Energy Utilization

Medium Voltage – Energy Utilization
© Fraunhofer ISE

In addition to large-scale PV power plants, other interesting applications for the medium voltage range are large-scale heat pumps for industry as well as railway and shipping applications. 


Electric mobility is by no means a modern phenomenon, as the example of electric train use since the 19th century makes clear. Nevertheless, many railroad lines are still not electrified today and operate instead with diesel locomotives. The direct feed-in of PV electricity into the rail network is a good option for an emission-free future for rail lines. The rail network operates in the medium-voltage range and therefore requires efficient converters in order to efficiently feed in energy generated in the low-voltage range. In addition, elongated photovoltaic systems that are installed along railroad lines offer similar savings in terms of material resources as a large PV power plant of the same size, especially if it is designed as a medium-voltage power plant.

In the shipping sector, the International Maritime Organization (IMO) is aiming to reduce annual greenhouse gas emissions by at least 70 percent by 2040. As a result, environmental regulations for maritime transport are becoming increasingly stringent and the transition to sustainable maritime solutions is in full swing. Hybrid solutions and electric propulsion are becoming the preferred choice for many types of ships and ferries, especially those operating close to shore and on inland waterways. Here, too, medium voltage as a technology offers considerable savings potential at system level and can significantly advance decarbonization in shipping.

Large-Scale Heat Pumps

In Germany, a large proportion of CO2 emissions are attributable to the heat supply. However, industrial heat pumps, operated with emission-free electricity, can make a sustainable and economically effective contribution to decarbonizing the heat supply.  Compared to smaller, decentralized units, large-scale heat pumps for industry have the advantage that they can utilize large natural heat sources as well as industrial waste heat with high energy potential at low temperatures. Especially in very large industrial plants with wide expanses and a high demand for process heat, a more efficient and material-saving energy transfer can be realized by combining local renewable power generation plants with large heat pumps via a medium-voltage DC bus system.

R&D Services

We provide R&D services for manufacturers of traction power supplies, components and systems for MVDC grids, large-scale industrial heat pumps, energy suppliers, transmission system operators, power plant operators as well as project developers, system integrators and system manufacturers. Our range of services includes:

  • Development of efficient high-power converters for low and medium-voltage applications
  • Feasibility and concept studies for high-power electronic systems
  • Advice and expert opinions on power electronic issues
  • Component and device development for heat pumps
  • Climate-friendly refrigerants for heat pumps
  • System analysis and optimization of heat pumps
  • Troubleshooting and error analysis in the lab and on the field

Our R&D Infrastructure on this Topic


Center for Power Electronics and Sustainable Grids


Center for Heating and Cooling Technologies

Examination and characterization of equipment and components for use in building services engineering


TestLab Heat Pumps and Chillers

State of the art technology for developing, measuring and characterizing heat pumps and chillers, as well as their components

Selected Research Projects



Bidirectional Medium-voltage Converter with High-voltage SiC Devices for Increased Integration of Renewable Energies and Inner-city Storage in Innovative Grid Structures


Living Laboratory on Large-Scale Heat Pumps

“Large-scale heat pumps in district heating networks - installation, operation, monitoring and system integration"

Further Information on this Research Topic:


Power Electronics and Grids


Climate-Neutral​ Heat and Buildings