Contributions to web-based simulation software for sustainable energy systems

Motiviert durch den Bedarf an praxisorientierten Studien für die Energiewende befasst sich diese Dissertation in zehn Artikeln mit der Entwicklung, Evaluierung, Validieren, Anwendung und Abstraktion des multidimensionalen Entscheidungsunterstützungssystems NESSI. NESSI ist eine frei zugängliche, webbasierte Software zur Simulation von nachhaltigen Energiesystemen für Gebäude und Nachbarschaften. Mithilfe eines adaptierten Design Science Forschungsansatzes, wird NESSI in dieser Dissertation in fünf aufeinander folgenden Designzyklen speziell für Akteure in Entwicklungsländern weiterentwickelt. Für jeden Designzyklus wurden Anforderungen durch systematische Marktrecherchen, Literaturanalysen, Anwendertests und Experten- und Expertinneninterviews abgeleitet. Nach umfangreichen iterativen Programmierarbeiten wird jeder Designzyklus demonstriert, evaluiert und validiert, indem die Software in verschiedenen Kontexten in Entwicklungsländern eingesetzt wird. Weitere Methoden zur Verbesserung von NESSI waren Feedback von Gutachtern sowie Präsentationen auf nationalen und internationalen Veranstaltungen. Zur weiteren Demonstration von NESSI werden in zwei Artikeln umfangreiche Fallstudien in Thailand und Kolumbien beschrieben. Durch diese Entwicklungsarbeiten entstand ein zusätzlicher Artikel in Kooperation mit einem internationalen, interkontinentalen Projektteam, in dem die Weiterentwicklung des in NESSI integrierten Lastprofilgenerator RAMP dargelegt wird. In einem weiteren Artikel wird die Funktionsweise von NESSI vorgestellt, um dessen Vertrauenswürdigkeit und Transparenz zu fördern sowie globale Anwendungsmöglichkeiten zu verdeutlichen. Der letzte Artikel befasst sich mit entstehender Designtheorie. Ausgehend von NESSIs Entwicklungsprozess, werden sieben fundierte Designprinzipien für Entscheidungsunterstützungssystemen zur Unterstützung der gesellschaftlichen Nachhaltigkeitstransformation formuliert. Während des gesamten Entwicklungsprozesses hat sich gezeigt, dass das Entscheidungsunterstützungssystem NESSI die Energiewende bottom-up unterstützt, Stakeholder informiert und Menschen befähigt. Es werden jedoch auch einige Limitationen des Tools aufgrund von Simplifikationen aufgezeigt. Darüber hinaus werden die Herausforderungen bei der Entwicklung der Software erläutert, insbesondere in Bezug auf die Definition der Stakeholder, Forschung aus der Ferne, die Komplexität und Vertrauenswürdigkeit des Tools sowie die Bedeutung von Stakeholder-Netzwerken. Akteure und Forschende werden eingeladen, NESSI weiter zu verbessern, den Ansatz zu hinterfragen und gemeinsam ein verfeinertes Modell zu entwickeln, um die Energiewende bottom-up zu fördern und die Entwicklung gesellschaftlicher Nachhaltigkeit zu unterstützen.Motivated by the calls for more solution-oriented studies that contribute to the energy transition, this dissertation comprises of ten articles describing the development, evaluation, validation, application, and abstraction of the multi-criteria decision support system NESSI. NESSI is an openaccess, web-based software simulating energy systems for buildings and neighborhoods. Using an adapted design science research approach, NESSI is further developed in five consecutive design cycles specifically for actors in developing countries. For each design cycle, requirements were derived through systematic market research, literature analyses, user tests, and expert interviews. After extensive iterative programming works, each design cycle is demonstrated, evaluated, and validated by applying the software to suitable contexts in developing countries. Further methods to improve and validate NESSI included reviewer feedback as well as presentations at national and international events. Two articles describe extensive case studies situated in Thailand and Colombia to further demonstrate NESSI. This work led to a joint article, co-authored with an international project team, which presents the load profile generator RAMP and its integration into NESSI. Moreover, the functionality of the tool is introduced in a separate article to serve as a manual, to support transparency, trust, and credibility as well as to highlight the tool’s global applicability. In the last article, nascent design theory is derived by formulating seven grounded design principles with multiple design features for the wider application of bottom-up societal sustainability transformation. Throughout this development process, it was proven that the decision support system NESSI supports bottom-up energy transition, educates stakeholders, and empowers people. Nevertheless, several limitations regarding the tool’s restrictiveness are highlighted. Challenges during software development are elaborated on, especially in terms of the stakeholder definition, the remote research approach, the tool’s complexity and credibility as well as importance of stakeholder networks. Stakeholders and researchers are invited to further improve NESSI, challenge th

