A new molten salt energy storage system developed by Danish and Swiss companies can store renewable energy for up to two weeks, powering thousands of homes.
A new molten salt energy storage system using melted salt could soon help solve one of renewable energy’s biggest problems. The technology can store power from solar panels and wind turbines for days or even weeks, then release it when needed.
Two companies, Denmark’s Hyme Energy and Switzerland’s Sulzer, are working together to build what they call the world’s largest salt-based energy storage system. When complete, it will store enough power to run around 100,000 homes for 10 hours.
Living in Europe, I’ve witnessed Germany’s push toward renewable energy. But anyone who pays attention knows the challenge: the sun doesn’t always shine, and the wind doesn’t always blow. This molten salt energy storage technology could be a game-changer for countries like ours that rely heavily on renewable energy.
The system works by heating ordinary salt to extremely high temperatures. When electricity flows in, it is converted to heat, which warms the salt to around 600 degrees Celsius. That’s hot enough to melt aluminum. The melted salt can hold this heat for up to two weeks without losing much energy.
When power is needed, the hot salt flows through a steam generator. This creates high-pressure steam that can either run turbines to make electricity or provide heat directly to factories. The whole process captures about 90 percent of the energy put into it, which is remarkably efficient.
The salt they use isn’t table salt. Instead, it’s a type called hydroxide salt, which is a byproduct of the chlorine production process. This makes the raw material cheap and widely available. Using industrial waste as an energy storage medium also helps reduce overall environmental impact.
What makes this molten salt energy storage approach different from batteries is the scale and duration. While lithium batteries work well for storing energy for hours, this salt system can hold power for much longer periods. It can also handle the massive amounts of energy that entire neighbourhoods or industrial facilities need.
Early cost estimates suggest molten salt energy storage could compete favorably with other large-scale storage options. While lithium battery installations currently cost between $200 and $400 per kilowatt-hour of storage capacity, thermal storage systems like this one could potentially offer similar or better economics for long-duration applications.
Industries that need constant heat for their processes could benefit most from this technology. Food processing, chemical manufacturing, and paper production all require steady, high-temperature heat that this molten salt energy storage system can provide.
However, molten salt energy storage does have geographic considerations. The technology works best in regions with stable electrical grids and access to industrial infrastructure. Northern European countries, such as Germany, Denmark, and the Netherlands, appear well-suited for this technology.
Integration with existing renewable energy projects represents a major opportunity for molten salt energy storage. Large solar farms could pair thermal storage with their photovoltaic panels to provide power long after sunset. Wind farms could use the technology to smooth out irregular wind power, making it more predictable and valuable to grid operators.
The collaboration brings together expertise from two different fields. Hyme Energy specializes in thermal storage systems, while Sulzer has decades of experience with pumps and fluid handling equipment. Sulzer’s expertise includes supplying specialized pumps for concentrated solar power projects, including a major installation in China. The Swiss company’s understanding of high-temperature fluid dynamics and corrosion-resistant materials makes it an ideal partner for scaling up molten salt energy storage systems. This combination of skills could be crucial for scaling up the molten salt energy storage technology.
For countries committed to renewable energy, storage solutions like this represent a critical piece of the puzzle. Without effective ways to store power from intermittent sources, achieving high percentages of renewable energy becomes significantly more challenging.
Watching Germany’s energy transition unfold, I find this development encouraging. The molten salt energy storage technology seems ready for real-world deployment, and the potential benefits are substantial. The Danish companies are now working on an even larger project in Holstebro, which aims to be four times bigger than their current demonstration facility. This commercial-scale installation could save a major dairy cooperative millions in annual heating costs. If successful, it could help renewable energy finally fulfil its promise of powering our modern world reliably and sustainably.
