Jan Frederick Unnewehr

2020

• Unnewehr J
  Tracking CO2 emissions from power generation in high spatial and temporal resolution – Case study for the German electricity system
  2020 Energy Informatics, Band: 3
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  Kurzfassung

  Until today it is not possible to allocate the CO2 emissions in the German electricity system to a specific region and its corresponding electricity demand that caused them. This paper presents a new energy system model and uses established methods for answering this question. A detailed bottom-up model of the German electricity system is built to represent a highly spatial and temporal representation of the Germany electricity system in 2019. In combination with a customized input-output analysis, the individual emissions from the producer to the caused consumer can be traced. The analysis demonstrates the importance of considering spatial and temporal effects as well as electricity exchanges between regions in estimating emissions footprints.
• Unnewehr J F, Waldl H-P, Pahlke T, Weidlich A
  Reducing Operational Costs of Offshore HVDC Energy Export Systems Through Optimized Maintenance
  2020 Energies, Band: 13, Nummer: 1146, Seiten: 1 - 20
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  Kurzfassung

  For the grid connection of offshore wind farms today, in many cases a high-voltage direct current (HVDC) connection to the shore is implemented. The scheduled maintenance of the offshore and onshore HVDC stations makes up a significant part of the operational costs of the connected wind farms. The main factor for the maintenance cost is the lost income from the missing energy yield (indirect maintenance costs). In this study, we show an in-depth analysis of the used components, maintenance cycles, maintenance work for the on- and offshore station, and the risks assigned in prolonging the maintenance cycle of the modular multilevel converter (MMC). In addition, we investigate the potential to shift the start date of the maintenance work, based on a forecast of the energy generation. Our findings indicate that an optimized maintenance design with respect to the maintenance behavior of an HVDC energy export system can decrease the maintenance-related energy losses (indirect maintenance costs) for an offshore wind farm to almost one half. It was also shown that direct maintenance costs for the MMC (staff costs) have small effect on the total maintenance costs. This can be explained by the fact that the additional costs for maintenance staff are two orders of magnitude lower than the revenue losses during maintenance.
  
  
   
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2019

• Abdel-Khalek H, Schäfer M, Vásquez Torres RA, Unnewehr J, Weidlich A
  Forecasting Cross-Border Power Transmission Capacities in Central Western Europe Using Artificial Neural Networks
  2019 Energy Informatics, Band: 2, Ergänzungsband: 1, Seiten: 1 - 13
  
   
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2018

• Unnewehr J, Waldl H-P, Pahlke P, Herráez I
  Reducing operational costs of offshore HVDC energy export systems through optimized maintenance
  2018 17th Wind Integration Workshop