General Motors and Pacific Gas and Electric are collaborating to determine how electric vehicles can be used to power people's homes during power outages and even feed electricity back into the grid during periods of peak demand. The pilot will take place in California, home to PG&E, where wildfires are straining the state's energy infrastructure.
A new automaker between General Motors and Pacific Gas & Electric, the partnership revolves around "vehicle-to-grid" technology (PG&E has a similar project with BMW). The idea of this technology is to use a bidirectional charging device that is capable of charging or transferring power from an electric vehicle out at any given time. Essentially, it sees high-capacity batteries not only as power tools for electric vehicles, but also as backup batteries for the grid.
Rick Spina, GM's vice president for electric vehicle commercialization, said the company expects to have 1 million electric-vehicle production in North America by 2025. Unlike other automakers, as of now, GM has not released an electric vehicle with an "on-board load" feature. But Spiner said GM plans to make up for the missing feature with an over-the-air software update soon.
"We're on the cusp of turning electric vehicles into a power source for customers," Spiner said. "These customers don't even realize it."
This summer, GM will test two-way charging technology, as well as a "software-defined communication protocol," at its PG&E lab in northern California. Under the agreement, in the event of a power outage, the recharged EVs are able to automatically deliver electricity to their homes. Going forward, GM and PG&E plan to select a select group of customers in California to test the two-way charging technology in their own homes, aiming to roll out broader customer trials by the end of this year.
"Imagine a future in which every garage has an electric car that acts as a backup power source when needed," Spiner said.
In fact, there are still many things to be determined, such as how will GM convert the power of the electric vehicle battery from DC to AC? Spiner said GM has not yet determined whether the conversion process will take place in the car itself or through another device, such as a wall charger.
Spiner believes that the potential of bidirectional charging technology lies in the transition from polluting gas-fired power generation to a cleaner and more efficient way of generating electricity. The average California home uses about 20 kWh of electricity a day, while the Chevrolet Bolt has a 60 kWh battery, Spiner said. That means the conversion can supply at least two or three days' worth of electricity for a family, he said.
Relieve grid strain with a flood of electric vehicles
Large numbers of electric vehicles can also be used to relieve grid pressure during peak demand periods, such as summer. In these cases, Spiner said, some payment could be made to give back to EV owners who feed electricity back into the grid.
PG&E, based in San Francisco, is serving a pilot for two-way charging technology. The region already has more than 320,000 electric vehicles. Vehicles in the region account for roughly 20 percent of all electric vehicles in the U.S., according to PG&E. By 2030, California is expected to have 5 million electric vehicles on the road. Last year, California became the first state to ban future sales of internal combustion engines.
If enough EVs are plugged into the grid, they could become sizable "virtual grids." They're just a network of connected batteries that can be called together when the power company needs more power. In addition, connected home solar power systems can serve the same purpose. We hope that by working together, these batteries can relieve the strain on the grid during times of peak demand. A virtual grid could also replace the polluting, fossil-fuel-fueled "peaker plants" that power companies have always relied on in times of energy shortages.
Two difficulties are difficult to overcome
Seemingly advanced virtual grids are nothing new. In the Chinese market, the exploration of this business model has already begun. In September last year, at the 2021 World New Energy Vehicle Conference, Xin Baoan, chairman of State Grid, said that if V2G technology can be widely used in the future, and pure electric vehicles can be sent back to the State Grid, then the State Grid will have Huge potential for dispatchable energy storage. And as early as 2020, State Grid is already experimenting with this.
According to the data of State Grid, by November 2020, State Grid had carried out nearly 40 pilot projects in 14 provinces and cities across the country, and deployed nearly 400 V2G charging and discharging terminals. Users can participate in V2G through the "e-charging" APP, and perform intelligent charging and discharging regulation according to the needs of the power grid, and can obtain real-time benefits. According to estimates, the power battery power of 300 million electric vehicles in the future can reach more than 20 billion kWh, which can provide 12 billion kWh of energy storage for the grid.
Of course, this also has certain benefits for users. Last year, University of Delaware professor Willett Kempton announced the results of his research on the problem of reverse current transfer from vehicle to grid (Vehicle to Grid, V2G). Kempton completed the prototype of the entire operating system in 2021. The system uses 15 Mini Coopers and lets them just send some electricity back to the grid at the right time. The value obtained is $5 a day, which is about 30 yuan.
In addition to buying electricity at the troughs and selling electricity at the peaks to earn the price difference, the power grid also requires a balance of supply and demand. In order to ensure the stability of the power frequency, the power grid needs to have many thermal generators, which are switched on and off to maintain the stability of the power frequency. But such generators are slow to start, inefficient, and polluting the environment. The reason is the same as the sudden braking or sudden start of a car. But all the costs it causes will eventually be billed to the electricity user. But it would be a cleaner, faster, more efficient, and less expensive way to switch to an electric vehicle for charging.
In fact, some charging and swapping companies also use reverse charging as one of the profit models. Zhu Gongshan, chairman of GCL Nengke, previously stated that every electric vehicle is a mobile energy storage station in its view, which enables it to store surplus electricity and sell it at peak times, greatly expanding the power supply of electricity and energy. Adjustment ability. However, even energy and car companies have a lot of aspirations for this model, but it is actually very difficult to achieve this goal.
As far as V2G is concerned, there are still many immature places. For example, in order for the car to have the ability to supply power back to the grid, the electric car must have a two-way charger, but it is generally not available today. Moreover, the bidirectionally transmitted current will always be converted between AC (alternating current) and DC (direct current), causing a lot of losses and affecting the charging efficiency. Some research institutes believe that there are two prerequisites to achieve V2G: 1. Integrate a two-way charger; 2. Have a charging system and mechanism to tell the owner when to charge and when to discharge.
As far as the second point is concerned, some places have already implemented V1G, which is mainly to install a set of intelligent driving control system in the car. He can complete the charging by controlling the time during charging, such as choosing when the price of electricity is high. Not charging, but charging at night when electricity prices are low. But the problem with such a system is whether it can guarantee charging overnight. V1G is regarded as a transitional solution to V2G. But for most people, they don't see profit from V2G.
Some people have calculated that if reverse charging is performed on an electric vehicle with 75 kWh of electricity, the income per day will be between 30-50 yuan, but the question is, are you willing to use the vehicle as an energy storage station and let the battery withstand this income Double the number of charge and discharge?
Of course, for the swap station, it has the potential to become a virtual grid. But on the whole, there is no mature business model and a feasible solution after calculation. The additional benefit of V2G in terms of stabilizing grid frequency will eventually be distributed to millions of EV owners. Moreover, if the scale of electric vehicles continues to increase, the actual profit of subsequent owners will become less and less. In this case, the economic value of the technology's existence will become lower and lower? In contrast, the value of the power station may be greater.
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