Electric vehicle owners might never have imagined that after enjoying benefits like cheap charging， waived purchase taxes， and exemption from traffic restrictions， they could even earn money by selling the electricity stored in their vehicles.
Recently， Vehicle-to-Grid (V2G)， a term that seemed to have faded from common discussion， has reappeared with renewed vigor.
Mid-month， Tianjin announced it would launch a “Vehicle-Grid Interaction Demonstration Month” in September and October， aiming to explore new forms of V2G. Two days later， Guangzhou released its “Work Plan for Building a National Scale Pilot City for Vehicle-Grid Interaction，” outlining efforts to promote the large-scale application of V2G.
Coincidentally， around the same time， BMW announced in Germany its collaboration with a company called E.ON to launch Germany’s first V2G solution for car owners， which will be supported by the newly released BMW iX3.
This surge of activity suggests a burgeoning V2G trend both domestically and internationally.
If you haven’t encountered V2G before， it’s quite straightforward. V2G stands for Vehicle-to-Grid， referring to the capability of new energy vehicles to send electricity back to the power grid.
With this functionality， EV owners can profit by buying electricity when it’s cheap and selling it back when it’s expensive.
As is widely known， electricity prices， whether for commercial or residential use， are segmented into peak and off-peak (valley) rates， with peak electricity being significantly more expensive， sometimes by a factor of two or even more.
Therefore， much like a supermarket buying and selling goods， EV owners can charge their vehicles during low-price periods and then sell the electricity back to the grid via V2G when prices are high， pocketing the difference.
And the earnings can be substantial.
Taking the V2G pilot programs in Guangzhou and Shenzhen earlier this year as an example， the valley electricity rate for residential use in Shenzhen was 0.4 yuan per kWh， while the grid’s purchasing price from vehicles reached nearly 1 yuan per kWh at its peak. Combined with subsidies provided by the grid for the pilot program， owners could receive 4 yuan per kWh for the electricity they sold， directly earning a profit of 3.6 yuan.
With sufficiently high discharge power， this translates into significant earnings. One blogger on a platform noted earning 120 yuan in just half an hour of discharge， with profit margins and speed comparable to highly lucrative ventures.
Even the BMW and E.ON collaboration mentioned earlier highlighted the potential annual earnings for car owners (approximately 720 Euros， or 6002 RMB) as an incentive.
So， why would the power grid encourage， or even subsidize， people selling electricity， seemingly at a loss?
This brings us to the potential “peak shaving and valley filling” (load balancing) function behind V2G.
While China’s power grid infrastructure is world-class， it still faces challenges during national peak electricity demand.
For instance， during the summer peak electricity demand in 2023， the national peak load reached 1.37 billion kilowatts. However， the total installed generation capacity from all sources was only 2.6 billion kilowatts， with 40% coming from less stable sources like wind and solar power.
Consequently， during peak demand， the grid is forced to either ramp up generation significantly or implement power rationing， impacting daily life to manage demand， placing immense pressure on the system.
Conversely， during off-peak hours， when electricity consumption is low， power generation methods like hydroelectric dams continue to operate. Unused electricity is essentially wasted.
Considering the proliferation of new energy vehicles on the roads， they represent a perfect solution for storing this wasted electricity and alleviating grid pressure during peak times – effectively achieving peak shaving and valley filling.
With over 36 million new energy vehicles in China， theoretically， if each vehicle has a 10kW bidirectional charging capability， it could collectively provide nearly 400 million kilowatts of power， accounting for about one-third of the national peak load.
These EVs are essentially decentralized power sources!
If they can be effectively utilized during peak demand， it would significantly ease the grid’s supply pressure. Furthermore， it would encourage charging during off-peak hours and selling the otherwise wasted electricity， creating a win-win situation.
This is precisely why V2G has experienced a resurgence after years of quietude. The rapid growth of new energy vehicles in China over the past year or two has transformed “peak shaving and valley filling” from a theoretical concept into a seemingly achievable reality.
I understand that upon reading this， some readers might already be searching for nearby V2G charging stations， eager to “bankrupt” the State Grid by selling them electricity.
However， upon checking charging station maps， you’ll likely find that while the idea is appealing， the reality is quite different.
The number of charging stations supporting the “selling electricity” functionality that are accessible to the public is currently very limited. Many cities， even major metropolises， lack even a single V2G-compatible charging station.
Why is this the case? Isn’t V2G supposed to be so beneficial?
The challenges and obstacles to widespread V2G adoption are considerable， much like the slow rollout of ultra-fast charging stations in the past. It will likely take some time before profiting from selling electricity becomes a common reality.
These challenges involve the vehicles themselves， the charging infrastructure， and the power grid， all of which contribute to high costs and complexity.
From the perspective of electric vehicles， to sell electricity back to the grid， vehicles must be equipped with a bidirectional On-Board Charger (OBC) and possess a significant outward discharge capability.
However， a bidirectional OBC can cost 20-30% more than a unidirectional one， adding at least a thousand yuan to the vehicle’s cost. Not all automakers are willing to bear this additional expense.
Even when equipped， standardizing bidirectional charging protocols remains a significant hurdle. Currently， China’s only recommended standard for vehicle charging interfaces is GB/T 20234， leading to a multitude of proprietary charging protocols among different vehicle manufacturers and charging station providers. This means simply plugging into a V2G charging station doesn’t guarantee compatibility.
The current solution is a rudimentary and inefficient one: collaboration between companies. Previously， Nio， for example， had to sign agreements with State Grid Southern Power Company and negotiate with CATL to enable limited V2G pilots for its owners.
It will likely take considerable time before a unified protocol is established for vehicle manufacturers， power grids， and charging infrastructure providers.
Of course， cost and protocol issues， while challenging， are somewhat manageable. The true difficulty and time commitment lie in how the power grid can effectively leverage V2G.
While V2G offers the benefit of peak shaving and valley filling， it comes with its own set of considerations.
For instance， when a large number of vehicles simultaneously feed power back to the grid， it can inject undesirable harmonics into the distribution network and cause temporary voltage fluctuations.
This could increase the wear and tear on grid equipment like transformers， reducing their lifespan. Furthermore， the fault protection mechanisms in traditional grid infrastructure are largely designed for one-way power flow.
In the event of a short circuit during large-scale V2G deployment， if not managed properly， it might become difficult to locate and isolate the fault， potentially leading to widespread power outages.
Therefore， to accommodate widespread V2G adoption， distribution networks require significant upgrades， including the implementation of better inverters， more intelligent dispatch systems， and even the modernization of regional distribution networks. These represent substantial engineering and technical challenges.
This is why the V2G tests mentioned earlier in various cities are limited in scope and duration – they are essentially stress tests for the distribution grid.
Moreover， similar to the initial rollout of ultra-fast charging stations， the cost of V2G-enabled charging stations is 2-3 times higher than that of ordinary fast-charging stations， making widespread V2G integration a systemic endeavor requiring adaptation from vehicle manufacturers， grid upgrades， and substantial infrastructure investment.
However， as a nation known for its infrastructure prowess， China has a track record of tackling challenging projects.
As of August this year， a total of 13 provinces and cities have introduced policies and subsidies related to V2G， covering everything from private vehicles and ride-hailing cars to commercial vehicles like heavy-duty trucks， demonstrating a strong commitment to making V2G a nationwide initiative.
Therefore， I anticipate an increasing number of small-scale pilot programs， similar to those mentioned at the beginning， will become more common， with extended durations and wider city coverage.
Nio and Tesla owners who are currently enjoying lifetime free wireless charging and battery swapping services might want to explore the potential of V2G.
