RockStore

Discover how we turn century-old techniques into high-efficiency heat storage solutions for modern-day companies.

This is how it works

Surprisingly simple and economical yet incredibly powerful, RockStore is the heat storage system industries around the world have been asking for.

Heliac’s RockStore solution uses granite rocks in large steel tanks to store heat up to 300 °C. Heat sources can be anything from a customer’s waste heat or heat generated from a Heliac solar field to excess renewable electricity. In other words, an incredibly versatile solution for a wide range of applications.

RockStore tanks are charged and discharged using an eco-friendly oil that interfaces with the user’s heat systems through a standard heat exchanger.

The system can be charged and discharged as required, allowing customers to use energy when it is most needed.

In larger systems, the storage solution can even include a steam turbine for power generation. Get in touch with us today to learn more about RockStore’s many applications.

Our ambitions

With RockStore, our ambition is to ensure that the industry receives precisely the energy it needs while reducing both investment and operating costs. Partnering with us means a solution that not only meets today’s demands but is also future-proof. RockStore provides a tailored thermal storage solution built on proven and reliable components.

Thermal storage is one of the few solutions that can be seamlessly integrated into renewable energy systems without major technical hurdles. Commercially, there is a growing market for this technology, especially among customers who want to maximize the use of renewable energy while maintaining a stable energy supply and achieving substantial cost savings. Heat storage is a well-established method where electricity is converted into heat using a heat transfer fluid to warm a thermal reservoir. The same fluid is then used to recover and deliver heat for industrial purposes.

Technical approach

We operate the storage system at temperatures up to 300 °C to keep costs low and ensure efficient heat storage while avoiding complications associated with higher temperatures in the heat transfer fluid. As a result, we can deliver usable heat of up to approximately 250 °C.

 

Strategy

  • We have developed a fully operational RockStore system that can scale to at least 100 MWh capacity.
  • RockStore technology has demonstrated cost efficiency significantly lower than traditional batteries, at just 10-15 €/kWh.
  • Our technology enables the direct integration of solar power systems without inverters, creating a fully local off-grid solution with minimal energy costs

Design philosophy
To deliver a reliable system for users with heat requirements up to 300 °C, we have made the following design choices:

  • Use of well-established components from reputable suppliers.
  • Limiting maximum temperatures to minimize thermal and material challenges and allow the use of non-freezing heat transfer fluids, such as molten salts.
  • Natural stones, like granite, are used as the heat storage medium, chosen for their availability, scalability, environmental friendliness, and cost-effectiveness.

Financing options

Turnkey delivery

With an emphasis on high quality, cost-effectiveness, and on-time delivery, we offer turnkey solutions in markets worldwide.

Our full range of services includes – but is not limited to – site assessments, and distribution design, cabling, installation, testing, and project management. In short, everything needed to get your Heliac system up and running safely and on time.

Heat purchase agreement

We are pleased to offer alternative financing through a Heat Purchase Agreement (HPA) to customers looking for a less capital-intensive solution to their new system.

 

Contact

Get in touch and hear how we help decarbonize your heat supply!