Electric cars turn into "power banks": The energy revolution behind car owners' zero-cost car use

At noon on July 4th, the temperature in Wuhan soared to 39°C, and the roar of air conditioners echoed one after another. On this day, the power grid load in Wuhan reached 17.048 million kilowatts, a year-on-year increase of 26.48%, setting the first load peak of this year - 20 days earlier than last year. On the same day, the total load of the national power grid also climbed to a record high of 1.465 billion kilowatts, and the power grids in provinces such as Jiangsu, Anhui, and Shandong successively "hit the ceiling".

State Grid invested 30.3 billion yuan in 140 projects to ensure power supply during the summer, but still couldn't withstand the onslaught of high temperatures. 90% of the load increase in the Jiangsu power grid comes from air - conditioning cooling. As soon as the air conditioners are turned on, the electricity meters spin rapidly. While power grid dispatchers were sweating profusely in the substations, at the Chengdu Shuangliu TeLaiDian charging station, new - energy vehicle owner Zhu Liang (a pseudonym) gently tapped the screen of his mobile phone, and his car began to transmit power back to the 10 - kilovolt power grid: He earned dozens of yuan during the one - hour meal.

This scene is moving from the laboratory to the streets - vehicle - to - grid (V2G) technology has turned electric vehicles into "power bank for the power grid", opening up a new way to make money in the sweltering heat.

I. The Solution of "Vehicle - to - Grid Interaction" under Power Shortage

This summer, the power grid is like a tightly stretched string. A wave of high - temperature warnings has turned half of the weather forecast map in China red.

In Bozhou, Anhui, residential electricity consumption accounts for more than 65%. The concentrated use of air conditioners has sharply widened the peak - valley difference, but there isn't much adjustable load; in Wanzhou, Chongqing, the maximum power grid load has increased by 4.75% year - on - year; in Xi'an, Shaanxi, the power grid predicts that the load this summer will reach 14.8 million kilowatts, with an average annual growth rate of the basic load as high as 7%...

The traditional coping methods are no longer sufficient. State Grid has done its best, putting 140 projects into operation to increase the power supply capacity by more than 30 million kilowatts. However, in the face of load growth in the order of hundreds of millions of kilowatts, new solutions are needed.

Just then, V2G technology appeared at the right time. Electric vehicles have become the "dream cars" of State Grid this summer.

Under the scorching sun, Chengdu car owner Zhu Liang scanned the code to start V2G discharging, and the current was reversely injected into the 10 - kilovolt public grid. "The operation is as simple as charging. Just plug in the gun and scan the code." While having a meal, he earned 48 yuan in revenue - which is equivalent to selling 80% of the battery's capacity (48 kWh) at a price of 1 yuan per kWh. After deducting the charging cost during the nighttime low - peak period, he made a net profit of more than 30 yuan.

The so - called vehicle - to - grid interaction mainly includes intelligent orderly charging and reverse discharging V2G (Vehicle - to - Grid). Through the energy interaction mode, it realizes the two - way energy flow between electric vehicles and the power grid. Electric vehicles can not only charge from the power grid but also transmit power back to the power grid during peak load periods, thus participating in peak - shaving and valley - filling of the power grid, improving energy utilization efficiency, and promoting the consumption of new energy.

Smart electric vehicle owners quickly realized that they could charge their cars during the low - peak electricity period (such as at night) and discharge power back during the peak electricity consumption period in summer (such as when air conditioners are used intensively in the afternoon). This not only reduces the power grid load and contributes to the country but also allows them to "buy low and sell high" to earn the price difference.

Under special circumstances, car owners can earn even more.

For example, in an old community in Shanghai, power shortage affected the cooking and boiling water of 36 households in 3 buildings. Five social new - energy vehicles took turns to supply power to the community temporarily, discharging 260 kWh of electricity in 7 hours, relieving the urgent need of the residents.

As a thank - you, the power supply company gave the power - supplying car owners a 1:1.6 electricity subsidy through the carbon credit system. That is, for every 1 kWh of electricity discharged, they can get credits equivalent to 1.6 kWh of electricity, and these credits can be directly used as cash when charging.

It is precisely because of seeing the social value of reverse discharging that the wave of large - scale implementation has followed. On June 23rd not long ago, 84 charging stations in Shenzhen simultaneously launched a reverse - discharging demonstration, covering multiple scenarios such as creative parks, technology companies, and 4S stores.

In the F518 Creative Park in Shenzhen, YingFeiYuan intelligently linked photovoltaic, energy storage, and V2G: During the peak electricity price period at noon, the system automatically adjusted the discharging subsidy to 2 yuan per kWh to guide vehicles to transmit power to the grid. Smarter car owners have started "charging arbitrage" - charging the battery at 0.4 yuan per kWh late at night and outputting power back at 4 yuan per kWh at noon, making a net profit of 3.6 yuan per kWh.

II. The Technological Confidence of New - Energy Pioneers

The huge driving force brought by policy engines is also boosting this summer's transformation.

Hangzhou introduced the first V2G subsidy policy in Zhejiang on July 1st. During the peak - load period this summer, charging stations participating in V2G discharging will receive a peak - discharging subsidy of up to 2 yuan per kilowatt - hour.

However, when car owners are looking forward to the "discharging economy", skeptical voices have also emerged: Will frequent charging and discharging shorten the battery life?

According to the official statement in Hangzhou - based on the average number of 50 charging times per year for private vehicles and an average service life of 10 years, the total number of charging times for car owners in the whole cycle is about 500 times. However, currently, the designed service life of power batteries is at least 3,000 times. Conservatively calculated based on the actual service life of 2,000 times, each electric vehicle still has more than 1,000 charging times available for vehicle - to - grid interaction in the whole cycle.