Fostering Energy Resilience in the Rural Thai Power System—A Case Study in Nakhon Phanom

With rising electricity demand, heavy reliance on imports, and recent economic downturns due to the negative impact of the COVID-19 pandemic, supply chain bottlenecks, and the Russian invasion of Ukraine, Thailand is suffering severely from energy resilience risks. The government has therefore set a goal of decentralizing energy production through small-scale distributed renewable energy systems. To support their design and the planning process, we simulate multiple scenarios with wind turbines, photovoltaic systems, and battery storage for a model community in rural Nakhon Phanom, Thailand. Using the software NESSI4D, we evaluate and discuss their impact on energy resilience by considering environmental sustainability, economic attractiveness, and independence from the central power grid. To fill the gap of missing data on energy demand, we synthesize high-resolution load profiles from the Thailand Vietnam Socio-Economic Panel. We conclude that distributed photovoltaic systems with additional battery storage are only suitable to promote energy resilience if the government provides appropriate financial incentives. Considering temporal variations and local conditions, as well as a participatory decision-making process, are crucial for the long-term success of energy projects. Our advice to decision-makers is to design policies and regulatory support that are aligned with the preferences and needs of target communities

Fostering Energy Resilience in the Rural Thai Power System—A Case Study in Nakhon Phanom

With rising electricity demand, heavy reliance on imports, and recent economic downturns due to the negative impact of the COVID-19 pandemic, supply chain bottlenecks, and the Russian invasion of Ukraine, Thailand is suffering severely from energy resilience risks. The government has therefore set a goal of decentralizing energy production through small-scale distributed renewable energy systems. To support their design and the planning process, we simulate multiple scenarios with wind turbines, photovoltaic systems, and battery storage for a model community in rural Nakhon Phanom, Thailand. Using the software NESSI4D, we evaluate and discuss their impact on energy resilience by considering environmental sustainability, economic attractiveness, and independence from the central power grid. To fill the gap of missing data on energy demand, we synthesize high-resolution load profiles from the Thailand Vietnam Socio-Economic Panel. We conclude that distributed photovoltaic systems with additional battery storage are only suitable to promote energy resilience if the government provides appropriate financial incentives. Considering temporal variations and local conditions, as well as a participatory decision-making process, are crucial for the long-term success of energy projects. Our advice to decision-makers is to design policies and regulatory support that are aligned with the preferences and needs of target communities

Fostering Energy Resilience in the Rural Thai Power System—A Case Study in Nakhon Phanom

With rising electricity demand, heavy reliance on imports, and recent economic downturns due to the negative impact of the COVID-19 pandemic, supply chain bottlenecks, and the Russian invasion of Ukraine, Thailand is suffering severely from energy resilience risks. The government has therefore set a goal of decentralizing energy production through small-scale distributed renewable energy systems. To support their design and the planning process, we simulate multiple scenarios with wind turbines, photovoltaic systems, and battery storage for a model community in rural Nakhon Phanom, Thailand. Using the software NESSI4D, we evaluate and discuss their impact on energy resilience by considering environmental sustainability, economic attractiveness, and independence from the central power grid. To fill the gap of missing data on energy demand, we synthesize high-resolution load profiles from the Thailand Vietnam Socio-Economic Panel. We conclude that distributed photovoltaic systems with additional battery storage are only suitable to promote energy resilience if the government provides appropriate financial incentives. Considering temporal variations and local conditions, as well as a participatory decision-making process, are crucial for the long-term success of energy projects. Our advice to decision-makers is to design policies and regulatory support that are aligned with the preferences and needs of target communities

Threefold Sustainable Neighborhood Energy Systems: Depicting Social Criteria in Decision Support Systems

