Example use cases

In the following, we provide a non-exhaustive list of example use cases for ZEN-garden. The presented use cases are past applications of ZEN-garden, and are meant to illustrate the flexibility of the framework.

European energy crisis

The Russian invasion of Ukraine in 2022 and the subsequent disruption of natural gas supply to Europe led to an energy crisis in Europe, with high energy prices and supply shortages.

In this study, ZEN-garden was used to analyze the impact of collaborative and selfish mitigation strategies to tackle the energy crisis. The operation of the European electricity, heating, and gas system was optimized for 28 European countries to minimize the total system costs and demand reductions.

We found that (1) selfish behavior of Central European countries exacerbates the energy scarcity for many Southeastern European countries; (2) proactive collaborative energy savings, together with a mild winter, can fully relieve the stress of the gas shortage; (3) diversification of gas imports leads to bottlenecks in the gas network, especially in Southeastern Europe; and (4) electricity generation is mostly shifted to coal-based power plants, causing higher carbon emissions.

Myopic foresight in the European energy transition

The long-term climate goals are often met by short-term - or myopic - decision-making, which can lead to suboptimal outcomes.

In this study, ZEN-garden was used to analyze the impact of myopic foresight on the European energy transition. The case study setup was similar to the one in the previous use case, but focusing on the capacity expansion of the European energy system. The technology expansion is constrained, i.e., the maximum capacity additions in each year are determined by the existing capacities.

We found through hindcasting that in the past, European emissions followed a myopic trajectory. In the future, myopic foresight and constrained technology expansion together may lead to carbon overshoot. Carbon prices can only effectively internalize long-term climate goals if they account for constrained technology deployment, increasing to around 400 EUR/tCO2 in 2050.

Technology optimism in carbon management technologies

Carbon management technologies are often considered a silver bullet for achieving climate goals. They are sought to rectify the mistakes of the past by removing carbon emissions from the atmosphere or point sources.

In this study, ZEN-garden was used to analyze the impact of unwarranted optimism in carbon management technologies on the European energy transition. To this end, the previous case study was extended to include many industrial and transport sectors. The technology optimism is modeled as a rolling horizon optimization under foresight error.

Optimism slows the required emission reduction in transport and heating by 30% and overshoots the remaining carbon budget by 50% in 2050.