution. Equitable future per capita emission allowances under a range of concentration stabilization scenarios (additional 140, 280, and 420 ppm over pre-industrial levels) by the year 2100 are outlined. The intra- and inter-generational equity criterion adopted considers that each human being is allowed an equal emission right per year, independent of time or place lived. A distinguishing characteristic of the analysis is the integration of emissions and population over time. Quantifications of historical contributions to concentration increases and future emission scenarios on a per capita basis are broken down into nine world regions.

Role of CO2 sequestration by country for global warming mitigation after 2013

Publisher Summary This chapter evaluates CO2 sequestration technologies in parallel with other mitigation technologies and also in consideration of their regional differences. Five kinds of CO 2 sequestration technologies are modeled: enhanced oil recovery, depleted gas well sequestration, enhanced coal-bed methane, aquifer sequestration, and ocean sequestration. The divided regions are interlinked through transportations of CO 2 and various kinds of energies. The model is an intertemporal optimization type; the objective function is the total cost of energy systems plus CO 2 sequestration between 2000 and 2050. Energy supply systems and CO 2 capture and sequestration technologies are represented in the bottom-up fashion in order to evaluate technological strategies of CO 2 emission mitigation technologies. CO 2 sequestration potentials of the 77 divided regions were estimated based on several geographical information systems (GIS) data. The model analysis results show that CO 2 sequestration accounts for a large part of the total CO 2 emission reduction; the amounts of the cumulative world CO 2 sequestration between 2000 and 2050 are about 45 GtC and 65 GtC with and without emission trading, respectively, and that the cost effective strategies differ by region. In the emission trading case, all the four types of underground CO 2 sequestration technologies are utilized for US; the sequestration into ocean and aquifer are utilized for Japan. CO 2 sequestration technologies would decrease the world marginal cost of CO 2 reduction in 2050 by about 59

Analysis of the optimal configuration of energy transportation infrastructure in Asia with a linear programming energy system model

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Basic analysis of the pricing processes in modeled electricity markets with multi-agent simulation

It has become important to address the question of which energy related infrastructure, such as transcontinental natural gas pipelines, should be constructed in Asia. In addition, one needs to ask how energy demand should be satisfied securely and economically, as well as environmentally benignly, over the next decades. This study investigates the possible future configuration of energy and CO2-related infrastructure in Asia and Eurasia, using a large-scale energy system model, which minimises inter-temporally the sum of the discounted total energy system costs until the year 2050. The model explicitly involves intra-regional transportation networks of fuels and recovered CO2 among approximately 100 nodes in Asia and Eurasia. The preliminary results indicate that long distance natural gas pipelines will be developed extensively in Asia and Eurasia, and that issuing carbon taxes of a few hundred dollars per ton of carbon enhance substantially the consumption of natural gas in electricity generation sectors, as a substitute fuel for coal. Such carbon taxes will make CO2 sequestration economically viable while increasing the cumulative amount of CO2 sequestration up to 15 gigatons (Gt) of CO2.

Prospects for interregional energy transportation in a CO 2 -constrained world

Many electric utilities world-wide have been forced to change their ways of doing business, from vertically integrated systems to open market ones. In Japan, we are facing urgent issues about how to design the structures of power market. In order to cope with the issue, many studies have been made with market models. However, there are many kinds of modeling methods, and no particular method has been established so far. Each has drawbacks and advantages about validity and versatility. This paper presents the method to use a multi-agent model, which learns a bidding strategy autonomously through trial-and-error search action, as useful tools of numerical analysis of the price formation process of an electric power market. The model enables us to analyze more general electricity markets, which have several different types of power plants with unit commitment costs, seasonal and hourly demand fluctuation, real-time regulation market and operating reserve market. This model figures out the issues that may be appeared when we will design markets and the way of designing operating reserve market.

