Local Decentralized Energy Systems for Resilient Cities

Microgrids could make urban infrastructures more resilient to power outages due to climate disasters or cyberattacks. A study examines how cities could make the transformation to sustainable supply fair.

22.07.2024 – A global IT outage had partially paralyzed international air and rail traffic last Friday, and some banks and media companies were also affected. This has once again clearly demonstrated the dependence on a networked and functioning infrastructure. Urban infrastructures are also increasingly exposed to major risks, e.g. large-scale power outages after a serious cyber attack or extreme weather events caused by climate change, most recently e.g. the massive flooding of large parts of southern Germany.

But how can urban infrastructures be made more resilient and how can risks for the population be reduced?

The question of how cities and municipalities can make the supply and security of the population more resilient to such crises is coming into focus on so-called microgrids, i.e. local decentralized energy systems. Researchers of Karlsruhe Institute of Technology (KIT) have taken up the topic and present design criteria for such microgrids in the current issue of the journal Nature Sustainability, which, in addition to technical factors, take into account fair treatment of different social groups.

Planning basis for urban planners: Integrating different aspects

Decentralized systems for the generation, storage and distribution of energy, for example with networked photovoltaic systems and combined heat and power plants, could make large-scale power outages throughout the city less likely and ensure the function of critical infrastructures of general interest, according to the study.

A group of German and U.S. researchers headed by Dr. Sadeeb Simon Ottenburger, Head of Department at the Institute of Thermal Energy Technology and Safety (ITES) of KIT, has developed a model for a spatial planning concept of microgrids. The study offers urban planners a template for a planning process that integrates various aspects – including socio-economic factors and questions of social participation in the planning process. Employees of ITES, the Institute for Technology Assessment and Systems Analysis (ITAS) of KIT, and in the United States of the Energy Production and Infrastructure Center (EPIC) of the University of North Carolina and the National Renewable Energy Laboratory (NREL) in Colorado were involved.

Energy Gerrymandering: Who has access to the energy supply?

"A special feature of our approach is that we do not consider technical parameters or cost issues in isolation, but deal with the question of what role the design of microgrids plays in terms of a fair distribution of supply," explains Ottenburger. "Think of the city as a puzzle. How the puzzle pieces are cut can vary. The demarcation of energy grids is the result of conscious decisions and has an impact on the population. In the event of a crisis, it makes a difference how health, safety and food supplies are distributed within individual microgrids, but also throughout the entire urban area."

Planning leeway

With the term "degrees of freedom", the study emphasises the importance of planning leeway. To point out potentially negative consequences of divisions that do not take into account social justice issues, the study authors used the term "energy gerrymandering", based on political gerrymandering, known from the United States, when drawing electoral districts to the advantage of certain groups. The definition of microgrid districts can therefore lead to an unfair distribution of resources and advantages, the researchers explain. Strong and wealthy groups could be preferred, while socially weaker and vulnerable groups could be disadvantaged. "Resilience also includes defining how access is designed for different groups of the population," says Ottenburger.

Evaluation of well-being as a relevant metric

The study focuses on the connection between the different vulnerabilities of social groups and equitable access to energy and supply. To this end, the researchers have developed metrics using existing vulnerability indices that describe the well-being of the population as a measure and show how energy outages affect socially and economically sensitive groups in particular: the sick, families with children, the elderly and low-income earners.

Data from case study after hurricane

The data basis for this was a comprehensive case study after power outages during Hurricane Florence in September 2018 in New Hanover County, North Carolina, the research team reports. These were contributed by the project partners in the United States. The data enabled an analysis of critical infrastructure, its vulnerability in connection with the geographical distribution of socially disadvantaged households and their access to basic services. The project team developed a universal design that makes it possible for each city to comprehensively assess urban resilience and generate proposals for a design of microgrids that will take into account technical and social issues.

Ensuring fair participation

For a fair distribution and accessibility of critical services such as health and safety structures, a city should build not just one, but several microgrids, the study authors recommend. With regard to the boundaries of the supply networks, city administrations should actively involve institutions in the areas of health care and security, representatives of different social groups, educational institutions and social services in the planning and decision-making processes – in order to take into account the needs of all social groups as fairly as possible.

"The search for optimized microgrid layouts is highly complex and requires new algorithms to develop viable models from the existing data," says Ottenburger. The decisive factor here would be that resilient solutions are not necessarily a question of more investment – but above all of clever planning. "We should make sure that all groups have a voice and can participate in these processes."

source : Strategies in the Climate Crisis: Microgrids for Resilient Cities - energiezukunft