Vehicle To Grid (V2G) technology offers the potential of utilizing an unused asset (a parked electric car battery) and turning it into a new revenue stream for the owner.
This helps alleviate the cost of ownership following the high initial purchase price of EVs. The technology is being trailed in various locations worldwide and is showing promise.
1️⃣ V2G systems reverse the flow of electricity back into the grid to help out when supplies are constrained.
2️⃣ It would require users to purchase two-way (bi-directional) chargers to reverse the current flow while also converting it from DC to AC.
3️⃣ By 2030, the number of electric vehicles charging on the grid will place severe strain on existing infrastructure.
4️⃣ One of the biggest factors preventing widescale adoption is the increased wear on the EV battery, with the number of charging cycles growing.
What Is Vehicle-To-Grid Technology?
The theoretical benefits of V2G systems are compelling, and if the technology ever achieves wide-scale acceptance, it will redefine how electric power is generated in the future.
V2G systems enable an electric car’s battery to be used to add power to the utility grid for energy storage when it is not being used.
How V2G works
There are two levels of vehicle-to-grid technology (V1G and V2G).
V1G is already in extensive use by electric car and EV charging manufacturers already.
V1G enables the charger, or car, to be programmed to only charge outside of peak cost electrical periods.
This means that the charge consumed by the electric vehicles can be balanced on the grid, helping the grid to remove the peaks and dips from the general consumption.
V2G is the next logical step in the chain. With V1G systems, once the car is charged, it is unplugged and removed from the system.
Car’s or chargers’ systems equipped with the V2G system are able to communicate with the grid and implement the following actions:
1️⃣ If the grid is approaching overcapacity, the charge rate can be slowed down or paused.
2️⃣ If the battery is sufficiently charged, it could then offer some of its charge back to the system to reduce the strain on the grid.
V2G systems can work at the local building level or at the local grid level.
At the building level, if the consumption at the property exceeds a certain value, the building would be able to log into the EV that is being charged and reverse the electrical flow to use it for the building’s benefit.
The same principle would apply to the local grid. This type of system is already in place in many states who offer net metering schemes to households.
These systems offer a rebate or dollar value benefit back to homeowners with solar systems for power fed back into the grid.
Equipment And Infrastructure Required For V2G
The system needed to run a V2G system already exists at the utility companies’ level. The equipment is already able to use excess solar-generated electricity from households with a surplus available.
The electrical vehicle chargers would simply become another source of energy to be registered on the system.
The most significant change will occur at the consumer level. The EVSE (Electric Vehicle Supply Equipment) will need to be modified from unidirectional to bi-directional devices that include DC to AC inverters within the equipment.
The effect of this is that the current devices, which can only process the flow of energy from AC to DC (although some cars have AC batteries) in one direction, will have to be modified to enable a reverse flow.
These devices will also have to accept the DC current from the car’s battery (where applicable), pass it through an inverter (convert it to AC), and then deliver it back into the grid.
The device will also require a communication protocol (possibly internet based) where it can connect to the utility’s grid and accept requests for the following:
- To enable the car to be charged
- To notify the grid regarding the car’s state of charge
- Reduce the charging speed if requested by the grid.
- To stop charging if the grid is under pressure.
- To reverse the flow of current back into the grid if requested.
Process Of Sending Power From A Vehicle To The Grid
Any power transferred to the grid from an electric vehicle must never be at the expense of the range required in the electric car by the driver.
Despite this, battery charge which is not going to be used is a waste. And there is no point in holding into excess charge when it is not required.
Once the EV battery is full, the car may be able to sacrifice 10 – 15% based on the driving distance to the next charge.
Because of this, complex software will have to be included in the electric vehicle systems or EV battery chargers.
The software will communicate to the utility’s main load control system, which will notify the network of cars when it requires energy.
Cars that have the capacity will reverse the flow of the charger back into the inverter, which will convert it back to AC and feed it into the system.
The electrical meter will have to be a smart device that records the different flows of energy and notifies the utility billing system of the power transferred each way.
Types Of V2G Systems
As discussed earlier, V1G (first generation) systems are actively used in several electric cars and charging station manufacturers.
