Hybrid Power Plants

Higher system voltages enable completely new system architectures for renewable hybrid power plants, whose individual components are linked together in a resource-efficient manner via the medium voltage. This allows system approaches for hybrid power plants and the integration of decentralized energy provision to be rethought and enables more resilient power supplies for districts, charging infrastructure or industrial operations with reduced dependence on the traditional power grid. 

PV Battery

The expansion of large stationary battery storage systems has an enormous potential, particularly in combination with photovoltaic power plants. In a PV-battery plant, electricity can be fed into the interconnected grids when in demand and thus in a yield-optimized manner. Also, large-scale storage facilities can be set up at former fossil-fuel or other conventional power plant sites so as to make use of the existing grid connections. Such large-scale storage facilities will play an important role in the resilience of the electricity supply of the future.

In the short study "Battery storage at former power plant sites", Fraunhofer ISE examined the systemic and grid-related benefits of large-scale storage systems. One of the results: Installing battery storage systems at former fossil fuel or nuclear power plant sites makes sense, as the connected load already available there can be used. This could cover up to 65 percent of the storage requirements needed in Germany by 2030.

PV Mobility (Rail)

The current rail traction network extends over 8,000 kilometers with its own power lines. These cover almost all of Germany and are operated at a specific frequency of 16.7 Hertz. The areas next to the tracks offer enormous potential for PV installations. However, a cost-efficient system technology to technically exploit this potential away from the usual 50 Hz feed-in points is currently lacking, although it is principally possible.

PV Battery Charging Infrastructure (Charging Hubs)

The transition to electric vehicles will be accelerated by the CO₂ reduction target and the EU registration change from 2035, according to which only new cars with combustion engines that no longer emit CO₂ while driving can be registered. While intensive research is being carried out on vehicles and charging systems, little attention is paid to the connection between the charging station and the public grid and to the required provision of power. This presents both challenges and opportunities for high-power electronic systems. Currently, cars are able to be fast charged with up to 850 V_DC / 350 kW. In future, however, trucks will be able to be charged with up to 1250 V_DC / 3 kA_DC in accordance with the MCS standard.

The study "Einfach Laden an Rastanlagen" (Easy Charging at Service Areas) by the German National Center for Charging Infrastructure deals with the power requirements of electric charging stations. The study takes into account different vehicle classes, traffic junctions, simultaneity factors and power prioritization and also assumes 50% electrified truck traffic by 2035. The study found that fast-charging systems with capacities ranging from 8 MVA (previously unmanaged, simple parking lots along the highway with seating) to 26 MVA (large rest and car stations at international junctions and highway sections with high traffic volumes) will be required in the future.  The requirement for a charging facility for trucks and cars at least every 50 km along Germany's freeways, which cover a total of around 13,200 kilometers, translates to a total installed charging capacity in the high double-digit gigawatt range. This estimate does not include large electric charging stations in urban areas and charging stations at trucking companies. For large truck stops with up to 150 parking spaces, the charging capacities at night can add up to 5-7 MVA, depending on the assumed simultaneity factor.

To relieve the load on the grids, a combination of storage and renewable generation directly on site is a promising solution. Parking lot roofs offer a large PV potential here. However, the connected load must also be distributed on site and routed to the individual charging points. To achieve a high level of efficiency and limit the use of materials, the move to medium voltage offers a sensible approach. As PV, storage and charging technology are DC-based, an MV-DC bus system would probably be the most efficient solution in the future.