Innovative tank for storing thermal solar energy could boost uptake
CSP uses a mirror configuration to concentrate the light energy onto a receiver and convert it into heat, which is then used for industrial processes or to drive a turbine. Unlike other renewable sources like wind power, it can produce power on demand since it can be equipped with thermal energy storage systems. However, the current high cost of solar thermal-generated electricity is one major disincentive to these technologies being adopted more widely. The EU project TANKRETE set out to tackle that challenge, carrying out a feasibility study for an innovative tank for storing thermal solar energy that is 20 % cheaper than current tanks on the market and longer lasting. “TANKRETE will contribute to the reduction of construction and operation and management costs, increasing the efficiency of CSP generation,” says David Ramirez Bertelli, technical director at Spanish engineering company Increscendo, which ran the project. “It will positively affect the decarbonisation of the EU’s energy system and contribute to a cleaner, secure and affordable energy supply, as proposed by the European Green Deal.” Current steel tanks containing the molten salts used in CSP plants are costly and, even though they are designed to last 25 years, often unreliable because their steel plates and welding cords corrode, and cracking appears at high temperatures. Their clay foundations also settle over time, allowing the molten salts to leak out. “The first plants in operation are beginning to experience structural problems, causing stoppages that can last nearly 1 year,” says Ramirez.
Multipurpose tanks
TANKRETE’s new molten salt tanks can be cylindrical or prismatic-shaped with an isolating foundation system made from patented thermal concretes. There are air chambers inside the foundation to mitigate energy loss. Its thickness and stiffness is more stable and not prone to corrosion, says Ramirez. The design has attracted interest from leading players in the energy sector like China’s Supcon and Power China, Denmark’s Aalborg, and Spain’s Acciona and Abengoa. Ramirez was invited to present the tanks at the CSP Focus Innovation conference in October. Increscendo has tendered to install its tanks in different CSP projects in China and Saudi Arabia. The tanks could also be used outside the CSP sector in any plant using thermodynamic processes at high temperatures. They could be fitted into any size factory, aerial or buried, even if already in operation. “With our ‘power units’ it is possible to store thermal energy to be used in other processes,” says Ramirez. “This energy could be ‘waste energy’ generated by the plant coming from stacks or ovens, for example.” Partly as a result of the commercial interest drummed up during the project, Increscendo estimates that it will grow turnover from EUR 0.4 million (2018) to almost EUR 131 million (2026) and increase staff from 3 to 20. “The TANKRETE project was a unique chance for us to begin leveraging the investment we needed and that the markets didn’t provide us,” says Ramirez.
Keywords
TANKRETE, Concentrating Solar Power, energy, CSP plants, thermal energy storage systems, molten salt tanks, thermal concretes
