The cost-efficient energy storage scheme can be said to be the key to the gradual transition of mankind to a low-carbon society, and there are two main ways to store energy, one for storing heat and one for storing electricity.
So which of these two forms of energy storage is more economical? A new study released recently by the German Energy Storage Association (bves) shows that lithium-ion batteries cost about 33 times times the cost of molten salt storage when storing 1kWhel and 1kWhth respectively.
"Detailed data is shown in the table below"
Table: Comparison of energy storage costs (data from a number of German-language sources, calculated as total capital expenditure divided by the total amount of storage or heat in a work cycle, in which the cost of the lithium-ion battery storage Project also includes the cost of infrastructure such as air-conditioning and fire prevention measures). As the table above, Bves said, it is necessary to note that, whether direct heat transfer or indirect heat transfer, depending on the temperature difference and operating mode, the specific cost will be different, therefore, the data provided by the cost data range between 25-70 euros/kwhth.
The six model systems using large lithium batteries (built by STEAG, the energy supplier) cost up to 833 euros/kwhel. According to the data of the above table, the cost of molten salt storage has obvious advantage compared with the cost of lithium battery. Concurrently the German Enolcon and Storasol two companies "Enolcon is an engineering consulting firm that specializes in project financing and evaluation support services for the various renewable energy facility developers of traditional power plants;" Storasol Company was founded in 2013, relying on the technology developed by Enolcon Company to design high-temperature thermal storage System.
Dr. Günter Schneider, general manager, agreed with the above figures. Schneider that cost comparisons have always been a tricky issue because they depend largely on what devices are involved in basic computing, such as fans, heat exchangers, pumps, and so on. If the initial cost is the same, when the temperature can affect the size of the heat storage capacity, the cost per kilowatt hour will depend on the storage temperature.
For example, when the heat storage temperature reaches 550 ℃, the heat storage capacity is about 440 ℃ twice times, so the energy storage cost per kilowatt hour can be reduced by half. Schneider also pointed out that technological innovation is making the cost of heat storage further decline. For example, the Storasol Company's new modular technology enables the storage of more than 600 ℃, which uses gravel or gravel to store heat and uses outdoor air for heat transfer. The innovative solid state heat storage medium is arranged according to the bed type, which can realize rapid heat storage and release heating. The large surface area can reduce the air velocity and minimize the pressure loss of the whole operating system. By calculation, the cost of heat storage can be reduced to 15~25 euro/kwhth.
At the end of 2015, the first megawatt system using the technology had been put into operation at Ruter University in Germany.
And for the development phase of the photovoltaic power generation industry, the molten salt storage system has gradually become the standard configuration of thermal power station, the industry is recognized that a high economic temperature of the molten salt storage system will undoubtedly play a positive role in the future development of the light thermal power generation industry.
Table: Main parameter indices of molten salt thermal storage System (Data source: bves) In particular, molten salt is the most popular heat storage medium used in large thermal power plants, and the high cost performance of molten salt storage system is the important guarantee for the thermal power plant to achieve long time stable power generation without the help of fossil fuel.
