Investigating the mechanism of interactions between carbon pricing policy and capacity mechanism

概要

（ 続紙 １ ）
京都大学

博士（エネルギー科学）

氏名

羅

依倫

Investigating the mechanism of interactions between carbon pricing policy
論文題目

and capacity mechanism
(炭素価格付け政策と容量メカニズムの相互作用の探究)

（論文内容の要旨）

This study explores the interaction between carbon pricing policy and capacity
mechanism in liberalized electricity markets. The thesis is comprised of five chapters,
each focusing on a specific aspect of the study.
Chapter 1 provides an overview of the research, including the research background,
aims, and significance. The existing literature related to the research problem is reviewed
from five aspects: carbon pricing policy, capacity mechanism, interaction among mixed
policies, and simulation-based policy design methods.
Chapter 2 proposes a conceptual framework for studying policy interactions, aimed
at exploring the interactions between carbon pricing policy and capacity mechanism in
liberalized electricity markets. Using the traditional System Dynamics model to simulate
the trajectory changes of power mix in order to verify the framework. The results show
that the proposed framework can be used for supporting quantitative analyze the
interaction between policies. It is found that there are potential conflicts between carbon
pricing policy and capacity mechanism in liberalized electricity markets.
Chapter 3 describes the development of an optimization-embedded hybrid System
Dynamics model. This is aimed at reducing the simulation bias of the traditional System
Dynamics method in the high variable renewable energy (VRE) penetration system, since
the traditional method is difficult to model the technical details of grid dispatching. By
comparing the changes in power capacity installation changes, electricity generation,
carbon emissions, and other indicators under different policy implementation scenarios, it
is found that the traditional model overestimates the emission reduction effect of carbon
pricing policy and the stability of the system. The bias of the traditional method increases
with the introduction of VRE. Thus, confirming the rationality and effectiveness of the
hybrid System Dynamics model in studying the interaction between carbon pricing
policy and capacity mechanism.
Chapter 4 follows the proposed framework to simulate the power mix trajectory
changes using the hybrid model, thereby investigating the interactions between the two
policies and their effects. Results demonstrate that the interaction between carbon pricing

policy and capacity mechanism is contingent on the specific policy design and intensity,
with conflicts or synergies varying across different perspectives. If policymakers
prioritize emission reduction, a high carbon floor price with flexible resources focus
capacity mechanism show synergies, especially under high VRE deployment.
Conversely, if economic benefits are the primary goal, policymakers may consider a
basic carbon floor price with a thermal power-focused capacity mechanism, regardless of
VRE deployment.
Chapter 5 summarizes the main conclusions and explains future work.
The contributions of the study are primarily:
•

a quantitative analysis framework for policy interaction mechanisms, thereby
allowing to study of the relationship between carbon pricing policies and capacity
mechanism in liberalized electricity markets.

•

an optimization-embedded hybrid System Dynamic model, improved the simulation
abilities of System Dynamics by adding technical details of grid dispatch.

Clarification of the interaction between carbon pricing policy and capacity
mechanism in liberalized electricity market, providing references for understanding
the trade-off in policy design of energy system transition.
Overall, this study provides valuable insights into the interaction between carbon
pricing policy and capacity mechanism in liberalized electricity markets. The findings of
this study can help policymakers make comprehensive decisions on energy policies and
provide a foundation for future research in this field.
•

（続紙 ２ ）

（論文審査の結果の要旨）

Liberalized electricity markets have emerged across the world, including in
Japan in recent years, with hopes that they will provide competition and
efficiently reduce prices for consumers. When conventional fossil fuels are used,
the demand-supply balance can be readily assured, but CO2 is emitted,
exacerbating global warming. Policies such as carbon taxes and feed-in-tariffs
are applied to such markets to reduce CO2 emissions and introduce renewable
energy. But variable renewable energy (VRE) such as solar photovoltaics and
wind power cannot be controlled, leading to problems with demand-supply
balance. Additionally, if the carbon price is too high, then fossil-fuel generators
will rapidly leave the market, leaving a gap in supply. To address the latter
issue, capacity prices are applied to maintain sufficient supply capacity. When
more than one of these policies is implemented, they may have complex
interactions, potentially leading to reduced effectiveness – for example, fossil
fuel power stations could be paid a capacity price but required to pay a carbon
price. Thus there is a need to develop quantitative models that can be used to
test the outcomes on the energy system when multiple policies are applied at
the same time.
This thesis developed three models of increasing complexity to address these
problems, using system dynamics and optimization techniques, and applied the
models to the case study of Hokkaido, Japan. The following three contributions
to knowledge were obtained:
1.
A framework for quantitative analysis of the interaction between
carbon policy and capacity mechanism was developed.
2.
A hybrid method that embedded optimization into system dynamics
model and allows the consideration of detailed technical factors with different
time scales in policy simulation was developed and showed that typical models
lead to overly-optimistic results, which can be mitigated with this model.
3.
The specific effects on power mix trajectories were identified,
considering the interaction between the two policies under 11 different
scenarios, showing that under high VRE scenarios the conflicts become larger,
and traditional models do not sufficiently show the difference. The
implementation of high carbon prices and high feed-in-premiums along with
capacity prices targeting flexible power plants (LNG) produces synergies
leading to lower emissions, but the integration of VRE reaches a limit and

cannot provide zero emissions unless further measures are taken. When there
is no discrimination between fossil fuel capacity, and when the carbon price is
lowered, the policies show conflicts, leading to lower efficiency and higher
emissions.
よって、本論文は博士（エネルギー科学）の学位論文として価値あるものと認める。ま
た、令和５年７月２８日実施した論文内容とそれに関連した試問の結果合格と認めた。

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