Decentralization in energy systems - Low-carbon technologies and sector coupling on the household, community and city scales
Doctoral thesis, 2021

The number of installations of distributed energy technologies, such as solar photovoltaic (PV) and battery systems, has increased dramatically in recent decades. The required transition towards a decarbonized energy system entails electrification of the different sectors. Both these developments provide new opportunities for energy autonomy and sector coupling in decentralized systems, and allow local actors to contribute to reducing their climate impact.

The aim of this thesis is to study the utilization of local energy technologies and the potential for system flexibility in three decentralized energy systems: prosumer households, prosumer communities, and city energy systems. In addition, the thesis investigates the interactions of decentralized systems with the surrounding regional energy system.

In this work, four techno-economic energy system optimization models are used. In the first model, PV-battery systems in prosumer households are analyzed within the North European electricity system dispatch. In the second model, they are examined as part of prosumer communities. In the third, city-scale model the investment and dispatch in the electricity and district heating sectors are optimized, while considering flexible and inflexible charging of electric cars and buses. The fourth model combines the city and regional scales, to study the operation, design and interaction of both systems, while considering different connection capacities for electricity exchange between the systems.

The results show that the economic incentives for electricity self-consumption in prosumer households promote a way of utilizing household battery systems that is not in line with the least‑cost dispatch of the electricity system. Consequently, prosumer households are, within the current tariff structure, unlikely to provide flexibility that would assist the balancing of intermittency in the regional electricity system. In prosumer communities, where prosumer households have the possibility to share electricity, a financial benefit accrues to the participating households primarily when there is a reduced connection capacity for electricity exchange to the energy provider.

For city energy systems, it is shown that power-to-heat technologies in combination with thermal storage systems and flexibility with regards to the charging of battery electric vehicles facilitate the uptake of local solar PV. The city electric car fleet provides the potential to postpone up to 85% of the demand for charging, which leads to more than twice the share of solar PV in the electricity mix for charging, as compared with inflexible charging. A 50% connection capacity between the city-scale and regional-scale energy systems implies only 3% higher costs for the installation and operation of energy technologies on both scales, as compared with a system that has 100% connection capacity.

This thesis outlines the potential for increased decentralization of the energy supply and highlights the need for strategies to integrate decentralized and centralized energy systems.

Smart city

Sector coupling

Energy systems modeling

Decentralization

Electric vehicles

Prosumers

Energy system flexibility

Energy community

Online
Opponent: Professor Russell McKenna, School of Engineering, University of Aberdeen, Aberdeen, United Kingdom

Author

Verena Heinisch

Chalmers, Space, Earth and Environment, Energy Technology

Interconnection of the electricity and heating sectors to support the energy transition in cities

International Journal of Sustainable Energy Planning and Management,; Vol. 24(2019)p. 57-66

Journal article

Heinisch, V., Göransson, L., Odenberger, M., Johnsson, F. The impact of limited electricity connection capacity on energy transitions in cities

Actions towards the energy transition and a reduction of greenhouse gas emissions are being taken in various parts of the energy system. The rapid decline in costs for solar photovoltaic (PV) and battery systems, for instance, has enabled households to invest in small-scale energy technologies and to produce and use renewable energy on their properties. In addition, stringent energy targets for cities are being formulated to ensure sustainable expansion of urban areas, while simultaneously reducing their negative impact on climate. Both these examples show the trends towards increased decentralization of the energy supply and the planning of energy systems. As a consequence of decentralization, many generation and storage units and a variety of actors will have to be coordinated in future energy systems, to a greater extent than in the traditional, predominately centralized system.

In this thesis, decentralized energy systems are studied with the help of techno-economic optimization models. These models allow to study the uses and interactions of energy technologies and provide inputs to energy planning on, for instance, system designs that meet emission reduction targets and supply energy demands.

This work shows the impact that a high number of households with PV-battery installations, so-called ‘prosumer households’, have on the electricity system. It also studies the potential benefits to prosumers of sharing electricity between households. With respect to city energy systems, the thesis investigates how different types of energy storage, the use of electricity in the district heating system, and smart charging strategies for electric cars and buses can facilitate the uptake of local renewable electricity generated from solar PV. Finally, the work compares the designs and costs of energy systems in which cities rely primarily on electricity imports from the surrounding electricity system to a situation with increased local energy generation within the cities.

New networks of power: on the emergence, diffusion and impact of alternative electricity system architectures

Swedish Energy Agency, 2015-01-01 -- 2018-12-31.

Subject Categories

Energy Engineering

Energy Systems

Areas of Advance

Energy

ISBN

978-91-7905-478-6

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4945

Publisher

Chalmers University of Technology

Online

Online

Opponent: Professor Russell McKenna, School of Engineering, University of Aberdeen, Aberdeen, United Kingdom

More information

Latest update

4/16/2021