The need to store energy from solar panels and wind turbines in an efficient and flexible way will increase significantly in the coming years. There are advantages in storing renewable energy and saving it for later use when there are peak loads on the grid and when renewable energy production is low. That is why the Danish company Aalborg CSP, a specialist in renewable energy, sees great potential in building storage facilities that promote the energy transition.
Aalborg CSP has developed an innovative solution that transforms existing coal-fired power plants into large-scale energy storage facilities. With many of these plants scheduled for decommissioning as part of the global green transition, Aalborg CSP’s approach offers a smarter alternative: rather than dismantling existing infrastructure, the solution reuses most of the installed equipment, preserves local jobs, and provides cost-effective energy storage and regional security of supply of electricity and heat. Drawing on proven large-scale applications, the concept enables continued use of existing sites for energy purposes, while allowing new energy storage infrastructure to be built where needed most.
In Europe, there are more than 250 operating coal-fired power plants that are having an impact on the environment and climate due to their high consumption of fossil fuels. Many of these power plants will be phased out because the CO2 emissions must be reduced significantly in the coming years, which means that power plant owners will be left with outdated facilities resulting in large depreciation charges if they are not converted to electric storage operation.
At Aalborg CSP, Vice President of Technical Sales, Jens Taggart Pelle, hopes that, in addition to the environmental and climate related benefits, owners of coal-fired power plants will also see a good business opportunity in replacing the boilers at coal-fired power stations with energy storage facilities powered by cheap electricity and revenue from the provision of grid system services.
“The plant owners will save on the costs of decommissioning and dismantling coal-fired power plants, which are scrap if they can no longer generate power,” says Jens Taggart Pelle. “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. 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 provision of 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, thanks to the conversion, provide security of supply of electricity in unstable times while making a huge effort in creating sustainable future energy production.”
Innovative power-to-salt concept
Aalborg CSP aims to convert coal-fired power plants to energy storage by offering power-to-salt technologies. 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 565°C. 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 – eliminating the need for fossil fuel combustion. By using Aalborg CSP’s 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 be able to retain local jobs at power plants and turn them into ‘green’ jobs, focused on the operation and maintenance of converted coal plants.
“We have a proven concept that can be scaled as needed. I believe there is a great need for policies that promote large-scale energy storage as part of our grid infrastructure utilising 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”, argues Jens Taggart 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 Corporation, to explore the possibility of converting a large coal-fired power plant in Bulgaria to energy storage. The power plant, Galabovo TPP, was only built in 2010, but AES is considering converting it into a greener 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. 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 existing infrastructure thereby securing the long-term viability of the asset while continuing to deliver reliable, clean energy to Bulgarian consumers for decades to come” says Ivan Tzankov, President AES Bulgaria.
Aalborg CSP hopes that the potential plant conversion in Bulgaria might pave the way for collaboration with other owners of coal-fired power plants. The company believes that we will see the emergence of this technology in Europe within a few years.
For further information, contact: Jens Taggart Pelle, Vice President of Technical Sales, Aalborg CSP, phone: +45 30 80 69 10, e-mail: jtp@aalborgcsp.com