In fact, the statement of a 3,000 - cycle service life is outdated. CATL, a battery giant, will launch its "Sodium New" sodium - ion battery in 2025, pushing the cycle life to over 10,000 times, completely rewriting the industry's perception of sodium - ion batteries as "cold - sensitive and short - lived".

This battery can still maintain 90% of its power at an extremely cold temperature of - 40°C through a composite anti - freezing electrolyte and a nano - scale electrode design, and there is no power attenuation at a low 10% power level. This means that even in the cold winter in Heilongjiang, electric vehicles can still stably participate in power grid regulation.

Zeng Yuqun, the chairman of CATL, has also called on car owners at multiple automobile company press conferences to fully charge their cars at night and sell the power when the cars are not in use during the day. In this way, they can not only make money but also do "something interesting".

Mr. Wang, a car owner in Shenzhen, has personally experienced the reliability of the new - generation battery technology. After discharging at the Lianhuashan Super - charging Station for three months, the battery health of his car still shows 100%. Now, it has become a habit for him to plug in and discharge during lunch breaks, just like "depositing money" in the power grid to earn interest.

The ultra - long - life battery technology has removed the concerns about vehicle - to - grid interaction. The battery is like a wallet, and charging and discharging are like depositing and withdrawing money. A good wallet can withstand thousands of openings and closings. Now, battery giants have created a "titanium - alloy wallet".

In addition, NIO, known as the "infrastructure master", has recently been praised by an academician of the Chinese Academy of Engineering for its more than 3,000 battery - swapping stations. Currently, one - third of China's electricity comes from photovoltaic, wind, and hydropower. However, the instability of new energy requires energy - storage equipment, and the "peak - shaving and valley - filling" conversion rate of batteries is 100%. Batteries can store electricity when the power grid has surplus and supply power back when the grid is in short supply. They can also swap batteries for vehicles, achieving three goals at once.

III. A New Energy Ecosystem with Win - Win Results for All Three Parties

The value of vehicle - to - grid interaction is spreading from car owners' wallets to the whole society.

For the power grid, the pressure is turning into a driving force. Among the first nine pilot cities in the country, guiding electric vehicles to act as "mobile power banks" to feed power back to the grid has become an important task for the power supply department this summer.

For example, Hangzhou introduced a subsidy policy, hoping to further verify and promote the regulatory ability of large - scale vehicle - to - grid interaction in promoting the real - time balance of the power system, the consumption of clean energy, and the safe and reliable power supply of the grid, and to provide more useful experience for improving the charging market mechanism and expanding user interaction models.

For users, in the past, they only cared about how fast the cars could be charged. Now, car owners are surprised to find that their electric cars can even earn some pocket money and even achieve zero - cost car use.

Mr. Zhang, a freelancer in Shanghai, drives a rear - wheel - drive Tesla Model Y. Since he occasionally travels to cities such as Hangzhou and Nanjing on business, even though he has a home - charging pile, he sometimes still needs to charge at fast - charging piles outside. The cheapest electricity costs 70 - 80 cents per kWh, and the most expensive he has charged is 2.6 yuan per kWh. So, his monthly electricity bill is about 500 yuan.

If he fully charges his car during the low - peak period when the electricity costs only 30 - 40 cents per kWh and then transmits the power back to the grid during the peak - load period, with a price difference of 1 yuan per kWh. Then, for his 62.5 - kWh battery, if he keeps 20% of the power for personal use, he can still make a net profit of 50 yuan each time. This means that he only needs to discharge 10 times a month to use the car at zero cost.

However, such operations are based on the premise that car owners have time. After all, the coverage rate of charging piles supporting the V2G function is currently low, and car owners need to spend time going to the designated charging piles to complete the discharging. But with the advancement of policies and the popularization of technology, the number of charging piles supporting this function will surely increase significantly. When home - charging piles can also charge power back, consumers can plug in the charging pile after getting home from work, set it to charge power back to the grid during the peak - electricity period, and let the battery charge automatically when the electricity price is low in the second half of the night. They can then set off with a fully - charged battery in the morning, which is both convenient and profitable.

For the whole society, there is a new path for low - carbon transformation. State Grid transmits hydropower from the southwest and wind and solar power from the northwest across regions through ultra - high - voltage channels. This summer, the cross - provincial power transmission exceeded 200 million kilowatts. When electric vehicle clusters act as distributed energy storage, the intermittent problem of wind and solar power can be easily solved. Vehicle - to - grid interaction enhances the resilience of the power grid and, more importantly, promotes the consumption of clean energy.

With the implementation of the new 2 - yuan - per - kWh subsidy policy in Hangzhou and the launch of CATL's sodium - ion battery production line, vehicle - to - grid interaction is moving from technological experimentation to large - scale profitability. When millions of electric vehicles charge and discharge in an orderly manner under the dispatching of the power grid, individual benefits and system safety have never been so unified.

At the Shenkang charging station of Shenzhen Bus Group, more than a dozen pure - electric buses are quietly connected to the V2G charging piles. They discharge power collectively during the peak - load period of the power grid, with each bus outputting 150 kWh of electricity each time, and are taking turns to achieve the daily discharging target of 15,000 kWh. These steel giants that used to simply consume electricity are now reconstructing the energy logic with the "discharging economy".

As Zhu Liang, the Chengdu car owner mentioned at the beginning, said: "Now, parking and charging is like opening an account in the bank. What you deposit is electricity, and what you get out is money." This quiet energy revolution is making each electric vehicle a capillary of the smart grid, writing a new money - making script in the era of carbon neutrality through the "buy - low - sell - high" electricity flow.

This article is from the WeChat official account "New Energy Outlook", author: YouJian Editorial Department, published by 36Kr with authorization.