1. What is long-duration energy storage?
Long-duration energy storage is a relatively new concept. Simply put, it refers to storing energy for a longer period, such as several hours or even weeks.
Of course, different countries have different standards for long-duration energy storage. As stated in the “ISSUE BRIEF Long-duration Energy Storage” released by Sandia National Laboratories in 2021, long-duration energy storage refers to energy storage technology with a continuous discharge time of not less than 4 hours. This standard is widely used in many countries and regions around the world.
2. Implementation methods of long-duration energy storage technology
2.1 Physical energy storage
The technology of physical energy storage is very mature, and common ones in daily life include pumped storage and compressed air energy storage. These physical energy storage technologies can store energy for a considerable period.
However, compared to other methods, physical energy storage is more affected by geographical environment. Take pumped storage as an example, you need a geographical location that can store a large amount of water and has a certain drop, but there are not many conditions for such construction.
2.2 Chemical energy storage
The main implementation method of chemical energy storage is flow batteries. Flow batteries refer to a type of rechargeable battery that uses chemical reactions between electrolytes to store and release electrical energy.
Unlike electrochemical cells, flow batteries do not have solid-state electrode materials. Common flow batteries in daily life include vanadium redox batteries and zinc-bromine flow batteries. Compared to electrochemical cells, flow batteries have lower energy density and require higher initial investment costs.
2.3 Electrochemical energy storage
Electrochemical energy storage is the most common long-duration energy storage method in daily life, including lithium-ion batteries and lead-acid batteries.
Compared to other cells, the energy density of these electrochemical cells is higher and very convenient. Suitable for many scenarios, such as home energy storage, small and medium-sized energy storage systems, and large-scale energy storage systems.
3. Advantages of long-duration energy storage
3.1 Reduce electricity bills
Long-duration energy storage can reduce electricity bills to a certain extent. Under normal circumstances, electricity prices may vary at different times.
Generally speaking, electricity prices during peak periods are much higher than during low periods. So you can use lithium-ion batteries to store electricity at lower prices and take it out for use at higher prices. In this way, long-duration energy storage can help you save some electricity bills.
3.2 Improve energy utilization efficiency and environmental friendliness
Long-duration energy storage can effectively store the excess electricity generated by renewable energy generation systems. This can not only reduce the waste of electricity but also improve the utilization of energy. It can also concentrate the electricity converted from renewable energy for equipment use. This has to some extent reduced the emissions of greenhouse gases and pollutants, which has a promoting effect on environmental protection.
3.3 Improving the stability of power supply
Long-duration storage plays an important role in improving the stability of the power supply. Especially for renewable energy generation systems in special environments (such as solar power systems encountering rainy weather) and abnormal situations in the power grid. In these cases, long-duration energy storage can timely supply the normally stored electrical energy to the equipment to ensure its normal operation for a while.
So, if you are in an area prone to power outages or frequent rainy weather, it is necessary to equip your solar system with a suitable solar cell to ensure the stability of the power supply.
4. Common questions
4.1 How to choose a suitable long-duration energy storage method?
Firstly, you need to determine the application scenario. For example, if you need to choose a suitable long-duration energy storage for your solar system, and your electricity demand is high, then physical energy storage is not practical. Compared to others, lithium iron phosphate batteries would be a good choice because of their high energy density. Of course, if your initial budget is not sufficient, you can choose lead-acid batteries.
Secondly, you need to consider the surrounding environment. For example, if you are in an area with harsh environmental conditions, lithium-ion batteries are a better choice. Because physical energy storage requires a specific geographical location, lead-acid batteries are more susceptible to environmental influences when using long-duration energy storage methods.
Finally, you need to consider quality issues. The quality of branded products is more guaranteed compared to ordinary products, and different long-duration energy storage methods will have different brands. Take lithium-ion batteries as an example, well-known brands such as CATL, GuoXuan High Tech, and BYD are all producing lithium-ion batteries, and you can choose the product that suits you.
5. Summary
Long-duration energy storage is a very important technology that has significant implications for promoting the development of human society. Through an in-depth understanding of long-duration energy storage, it is beneficial for you to build a suitable energy storage system and arrange your electricity usage reasonably. Of course, before choosing a long-duration energy storage method, you must consider multiple factors, which can help you find the most suitable method for you.
