Solar energy storage is a way to collect the energy produced by solar panels, convert it into another form of energy (chemical, thermal, mechanical, etc.) and release it when energy is needed. However, the storage of energy will not be 100% efficient, there will be energy loss in the process of conversion and recovery of energy, which requires us to choose an efficient storage method, and can improve the quality of electricity by matching the demand.
The battery is currently one of the most commonly used solar energy storage methods, solar energy through the MPPT (solar controller) or PWM (pulse controller) and solar inverters, the power will be charged into the battery, the battery module will be a chemical reaction to store energy. When power is needed, the chemical reaction within the battery reverses, allowing current to flow out of the battery. Currently in the market mainly use lead-acid batteries, lithium-ion batteries (lithium iron phosphate batteries), etc. We recommend the use of lithium iron phosphate batteries, mainly because of the advantages of lithium iron phosphate batteries such as high safety, not easy to thermal runaway, long cycle life, protection of the environment and so on, which can satisfy the conditions for storing solar energy.
Thermal energy storage is a technology that mainly utilizes various media (such as water or molten salt) to absorb and save heat from the sun, this heat storage material (generally molten salt) is stored in insulated tanks, and the energy in the storage tanks can be used for heating and cooling as well as power generation. For example, when power generation is needed, the molten salt is pushed into a steam generator, which boils the water to produce steam, which drives a turbine to turn up and produce electricity. This method provides a stable power supply and is ideal for places where solar radiation fluctuates, but the disadvantage is that the tanks need to be very large, and the upfront investment cost is very high.
Mainly using the potential energy of the object to generate electricity, the excess electrical energy of the solar system into mechanical energy, when we need electricity, can be converted into mechanical energy for us to use, there are mainly three kinds of mechanical energy storage system:
3.1 Flywheel storage
Flywheel is a heavy-duty wheel mounted on a rotating shaft, which utilizes the principle of kinetic energy to store and release energy. When there is excess energy from the sun, it is used to rotate the flywheel to convert electrical energy into kinetic energy, and when we need to use the electricity stored in the flywheel, the rotating flywheel is connected to a generator that converts the kinetic energy into electrical energy for our use.
3.2 Pumped storage
Pumped storage is to transfer the excess energy from solar energy to pumps, pumping water from lower reservoirs to higher reservoirs, and when the demand for electricity is too high, the stored water can be released from higher reservoirs to lower reservoirs, pushing the turbine to rotate and generate electricity to meet our power needs. This method of energy storage mainly uses conventional energy sources for power supply, solar systems have limited power supply unless large solar systems are used for power supply, apart from that this method of energy storage requires a lot of cost investment upfront.
3.3 Compressed air storage.
This is an innovative solution that utilizes excess solar energy to compress air and store it in high-pressure tanks. When energy demand is high, the compressed air is released and the expanding air pushes a turbine to generate electricity to meet the power demand.
4. Hydrogen storage through electrolysis.
Hydrogen has become a versatile clean energy source, and generating hydrogen through electrolysis can provide an attractive solar energy storage solution. Excess solar energy is used to electrolyse water to produce hydrogen and oxygen, and then the hydrogen is stored and used in fuel cells to generate electricity when needed. This method has the potential to be a long-term energy storage and transportation application, providing a solar energy storage method.
We recommend the use of lithium iron phosphate batteries for solar energy storage, on the one hand, lithium iron phosphate batteries have high safety and long service life, on the other hand, the cost of using lithium iron phosphate batteries for storage is lower than the cost of mechanical storage and thermal energy storage, when choosing a solar energy storage solution, you can choose the most suitable solar energy storage solution according to your own needs or relevant policies.
