By Felicity Bradstock for Oilprice.com| Many countries need to invest heavily in upgrading their electrical grid system, as vast quantities of renewable energy get connected, many from non-conventional energy-producing regions. In most countries, the transmission network was built several decades ago on older technologies, around conventional power plants in energy hubs. However, as countries increase their green energy capacity and decentralise energy production, most grid systems cannot cope with the influx of electricity from alternative regions at varying levels throughout the day.
Governments worldwide are developing plans to modernize or even overhaul their grid systems in line with green transition roadmaps, in preparation to connect more renewable energy projects to the grid. However, upgrading transmission networks does not have a one-size-fits-all approach, and it will likely require a range of different technologies and methods to match grid capabilities to the specific context.
A 2024 report by McKinsey states, “Grids were not originally set up for such a fast-paced energy system; their tools and processes were developed in a slower, less volatile world.” It adds, “Increased penetration of intermittent power sources, such as solar and wind, has caused a higher utility frequency and voltage volatility.”
One technology that is gaining traction in response to the problem is the solid-state transformer (SST). Researchers have been exploring the potential for SSTs since the 1960s, but the recent push to transition to renewable energy has spurred greater research and investment into the technology. Unlike conventional transformers that rely on heavy iron cores and low-frequency operation, SSTs use a multi-stage architecture and high-frequency transformer (HFT) to achieve significant improvements in size, efficiency, and functionality.
At the input stage, low-frequency alternating current (AC) is converted into direct current (DC), allowing for high-efficiency power management. Wide-bandgap semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN), provide reduced switching losses, enhanced thermal stability, and the ability to operate at higher frequencies, allowing SSTs to have a more compact design and greater power density. The input stage supports seamless integration with the grid, as well as stabilises power delivery.
During the isolation stage (high-frequency DC-DC conversion), an HFT isolates and adjusts voltage levels between the high- and low-voltage sides, minimising core losses. While at the output stage (DC-AC conversion), DC can be converted back into AC or kept as DC, depending on the application. Power can flow bidirectionally, while voltage and current regulation bolster grid stability and efficiency.
In recent years, there have been significant advancements in STT design and the materials used in construction, which have helped to enhance performance and applicability. Silicon carbide and gallium nitride provide the ability to switch frequencies, as well as offer improved thermal management and reduce energy losses. HFTs developed with advanced magnetic materials, like ferrites or amorphous alloys, help reduce the size and weight of SSTs, as well as maintain high power density and minimal energy loss. The improved design also enhances operational flexibility. In addition, there are now better cooling mechanisms, as well as advanced technologies, such as intelligent control algorithms, that can enhance function.
The global SST market is expected to achieve a value of $586 million by 2033, with a significant increase from $207 million in 2024 and growing at a CAGR of 12.27 percent. STTs are still largely in the research and development phase, although some pilot projects are being carried out to assess the viability of the technology.
In 2022, the U.S. Department of Energy provided the Taiwanese power electronics manufacturer Delta with a grant to test its 400-kW extremely fast EV charger, which uses SST technology. Delta partnered with General Motors and Virginia Tech to test the technology, which it found to have greater efficiency than conventional chargers.
Meanwhile, in Singapore, the startup Amperesand plans to commence a one-year proof-of-value trial in mid-2025 to test the use of SST technology at Singapore’s port. In addition, the EU’s SSTAR project has been conducting laboratory tests in Portugal and Spain, from which it plans to publish results in February 2026. The project managers aim to develop a new biodegradable dielectric fluid to support 50 percent CO2 savings when compared with traditional mineral oils, to enhance environmental sustainability.
However, to get to the point where SSTs are ready for a commercial rollout, developers must overcome several barriers. The main constraint for SSTs is price, as the technology is more expensive than that used in conventional transformers, which could deter governments and utilities from investing in the technology. However, greater investment in research and development from different world powers would likely lead to a decrease in production costs over time.
Investing in the research and development of solid-state transformers is just one of many ways that governments can support grid modernisation. In addition to strengthening transmission networks using conventional methods and technologies, greater innovation could help enhance grid systems for the years to come, as the energy sector continues to evolve.
By Felicity Bradstock for Oilprice.com
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