In recent years, the mainland's power supply has become increasingly sufficient, and large-scale power outages have been limited.
However, even a brief power outage can cause immeasurable damage.
In 2020, a sudden power outage at a wastewater treatment plant in California resulted in about 190 cubic meters of untreated wastewater being discharged directly into the Oakland River.
This reminds us once again that power plants are increasingly important in today's society where electricity is no longer necessary.
But many people wonder where does the electricity that can't be used up every day go?
The road to electricity is endless
Since ancient times, smooth transportation has facilitated economic development.
The take-off of contemporary China's economy is also inseparable from the "Information Silk Road" of a powerful power grid.
For decades, the builders of the China Power Grid Corporation have built a transmission network covering a vast territory, and the scale of China's power grid ranks first in the world.
You must know that the power grid is the economic lifeblood of the country, and a stable and reliable power supply is related to the national economy and people's livelihood.
The history of China's power grid construction can be traced back to the 50s of the 20th century, when the mainland was in a critical period of economic recovery and development.
In 1956, the Gezhouba power station was completed to generate electricity, marking the beginning of the establishment of a large-scale power system in the mainland.
Since the 60s, the Leningrad-style block power grid has gradually taken shape, providing reliable power supply for heavy industrial regions such as Northeast China and North China.
After the reform and opening up, the mainland's power construction has entered the fast lane, and large-scale power stations have sprung up.
With the implementation of large-scale cross-regional power transmission projects such as west-to-east power transmission and south-to-north power transmission, various regional power grids have begun to be interconnected, and a criss-crossing large power grid framework has been initially erected.
Since the beginning of the 21 st century, the mainland has put forward the strategy of "large-scale development of the western region" and vigorously promoted the construction of infrastructure facilities in the western region.
From 2005 to 2010 alone, China Power Grid Corporation invested more than 660 billion yuan in the construction of national UHV transmission projects.
Today, from Xinjiang and Qinghai to Guangdong and Shanghai, almost every province is connected to this huge power grid and shares the fruits of modern civilization.
In the project of bringing electricity to the countryside, whether it is a plateau village at an altitude of 4,000 meters or a Gobi in southern Xinjiang that stretches for thousands of miles, crystal poles have been erected.
With the rapid development of China's economy, the demand for electricity is continuing to rise.
In order to ensure power supply, China has vigorously developed the construction of power grids, and adopted a variety of means to ensure the safe and efficient operation of power grids.
From 2014 alone, the total length of high-voltage transmission lines of 220 kV and above reached 572,000 kilometers, which is nearly twice that of the United States, and the substation capacity is as high as 3.027 billion kVA, ranking first in the world.
Not only that, the construction of the power grid has also extended to remote areas, whether urban or remote rural, the coverage of the power grid has been expanding, so that more areas can enjoy the convenience of electricity.
At present, China's electricity is mainly coal-powered, but it is also vigorously developing clean energy.
With the adjustment of the economic structure, the demand for electricity may change greatly.
In order to ensure the safe and reliable operation of the power grid, we have also adopted flexible power plant frequency and voltage regulation methods for power distribution.
By accurately predicting the electricity consumption of each region in different periods, the large power grid takes turns to start and stop the generating units, reasonably allocate the baseload units and peak shaving units, adjust the power generation in real time, and ensure the balance between supply and demand.
It is worth mentioning that in order to ensure the normal operation of power grid equipment, China Power Grid Corporation has also invested a lot of manpower and material resources.
In order to regularly inspect and maintain, power grid technicians need to climb the power tower with their bare hands to operate the power transmission and transformation equipment in the power transmission and transformation equipment in the power system.
With the development of society, China's power grid construction is also constantly improving, on the one hand, the construction of smart grid in an orderly manner, mobile communications, cloud computing and other high-tech and power system deep integration, greatly improving the level of power grid monitoring and management.
Moreover, the market-oriented reform of electricity trading has been deepened, forming a relatively complete power market system, and the production and use of electricity are more efficiently coordinated.
However, many people wonder if we reduce the demand for electricity in our daily lives, where will the excess electricity go?
In fact, we don't have to worry about this at all.
Electricity storage mode
In order to cope with the timeliness of power supply and demand, China's power grid has adopted a variety of power storage methods.
Pumped hydro storage is one of the most widely used energy storage methods in China, which uses the difference between two reservoirs to pump water to a high reservoir for storage when electricity consumption is low, and opens the sluice gate to release water to generate electricity during peak power consumption.
This type of energy storage can quickly respond to large fluctuations in electricity demand, and China has built dozens of pumped storage power stations with a total installed capacity of more than 40 million kilowatts, accounting for more than one-third of the world's total.
