Officials with Denmark-headquartered Aalborg CSP said the company has developed technology that could convert retired coal-fired power plants into thermal storage facilities for renewable energy.
The company in a news release on October 28 said that as existing coal-fired power plants are phased out, “It is ideal to re-use coal-fired power plants for storing renewable energy instead of demolishing them and building new energy storage facilities from scratch.”
Aalborg CSP said it has developed a solution that transforms existing coal-fired power plants into large-scale energy storage facilities. The company said its technology would reuse most of the facility’s installed equipment, enabling continued use of existing power generation sites to produce more energy.
The company said more than 250 coal-fired power plants in Europe could be phased out as part of emissions reductions strategies. Jens Taggart Pelle, Aalborg CSP vice president of Technical Sales, said that in addition to the environmental and climate-related benefits of plant closures, the owners of coal-fired power plants could enable a new business opportunity by replacing coal-fired boilers with energy storage facilities.
“The plant owners will save on the costs of decommissioning and dismantling coal-fired power plants, which are scrap if they can no longer produce energy. Our calculations show that repurposing coal-fired power plants is the most cost-effective solution, as the equipment is already installed and fully functional for many years to come,” said Pelle. “In addition, the plant owners will see a reduction in fuel costs by charging with excess renewable energy from the grid and can generate new revenue both through balancing services to the electricity market and arbitrage with the sale of the stored electricity. Likewise, we see the owners’ public image will be boosted as they through the conversion provide security of supply of electricity in unstable time while making a huge effort in creating a sustainable future energy production.”
Power-to-Salt Solution
Aalborg CSP can convert coal-fired power plants by offering what the company calls Power-to-Salt solutions. Using a so-called Carnot battery, Aalborg CSP can convert electricity into thermal energy. The battery works by converting excess electricity from green energy sources such as wind turbines and solar panels into heat. The heat is then stored in molten salt. When demand for electricity increases, the heat is converted back into electricity.
As part of the conversion, the coal-fired boiler is replaced with a steam generator system based on Header & Coil technology, powered by hot molten salt heated up to 565C. The molten salt is stored in two insulated tanks and used to generate high-temperature, high pressure steam, which drives the existing power plant turbines to produce electricity and eliminates the need for fossil fuel combustion. By using the Aalborg CSP storage technology, it is therefore possible to strengthen security of supply and create a balance between supply and demand.
Existing equipment such as steam turbines, generators and heat exchangers, as well as components for switching, transforming and transmitting high-voltage electricity, can be reused in the new energy plant.
In addition, it is also a major advantage to retain local jobs at the power plants and turn them into clean energy jobs in the operation and maintenance of the future plants.
“We have a proven concept that can be scaled as needed. I believe there is a great need for decisions that promote large-scale energy storage as part of our grid infrastructure utilizing energy from wind turbines and solar panels. It is essential that the transformation of power plants into green energy storage facilities should be given greater political focus in the coming years,” said Pelle.
Converting a Coal-Fired Power Plant in Bulgaria
Aalborg CSP is, among others, collaborating with AES Bulgaria, the Bulgarian affiliate of the American energy group AES Corp., to explore the possibility of converting a large coal-fired power plant in Bulgaria. The power plant was built in 2010, but AES is considering converting it into an energy storage facility.
“Our state-of-the-art coal-fired power plant represents valuable infrastructure for the country and we are actively working on a solution that aligns with European and Bulgarian energy transition goals,” said Ivan Tzankov, president of AES Bulgaria. “This transformation would enable more renewable energy to be integrated into the market by storing surplus production and releasing it when demand is high. The conversion of our power facility into an advanced energy storage plant would reuse most of the exisiting infrastructure thereby securing the long-term viability of the asset while continuing to deliver reliable, clean energy to Bulgarian consumers for decades to come.”
—Darrell Proctor is a senior editor for POWER.
