Reducing environmental impacts through a smart design of microgrids: Life Cycle Assessment for AC and DC

Microgrids with integrated renewable energies have revealed promising potential to be a reliable, efficient, and clean key element for smart grid concepts. Further efficiency and reliability improvements might be achieved when the microgrid is operated with a direct current instead of an alternating current distribution. For a holistic assessment, the environmental impacts of this potential technology change should be advised. This study identifies and analyzes the differences of environmental impacts between ac and dc microgrids within office buildings to assist with smarter and more sustainable grid design in buildings. The differences in power electronics and distribution systems have been investigated on a micro-level in a comparative and scalable life cycle assessment and combined on a macro-level within a generic grid model. The analysis shows that the environmental impacts of power electronics can be reduced when utilizing a dc microgrid. The main driver for the differences in impacts has been identified as the energy supplied by the public grid. It can be inferred from the results that dc microgrids with integrated high-efficiency components have an ecological superiority compared to ac microgrids

Electric Vehicle Public Charging Infrastructure Planning Using Real-World Charging Data

The current increase of electric vehicles in Germany requires an adequately developed charging infrastructure. Large numbers of public and semi-public charging stations are necessary to ensure sufficient coverage. To make the installation worthwhile for the mostly private operators as well as public ones, a sufficient utilization is decisive. An essential factor for the degree of utilization is the placement of a charging station. Therefore, the initial site selection plays a critical role in the planning process. This paper proposes a charging station placement procedure based on real-world data on charging station utilization and places of common interest. In the first step, we correlate utilization rates of existing charging infrastructure with places of common interest such as restaurants, shops, bars and sports facilities. This allows us to estimate the untapped potential of unexploited areas across Germany in a second step. In the last step, we employ the resulting geographical extrapolation to derive two optimized expansion strategies based on the attractiveness of locations for electric vehicle charging

Electric Vehicle Public Charging Infrastructure Planning Using Real-World Charging Data

The current increase of electric vehicles in Germany requires an adequately developedcharging infrastructure. Large numbers of public and semi-public charging stations are necessary toensure sufficient coverage. To make the installation worthwhile for the mostly private operators aswell as public ones, a sufficient utilization is decisive. An essential factor for the degree of utilizationis the placement of a charging station. Therefore, the initial site selection plays a critical role in theplanning process. This paper proposes a charging station placement procedure based on real-worlddata on charging station utilization and places of common interest. In the first step, we correlateutilization rates of existing charging infrastructure with places of common interest such as restaurants,shops, bars and sports facilities. This allows us to estimate the untapped potential of unexploitedareas across Germany in a second step. In the last step, we employ the resulting geographicalextrapolation to derive two optimized expansion strategies based on the attractiveness of locationsfor electric vehicle charging

A scalable life cycle assessment of alternating and direct current microgrids in office buildings

Microgrids integrating local renewable energy sources at low-voltage level show promising potentials in realizing a reliable, efficient, and clean supply of electricity. Further improvements are expected when such a microgrid is operated on direct current (dc) instead of alternating current (ac) infrastructure for power distribution commonly in use today. Our study aims to systemically quantify the gap between environmental impacts of microgrids at building level using the case study of power distribution within office buildings. For this purpose, a scalable comparative life cycle assessment (LCA) is conducted based on a technical bottom-up analysis of differences between ac and dc microgrids. Particularly, our approach combines the assessment of required power electronic components on a micro-level with the macro-level requirements for daily operation derived from a generic grid model. The results indicate that the environmental impacts of employed power electronics are substantially reduced by operating a microgrid based on dc power distribution infrastructure. Our sensitivity analyses show that efficient dc microgrids particularly lead to savings in climate change impact emissions. In addition, our study shows that the scaling of power electronics as it is currently state of the art in LCAs leads to inaccurate results. Therefore, our developed method applies a more technical approach, which enables a detailed analysis of the environmental impacts of power electronic components at system level. Thus, it lays the foundation for an evaluation criterion for a comprehensive assessment of technological changes within the framework of energy policy objectives