Not only that, pumped storage has a high efficiency, which can reach more than 75%, which is currently the most economically advantageous energy storage method.
However, it needs to have certain topographical conditions, and it requires the construction of two reservoirs, which is more expensive to build.
With the increase in the proportion of renewable energy, pumped storage methods play a greater role in solving the randomness of wind power generation and photovoltaic power generation.
The southern part of the mainland is densely populated with rivers and abundant hydropower resources, which is conducive to the location of pumped storage sites, and the pumped storage power station has a short construction period and strong regulation capacity, which is the most widely used energy storage method at present.
In the future, with the increase in the proportion of distributed energy resources connected to the power grid, distributed pumped storage power stations will also develop rapidly.
Unlike pumped hydro, the battery directly stores the charge.
Lead-acid batteries have been used for a long time, but the efficiency is relatively low, while lithium-ion batteries have the advantages of small size and high power density, and are used in electric vehicles and other fields.
However, at present, the cost of battery energy storage equipment is high, and it cannot be promoted on a large scale, and some new battery technologies are also being developed.
In the future, with the popularization of electric vehicles, their batteries can realize the interaction between the Internet of Vehicles and the power grid, and become an important distributed energy storage resource.
Not only that, flywheel energy storage uses the rotor to rotate at high speed to store kinetic energy, which can also be used to store electricity.
Compared with pumped hydro storage, it is more efficient, even more than 90%, and the response speed is very fast, which is suitable for fast charging and discharging.
However, this storage capacity is very limited, mainly used for short-term high-power compensation, and cannot replace the main role of pumped storage in the power grid.
In addition to these technologies, supercapacitor energy storage is also developing rapidly, which uses capacitors to store charge, has a fast charge-discharge response, is suitable for short-term regulation of the power grid, and can also be combined with batteries.
Although supercapacitors have a long cycle life, their power storage costs are relatively high.
In recent years, some experts have proposed compressed air energy storage technology, that is, compressed air or other gases are stored in special gas storage tanks, and gas is released to drive turbines to generate electricity according to electricity needs.
It is important to know that gas energy storage has a fast response speed and can start and shut down in seconds, which is very suitable for rapid grid connection requirements in the event of transmission failure.
At present, the installed capacity of gas energy storage in mainland China is about 10MW, and typical projects include the gas energy storage power generation project in Zhangjiagang City, Jiangsu Province.
This energy storage method is safe and environmentally friendly, with a high number of reuses, and is one of the important energy storage technologies.
In general, pumped storage is the most important energy storage method in the continental power grid, but with the increase in the proportion of new energy generation, the demand for energy storage technology in the grid is also changing.
Various energy storage technologies have their own advantages, and when they are applied, they also choose the best energy storage solution according to the needs of the power grid in terms of response speed, storage capacity, cost, etc.
Grid-side energy storage technology helps upgrade China's power system
According to relevant data, China is in a critical period of energy revolution, and the power system is also facing profound changes.
In this context, grid-side energy storage has become an important means to promote the transformation and upgrading of the power grid by virtue of its technical advantages.
Grid-side energy storage refers to large-scale energy storage stations that are directly connected to the public power grid and can provide a variety of services to the power grid.
Compared with ordinary energy storage facilities, grid-side energy storage interacts with the grid in real time, and can accurately regulate charging and discharging, thereby improving the safety and flexibility of the power grid.
It can balance the load of the power grid through storage and discharge during peak and valley hours, improve the efficiency of resource utilization, provide power support in the event of failure, and ensure the safe and stable operation of the power grid.
As the share of renewable energy in China continues to increase, the power grid is facing greater volatility pressures.
At this time, the role of grid-side energy storage is very important.
In fact, grid-side energy storage has achieved a certain amount of technology accumulation as early as the 90s of the 20th century.
At that time, some developed countries began to study how to use energy storage systems to improve grid stability.
Since then, advances in power electronics have provided key support for grid-side energy storage.
After entering the 21st century, Germany, Japan and other countries took the lead in building grid-level energy storage demonstration projects, and these early practices have accumulated valuable experience for the commercial application of grid-side energy storage.
Since 2018, Beijing, Shandong, Jiangsu and other places have begun to build large-scale grid-side energy storage stations.
As the technology matures, grid-side energy storage is gradually playing a key role in the power Internet of Things.
It is believed that in the future, with the continuous research and innovation of experts, China's grid-side energy storage will move towards large-scale application and promote the upgrading of the power system.
However, in this process, it is still the responsibility of every citizen to save electricity.