Long-Term Energy and Environmental Strategies

In this paper, a regionally disaggregated global energy model treating energy and CO2 transportation in detail is used to examine a cost-effective pattern for their interregional transportation over the 21st century under the CO2 stabilization target of 550ppm. Also, we assess future perspectives for the hydrogen economy in such a scenario. The results show that as major petroleum and gas supplies shift to unconventional resources along the second half of this century due to resource depletion, the Middle East loses its importance as a petroleum and gas exporter and the global patterns of their transportation change significantly. We then show that while hydrogen’s competitiveness decreases due to the detailed treatment of energy and CO2 transportation, biomass-derived Fischer-Tropsch (FT) fuels become attractive because their production facilitates a wide diffusion of CO2-neutral energy carriers by considerably reducing the transportation cost. FT fuels are produced in regions rich in forest resources and then transported on a large scale by tanker. By contrast, hydrogen is produced mainly at the center of its consumption regions using domestic feedstock, and its interregional delivery, which is done only by pipeline, plays a marginal role due to its high transportation cost. It is confirmed that such a hydrogen supply structure offers energy security benefits. Finally, we show that the regional distribution of CO2 storage capacity is a major determinant of the pattern of hydrogen transportation around 2100, because all the CO2 generated from hydrogen production is required to be captured for sequestration in that period and because interregional CO2 transportation is hardly chosen for economic reasons.

Analysis for large-scale integration of PV system in Japan with a high time-resolution optimal power generation mix model

This chapter investigates long-term energy and environmental strategies, employing a regionally disaggregated Dynamic New Earth 21 model (called DNE21) which allows us to derive a normative future image of energy systems through the comprehensive incorporation of forecasted future technologies. This integrated energy system model, explicitly considering the availability of advanced nuclear technologies such as nuclear fuel cycle and fast breeder reactors which can improve the usage efficiency of natural uranium resources, employs computational tools to evaluate the optimal global energy mix compatible with low atmospheric CO2 concentrations. Simulation results in the model indicate that massive CO2 mitigation targets can be achieved with the large-scale deployment of innovative technology, highlighting roles for nuclear, renewables, efficient use of fossil fuel, and carbon capture and storage (CCS). The results support the simultaneous pursuit of multiple technologies, rather than focusing merely on realistic technological options based on current perceptions. However, the validity about the expected role of nuclear energy for the future should be critically evaluated in the new technical and political contexts that exist after the Fukushima nuclear accident.

Decision analysis under uncertain CO 2 regulation policies with a global energy model and its implication for power system planning

This paper assesses the possible integration of a massive PV resource into the power generation mix in Japan using a high time-resolution optimal power generation mix model. The feature of the model allows us to explicitly consider actual PV and wind output variability in 10-minute resolution on 365 days. Simulation results reveal that both the suppression control of PV output and rechargeable battery installation show a significant increase when PV installs at more than the similar scale of the peak demand or PV fraction in total power generation exceeds the level of around 20 percent. The calculated results imply as well that a large-scale integration of PV potentially decreases the usage ratio of LNG combined cycle (LNGCC) in specific seasons, which suggests the challenge for utility companies to assure LNGCC serving as a profitable ramp generator for treating the PV variability.

Evaluation of Optimal Power Generation Mix Considering Nuclear Power Plants’ Shut-Down Risk

Global warming caused by the increase of atmospheric CO2 concentration is regarded as a serious environmental issue. Due to uncertainty relating to the mechanisms of the terrestrial carbon cycle and climate system, solution of the problem is considered to be extremely complicated. In such a context, to conduct a decision analysis under uncertain CO2 concentration control policies, we have developed a global energy model which minimises the expected value of discounted total energy system costs up to the year 2055. In this work, we analyse an optimal future global energy system, particularly focusing on the Japanese electric power sector and present insight into an optimal strategy for energy system development under uncertain CO2 regulation policies.

Assessment of technological options to reduce CO2 emissions with a global energy network model

After Fukushima nuclear power plant accident, resilience engineering has emerged as a new paradigm of risk management, and the design of resilient energy system is getting more and more important. Energy model analysis based on mathematical programming contributes to discussing how to implement resilience into energy system by identifying quantitative suggestions. In this paper, as an example of such analysis, the authors try to derive possible appropriate measures to enhance electricity supply system resilience to successive nuclear power plants’ shut-down risk. The model developed in this paper is a dynamic power generation planning model, which considers nuclear power plants’ shut-down risk stochastically and identifies resilient capacity expansion in Japan from 2012 to 2030 under the uncertainty of the risk from a quantitative perspective. This resilient capacity expansion includes the necessity of alternative power resources and demand response compensating for supply capacity loss due to nuclear power plants’ shut-down, considering economic constraints. Simulation results successfully show the need for these measures in the capacity expansion. Importantly, the suggestion is not like a future prediction but a normative image of the system through the comprehensive incorporation of forecasted future parameters and scenarios. The more detailed the parameters and the scenarios are, the better image can be obtained. Learning from past accidents and updating our scientific knowledge base will detail the parameters and the scenarios and make energy model analysis very effective. It will tell us how to make resilient energy system.