Despite the consensus that considering social factors is as important as economic and environmental dimensions for long-term successful, sustainable energy development projects, there is a lack of quantifiable assessments in multi-energy simulation decision support systems. Therefore, we applied a design science research approach to develop an energy system simulator that includes all three dimensions of sustainability. Based on a rigorous literature review and expert interviews, we establish a framework for assessing social sustainability. We then implement the derived criteria and indicators in the open-access software NESSI and validate it in an applicability check for a Madagasi neighborhood. With our framework, we aim to provide guidance to researchers and stakeholders on incorporating the social sustainability dimension into their approaches, tools, and decision-making process. The user-friendly, web-based simulation software enables various stakeholders to explore the interrelationships of threefold sustainability in specific energy systems

Health-status outcomes with invasive or conservative care in coronary disease

BACKGROUND In the ISCHEMIA trial, an invasive strategy with angiographic assessment and revascularization did not reduce clinical events among patients with stable ischemic heart disease and moderate or severe ischemia. A secondary objective of the trial was to assess angina-related health status among these patients. METHODS We assessed angina-related symptoms, function, and quality of life with the Seattle Angina Questionnaire (SAQ) at randomization, at months 1.5, 3, and 6, and every 6 months thereafter in participants who had been randomly assigned to an invasive treatment strategy (2295 participants) or a conservative strategy (2322). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate differences between the treatment groups. The primary outcome of this health-status analysis was the SAQ summary score (scores range from 0 to 100, with higher scores indicating better health status). All analyses were performed in the overall population and according to baseline angina frequency. RESULTS At baseline, 35% of patients reported having no angina in the previous month. SAQ summary scores increased in both treatment groups, with increases at 3, 12, and 36 months that were 4.1 points (95% credible interval, 3.2 to 5.0), 4.2 points (95% credible interval, 3.3 to 5.1), and 2.9 points (95% credible interval, 2.2 to 3.7) higher with the invasive strategy than with the conservative strategy. Differences were larger among participants who had more frequent angina at baseline (8.5 vs. 0.1 points at 3 months and 5.3 vs. 1.2 points at 36 months among participants with daily or weekly angina as compared with no angina). CONCLUSIONS In the overall trial population with moderate or severe ischemia, which included 35% of participants without angina at baseline, patients randomly assigned to the invasive strategy had greater improvement in angina-related health status than those assigned to the conservative strategy. The modest mean differences favoring the invasive strategy in the overall group reflected minimal differences among asymptomatic patients and larger differences among patients who had had angina at baseline

Initial invasive or conservative strategy for stable coronary disease

BACKGROUND Among patients with stable coronary disease and moderate or severe ischemia, whether clinical outcomes are better in those who receive an invasive intervention plus medical therapy than in those who receive medical therapy alone is uncertain. METHODS We randomly assigned 5179 patients with moderate or severe ischemia to an initial invasive strategy (angiography and revascularization when feasible) and medical therapy or to an initial conservative strategy of medical therapy alone and angiography if medical therapy failed. The primary outcome was a composite of death from cardiovascular causes, myocardial infarction, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest. A key secondary outcome was death from cardiovascular causes or myocardial infarction. RESULTS Over a median of 3.2 years, 318 primary outcome events occurred in the invasive-strategy group and 352 occurred in the conservative-strategy group. At 6 months, the cumulative event rate was 5.3% in the invasive-strategy group and 3.4% in the conservative-strategy group (difference, 1.9 percentage points; 95% confidence interval [CI], 0.8 to 3.0); at 5 years, the cumulative event rate was 16.4% and 18.2%, respectively (difference, 121.8 percentage points; 95% CI, 124.7 to 1.0). Results were similar with respect to the key secondary outcome. The incidence of the primary outcome was sensitive to the definition of myocardial infarction; a secondary analysis yielded more procedural myocardial infarctions of uncertain clinical importance. There were 145 deaths in the invasive-strategy group and 144 deaths in the conservative-strategy group (hazard ratio, 1.05; 95% CI, 0.83 to 1.32). CONCLUSIONS Among patients with stable coronary disease and moderate or severe ischemia, we did not find evidence that an initial invasive strategy, as compared with an initial conservative strategy, reduced the risk of ischemic cardiovascular events or death from any cause over a median of 3.2 years. The trial findings were sensitive to the definition of myocardial infarction that was used