These use a unidirectional charger which will only carry current from the power grid through the charger or the car.
The more advanced systems are able to communicate with the grid and adjust the charge rate based on information received from the utility.
- If the utility is becoming capacity-strained, the car charger can be requested to stop smart charging.
- If the utility is being heavily utilized but still has the capacity, it can request the charger to reduce the amperage used by the system until the demand reduces.
- If excess capacity is available, the utility can instruct the charger to increase the rate of charge.
The V2G systems have all of these capabilities. But they are also bi-directional chargers, and if the utility capacity is exceeded, its systems can request the EV chargers to reverse the flow and push power back into the grid.
The Background To V2G Systems
The electricity consumption available in America at any point in time is 1.2 million megawatts.
The fuels used to generate the capacity are listed below.
|Nameplate Capacity (MW)
In October 2022, it was estimated that there are 1.7 million electric cars on the road in the US, and it is projected that this will increase to 26.4 million in 2030.
Based on an average EV battery size of 92 kilowatts, if all the electric vehicles were to plug in simultaneously and start to charge, they would require the following power supply from the grid.
|Number of EVs
|Total Battery capacity
|Hourly charge rate over five hours
|Percentage of US grid capacity
The table shows the amount of charge electric vehicles would require to simultaneously charge in 2023, compared to 2030.
In 2023 it is a negligible 2.52% of the grid capacity. However, if the projected growth in EVs occurs by 2030, almost 40% of the grid would be used if all EVs were plugged in simultaneously.
While every EV in the country being charged simultaneously is not a realistic situation, it demonstrates the scale of the burden which could be placed on an already constrained national energy supply.
The position will be exacerbated because of the pressure to convert the current 779,698 megawatts (62.40% of the total) generated by carbon-emitting nonrenewable fuels.
There are three solutions that federal and state authorities are considering, and which ultimately will be implemented together to a greater or lesser degree.
1️⃣ Convert the US electrical generation to renewable technologies.
2️⃣ Partially democratize electrical generation.
3️⃣ Implement Vehicle-To-Grid Systems.
Convert The US Electrical Generation To Renewable Technologies
A study conducted in 2019 calculated that it would cost $4.5 trillion to eliminate power stations that run on non-renewable forms of energy and to convert the whole US electrical generation fleet of power stations to renewable fuels.
This amount represents 20% of the US Gross domestic product (GDP) and is essentially unaffordable in a single exercise.
Even if the grid can be converted to renewable sources, the current generation is very fickle and unreliable.
Solar does not produce current at night or in overcast weather, while wind turbines stop working if there is no wind.
To mitigate against this, the country will have to have a backup power supply when the situation demands it.
V2G may be the backup solution required.
Partially Democratize Electrical Generation
The federal government and most states already heavily subsidize households and businesses to move away (either fully or partially) from the utility grid.
By including a net metering scheme for solar-equipped households, any excess electricity that they generate can be fed back to the grid, and the household can be remunerated.
Implement Vehicle To Grid Systems
V2G systems are designed to use an electric car battery to feed into the national electrical grid.
Assuming that there are 26.4 million electric vehicles on American roads by 2030, the potential battery capacity available for use by the grid would be 2.4 million megawatts.
This value is twice the size of the current power supplied by the grid.
This may seem unrealistic, but apart from peak commuting periods, it is estimated that 95% of all cars are parked simultaneously. To put it another way, only 5% of cars are using their batteries for the purpose they were intended – to power the car.
V2G proposes that the battery power of these cars be harnessed when not in use.
The Impact Of V2G On The Grid
The potential impact on electrical generation utilities is potentially profound.
Help To Balance The Grid
In the past electrical power stations were sized to provide energy irrespective of what the demand was.
Having the capacity to generate electricity when the demand does not exist is a waste of resources.
Similarly, not having sufficient capacity when demand is high is just as serious and can ultimately impact our country’s financial prosperity.
By having a constant reserve supply of available power, V2G and other dispersed power supply systems (such as private solar plants) can reduce the need for power stations to be sized for the maximum possible demands.
