By zhanqun1 
Have you ever thought that wind and photovoltaic power generation are like two “depending on the sky to eat” masters? When there is no wind, the fan will not cook;
When the sun goes down, the photovoltaic panel “touches the fish.”. The requirement for electricity will not take God’s face into account, the lights need to be turned on at night, and the mobile phone needs to be swiped. So the question is: how do you make these “scenic” sources of energy reliable? The answer is energy storage!
1. What is energy storage? In simple terms, “save electricity.”
Energy storage, as the name implies, is to save electricity and use it when you need it. Like you save up snacks, take them out whenever you are hungry. For wind and photovoltaic power generation, energy storage is their “charging treasure”, saving up excess electricity and then letting it out when there is no wind and no sun.
2. what are the “charging treasures” of wind and photovoltaic power generation?
Nowadays, there are some mainstream energy storage methods, let’s pick some interesting ones to say:
- Battery energy storage: the “mobile hard disk” of the power industry
Battery storage is the most common way, like the lithium battery in your phone, to store the energy in and take it out when you want to use it. These days commonly used batteries are lithium batteries, sodium ion batteries, etc. They are characterized as flexible, efficient, and suitable for small-scale energy storage.
Advantages: Anytime, anywhere, simple to install.
Disadvantages: High cost, short lifespan, just like your cell phone battery, will degrade after a long time.
- Pumped Storage: The “reservoir” of the power industry
Pumped storage is one of the oldest forms of energy storage. The principle is simple: excess electricity is used to pump water from low points to high points and store it. When electricity is needed, the water is drawn down and the turbine is turned to generate electricity.
Pros: large scale, low cost, can be applied to large-scale energy storage.
Cons: limited by certain geographical conditions, such as mountains and water, not every place can be built.
- Compressed air energy storage: the “pump” of the power industry
It’s somewhat similar to inflating a balloon. Extra energy is invested in compressing up the air and forcing it into underground chambers or tanks. Then, when energy is needed, the compressed air is released to drive a turbine to generate electricity.
Pros: Large scale, appropriate for long term energy storage.
Cons: Fairly inefficient, along with requiring specific geological conditions.
- Flywheel energy storage: the “top” of the power industry
Flywheel energy storage is neat, the concept is to use electrical energy to drive a high-speed rotating flywheel, the electrical energy into kinetic energy storage; When requiring electricity, it converts kinetic energy into electricity.
Advantages: Fast response, suitable for short time and high frequency charge and discharge.
Disadvantages: small scale, costly, more of a “top toy in the power industry.”.
3. the new darling of energy storage technology: hydrogen energy
Besides the above, there is a futuristic energy storage form – hydrogen energy. Its principle is to utilize surplus electricity to electrolysis water, generate hydrogen, and then store the hydrogen; When requiring electricity, hydrogen is transformed into electricity by a fuel cell.
Advantages: Hydrogen energy density is high, suitable for long-term, large-scale energy storage.
Disadvantages: The technology is immature, the cost is high, and the safety needs to be further verified.
4. the importance of energy storage: make the “scenery” energy more stable
The emergence of energy storage technology has made wind and photovoltaic power generation change from “depending on the sky” to “independence”. It not only addresses the problem of power supply and demand imbalance, but also improves the stability and reliability of the power grid. For example:
Cut the peak and fill the valley: store the excess electricity of photovoltaic power generation in the day and reuse it at night.
Emergency backup: In the event of harsh weather or collapse of the power grid, the energy storage system can fill in the gap immediately.
Eliminate waste: Excess electricity that would have been wasted otherwise before can now be stored and used progressively.
5. The future of energy storage: cheaper, more efficient and more environmentally friendly
With the development of technology, the cost of energy storage is becoming less and less expensive each year, and the efficiency is also improving. In the future, we may even have more innovative methods for storing energy, such as:
Supercapacitor: Very high charging and discharging rate, perfect for temporary high power requirement.
Liquid air energy storage: the air is liquefied and stored, and re-gasification to generate electricity when needed.
Bioenergy storage: Using microbes to convert electrical energy into bioenergy sounds sci-fi, right?
Wind energy and photovoltaic energy are the future of clean energy, but the “weather dependent” characteristic of these technologies determines that energy storage technology is indispensable. Whether batteries, pumped storage, or hydrogen energy, flywheel energy storage, each technology is contributing to the stable supply of “scenery” energy. In the coming years, with the relentless development of technology, energy storage will be more efficient and economical, and clean energy will really become an integral part of our lives.
So the next time you see a wind turbine spinning, or a photovoltaic panel sparkling in the sun, don’t forget that behind them is a group of unsung dedication of “charging treasure”!