V2G (Vehicle to Grid)

Vehicle-to-Grid (V2G) technology enables battery electric vehicles (BEV) to send energy back to the electricity grid via a bidirectional charger controlled by a remote management system. V2G differs from the simpler Vehicle-to-Home (V2H) and Vehicle-to-Load (V2L) technologies, which only allow vehicles to power homes or connected electrical devices, but not to send energy back to the grid.

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How V2G Works:

Battery electric vehicles (BEV) are equipped with a traction high-voltage battery, the capacity of which usually equals the several-day consumption of a family house (e.g., Škoda Enyaq iV 80: 82 kWh, Volkswagen ID.3 Pro: 58 kWh, Hyundai Kona electric: 64 kWh, Tesla Model 3 Long Range: 82 kWh). The main problem is that this energy is stored in the battery in the form of direct current (DC) voltage, usually 400 V or, in newer electric vehicles, 800 V. However, common household appliances operate on alternating current (AC) voltage of 230 V (120 V).

V2G technology uses controlled bidirectional energy converters (V2G UNIT), which allow electric vehicles to either charge their batteries or, conversely, send energy back to the grid, thereby helping to stabilize the grid, especially during times of high electricity consumption.

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To better understand the benefits and potential of V2G technology, let’s describe a typical model example:

A study by the European Environment Agency (EEA) anticipates a significant development of electromobility and predicts that by 2050, up to 80% of passenger cars in the EU will be powered exclusively by electric drive. Let’s leave aside whether this is the right path and whether it was established democratically or through political pressure. Everyone must answer these questions for themselves. The transition to electromobility will primarily bring new technical possibilities for electric vehicle users and major challenges for the energy infrastructure.

It is clear that the approach to managing and storing electricity will change significantly in the future. One of the main problems with using electricity is its difficult storage. For small consumers and motorists, a battery usually serves as an electricity storage device, which is, however, relatively expensive, heavy, and has a relatively low energy density. However, if there are batteries in thousands of vehicles, why not use them for something other than just propulsion? They could serve as temporary energy storage – mobile battery storage units that could help stabilize the electricity grid.

Vehicle-to-Grid (V2G) technology offers a potential solution to this idea. V2G allows the use of energy stored in the batteries of electric vehicles and returning it to the electricity grid during peak demand. This technology can help balance fluctuations in electricity production from renewable sources. Ultimately, V2G can bring benefits to both electric vehicle owners and society as a whole.

Unfortunately, the use of V2G requires the cooperation of governments, electricity suppliers, and car manufacturers, which significantly complicates its development. Three basic conditions must be met for the V2G service to function:

• the electric vehicle must have a V2G function
• a compatible bidirectional charger
• the owner must join a virtual power plant program

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Practical Use of V2G:

• the average battery electric vehicle has a battery capacity of 60 kWh, which is six times more than a typical home solar battery with a capacity of 10 kWh and approximately three times more energy than the average household consumes per day
• the problem is that the energy is stored in the form of direct current voltage in the vehicle’s traction battery
• electricity generated from renewable sources has fluctuating power output
• the vehicle is parked most of the time

If you combine the above facts – which, of course, are not universally applicable – as a case study, V2G technology emerges as a very interesting alternative.

However, connecting electric vehicles to the electricity grid using Vehicle-to-Grid (V2G) technology presents both technical and administrative challenges. Firstly, transferring electrical energy to the public grid requires a thorough technical solution with an emphasis on the safety and reliability of the connection. Secondly, it involves a bidirectional connection to the public electricity grid, which requires compliance with many different relevant regulations and standards, often regional.

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Advantages of V2G:

• stabilization of the electricity grid – V2G allows electric vehicles to send energy back to the grid, which helps to balance the supply and demand for energy, especially during peak times
• flexibility of energy use – V2G enables the use of accumulated energy in electric vehicles to support local electricity grids and reduces the need for expensive investments in new infrastructure
• financial benefits for electric vehicle owners – electric vehicle owners can receive financial rewards for supplying energy to the grid during high consumption
• support for renewable sources – V2G can help with the integration of irregular energy supplies from renewable sources and promote their wider use

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Is V2L very different from V2G?

People often confuse V2L (Vehicle-to-Load) technology with V2G (Vehicle-to-Grid) bidirectional charging. They are not the same – these technologies are used for two completely different purposes. V2L is much simpler and allows powering any common household appliance from an electric vehicle using an extension cord. Conversely, V2G is much more complex and can supply energy back to the electricity grid (or home circuits) using an external bidirectional charger.

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