This is particularly important with states moving to renewable energy sources and which have already committed to massive capital investments.
Reduce The Need For Peaker Power Plants
Peaker power plants, also known as Peaking Power Plants, are built to provide energy only when the main grid production is constrained or exceeds a specific value.
When not in use, they represent wasted capital that could be used for more effective purposes.
V2G systems may be the solution to this problem.
V2G And Electric Vehicles
Even the most dedicated petrolhead sees the light in the door, the number of vehicles using internal combustion or diesel units (compression) is diminishing, and EV production is increasing.
Potential For V2G To Increase EV Adoption
It is estimated that by the end of 2022, there were 1.7 million EVs running on American roads. This is projected to increase to 26.4 million cars by 2030.
This may seem a lot, but it will still only represent 9% of the 290.8 million cars which were on American roads at the end of 2022.
There are many reasons why the switch to electric has not been as fast as ecologists would like, some of which are listed below.
1️⃣ EVs are still substantially more expensive than gas-powered equivalents.
2️⃣ Gas is still relatively cheap, and the economics of driving a gas-powered car still make sense.
3️⃣ There is an impression that battery technology will increase massively in the next few years, which may render old systems obsolete.
4️⃣ Gas-powered cars still have a big emotional following.
5️⃣ Politics plays a part where different parties take opposing views.
V2G could be a big driver in changing the economics of EVs. While combustion cars will always involve an ongoing gas cost, EVs that subscribe to a V2G system could become revenue earners for their owners.
Economic Benefits Of V2G For EV Owners
The revenue benefits have not yet been calculated because the federal and state governments are still considering whether to adopt the scheme.
The principal will be that the customer will be remunerated for each unit of power that is fed back into the system.
In addition, we would imagine that there will be a form of subsidy or tax rebate scheme to persuade EV owners to convert to a bidirectional charger.
Challenges and Future Developments
The concept is either in the development or trial phase in many countries.
Challenges Facing The Widespread Implementation Of V2G Systems
There are several challenges that may prevent a widescale adoption of V2G.
1️⃣ The increase in charge and discharge cycles will shorten the EV battery’s life expectancy. This is not covered under the vehicle warranty, so a Federal or state system of compensation will be needed.
2️⃣ If the car is used a charged across multiple utility boundaries, it will require very sophisticated software to stay in communication with the system and to credit the correct utility account.
3️⃣ For various reasons, several car manufacturers will not adopt it because it competes with existing off-grid power systems they offer or fear of increased wear on the battery.
Research And Development Efforts In The Field Of V2G
The technology to make V2G viable exists and is in place. There are several trials being operated in countries worldwide, and the data needs to be analyzed to be assessed.
Future Growth Of The V2G Market
The V2G market growth will depend on two primary factors.
- The results of the trials currently being conducted.
- A way to manage the increased wear on EV batteries due to the increase in charging-discharging cycles
What Cars Can Do V2G?
The only electric cars equipped to connect to a V2G network are listed below.
- Nissan e-NV200
- Nissan LEAF
- Mitsubishi Outlander PHEV
- Mitsubishi Eclipse Cross PHEV
- All Volkswagens using the MEB (modular electric-drive toolkit) are sold with V2G capability.
- Ford F150 Lightning
Will Tesla Do Vehicle To Grid?
Tesla has spoken against V2G systems. It appears that they have two reasons behind their resistance:
1️⃣ The system effectively completes with the Tesla Powerwall.
2️⃣ The electric vehicle batteries, which are one of the most expensive components, will degrade faster and have a shorter life expectancy.
In summary, this is a thorough introduction for you to sink your teeth into, and the main takeaways to remember are:
1️⃣ If there are 26.4 million electric vehicles being driven in the United States by the year 2030, then it would be possible to use the battery capacity of these vehicles to provide up to 2.4 million megawatts of power to the grid.
2️⃣ V2G offers the potential for the vehicle owner to turn a stagnant asset into one that will minimize the cost of ownership relative to its gas-powered equivalent.
These are the potential major benefits of the technology if (and it’s a big if) it can pass all the technical hurdles before widespread adoption.