Researchers at the Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) in Germany have pioneered a new approach to large-scale solar power generation by building the first medium-voltage photovoltaic (PV) plants that use 3 kV string inverters. The breakthrough represents a potential step forward in reducing material and investment costs for future solar installations.
Traditional solar power plants typically operate at lower voltages, meaning they require extensive cabling and a large number of transformers. By increasing the voltage at which solar panels operate on the direct-current (DC) side, Fraunhofer’s “PVgoesMV” project aims to streamline system design and cut the amount of copper and aluminium needed for cabling and substations. This can lead to significant resource savings and lower overall project costs.
What the New Technology Involves
The medium-voltage solar plants under construction will operate with a DC voltage of 3 kV and an alternating-current (AC) voltage of about 1.2 kV. To achieve this, Fraunhofer ISE has adapted and scaled up silicon carbide-based inverters — devices that convert electricity from solar panels into grid-compatible power.
Two pilot solar sites are being built in German states with a connected load of approximately 135 kilowatts each. The project will test two configurations: one using standard modules at 1,500 V with centre-point grounding, and another using bespoke PV module prototypes designed specifically for higher voltages. The aim is to gather operational data to guide future product design and technical standards for medium-voltage PV systems.
Benefits of Medium-Voltage PV Systems
Shifting to medium voltage offers several potential advantages for solar power deployment:
- Reduced material use: Higher DC voltage allows thinner cabling, cutting down the amount of copper and aluminium required in large plants.
- Lower investment costs: With fewer transformers and simpler electrical infrastructure, total project costs can be reduced.
- Better scalability: Medium-voltage systems can be more easily adapted for large-scale and distributed solar installations.
- Industry collaboration: The project brings together multiple component manufacturers and engineering partners, accelerating the development of voltage-resistant components and testing protocols.
Towards a More Efficient Solar Future
The PVgoesMV initiative reflects broader efforts to improve the efficiency and cost-effectiveness of solar power technology as the world scales up renewables. By demonstrating that medium-voltage operation is technically feasible and economically viable, Fraunhofer ISE hopes to pave the way for new solar system architectures that reduce resource use, simplify installation and support long-term adoption of clean energy.
As solar capacity continues to grow globally, innovations like medium-voltage string inverters could play a key role in making renewable energy more affordable and sustainable at scale.
