What Is Bidirectional Charging?

Bidirectional charging is an exciting technology that allows charging of an EV and the distribution of charge back to the grid to balance the demand by taking power stored in the EV battery and pushing it back into the grid.

At a Glance:
1️⃣ Bidirectional charging is dependent on smart charging capability.

2️⃣ Vehicle-to-grid or V2G is required for bidirectional charging.

3️⃣ It can be used to operate the electric car motor (AC) or as battery energy storage as Direct Current.

Now let’s dive into the subject further, starting with how it works. 

How Bidirectional Charging Works 

Bidirectional charging, or Vehicle-to-Grid as it’s more commonly known, works by allowing the EV battery to provide power to the grid, another electric vehicle, or your home in a power outage. These concepts are commonly known as V2G and V2H, respectively.

This is done as the smart technology involved; the charging device can absorb the charge stored in a battery and send it back to the grid when needed.

Using different energy signals, the car can be charged or discharged based on whether energy is produced or required. So, when the battery is flat, it can recover the charge by initiating the cycle.

Where the battery is charged, and the grid, building, or another EV requires a charge, V2G can deliver a charge as needed.

Consider bidirectional charging as having your EV act like a mobile power bank, just like the small ones you use for your phone. So first, you charge the battery, and then you can use it to charge your phone or someone else’s – this is bidirectional charging in action.

Different types of bidirectional charging exist, such as V2G (vehicle-to-grid), V2H (vehicle-to-home), and V2L (vehicle-to-load), which is the most common type.

Here, the EV needs to have a built-in converter and 120V plugs that can be used to power appliances, tools, and other devices.

Smart Charging Vs. Bidirectional Charging 

First off, these are not the same. With V2G, you need smart charging capacity as you require the cloud connection between the charging operator, the EV, and the charging device. 

Smart charging is purely the technology that utilizes intelligence to determine when and how the EV is charged based on grid demand and low-tariff charging times, as well as using apps through Bluetooth or WiFi to manage the charging process.

While the two are different, bidirectional charging requires smart charging integration to facilitate the supply of stored power back to the grid, building, or another vehicle.

Advantages Of Bidirectional Charging 

There are three major advantages:

  • You create a portable and powerful power source.
  • You save money on energy usage.
  • Improved grid flexibility and reliability.

Let’s expand on each of these a bit more.

Bidirectional Charging Provides A Powerful Portable Power Source

An example is going on a camping trip and charging your EV at home before departure or on the road before arrival.

You could use the energy stored in the EV to supply power at the campsite or even help someone else charge their EV.

The 120V outlet is the same as the regular ones you find in your home, and you can use that energy to drive lights, mobile chargers, and laptops the same as you would at home, without the need to cart a generator or inverter around with you.

You Cut Your Energy Usage Costs Using Bidirectional Charging

An average home would use around 30kWh per day, while an average EV car battery can hold about 60kWh, so you could power your home using an EV battery instead of the grid.

How does this save you money?

By charging your EV overnight when the tariffs are much lower than during peak demand hours and then using that power to run your home, you effectively use much cheaper electricity than you usually would.

This concept has driven a Californian company called Proterra to create an EV with a 660kWh battery designed to keep the power on at shelters and response centers during natural disasters.

Not only can you save money, but you can make money using bidirectional charging as well. As you would do from feeding power back into the grid from your PV system where excess energy is stored, you can do the same using your EV.

Furthermore, if you can use your home PV system to charge your EV battery and then use that to power your home or business, you are effectively getting free power!

Bidirectional Charging Offers Improved Grid Reliability And Flexibility 

Having a bidirectional EV that can deliver charge back to the grid when and where needed means the grid becomes more stable and reliable as external sources feed power back into the grid and reduce production demand and congestion. 

Making additional energy available across the country through bidirectional charging lowers the cost of power as producers don’t have t buy energy at higher prices from third-party suppliers. Plus, it allows for the deployment of USEF or the Universal Smart Energy Framework.

Bidirectional EV charging provides for the implementation of smart energy grids and the management of consistent supply standards.

By 2030, there will be around 140 million – 240 million EVs on the planet, which would mean an aggregated power capacity of about 7 TWh or seven trillion watt hours or enough energy to power 200 000 homes!

Application Of Bidirectional Charging 

Bidirectional charging for EVs can have one EV charging another, whether at home or helping someone who has run out of power with enough charge to reach a recharging station.

Where your EV has a larger battery, you can use it to charge smaller EV batteries while still having enough power to get back home or back to your office or charging station.

Bidirectional Charging Creates A Backup Power Source For Your Home Or Business

Tied into the money-saving benefit, bidirectional technology allows you to create a backup power source for your home or business.

Charging your EV overnight using lower tariffs and then utilizing the battery to run your business or home when the grid is down can keep you running when everyone else is in the dark. This removes reliance on the grid, and you save money by effectively powering your home with cheaper electricity.

If you use your EV at home with your PV system to power your business, you have eliminated your energy costs!

Challenges And Barriers To The Widespread Adoption Of Bidirectional Charging 

There is no doubt that the future is bidirectional charging, but several major challenges require resolution before that can become a reality.

The issue of standardized charging protocols and connectors has to be resolved so that all EVs can utilize bidirectional charging. For example, while some EV manufacturers like Ford only have connectors that work with other Fords, Nissan uses universal bidirectional chargers.

Another consideration is whether the V2G/V2X/V2B/V2H charging will considerably reduce battery lifespan, which could increase the costs to the consumer in terms of maintenance.

At the same time, they would not see any significant revenue from the electricity they supply back to the grid.

A third issue is integrating the infrastructure to facilitate large-scale bidirectional charging and feedback into the national grid. Many countries are only in trial mode, seeking optimal solutions before implementation.

In short, the infrastructure and charging protocols need to be regulated and formulated, and consumer incentives improved to compensate for the costs of acquiring bidirectional charging technology, as they are more expensive than standard Level 2 chargers.

Key Takeaways 

1️⃣ Bidirectional charging offers grid stabilization and recharging from millions of EVs, lowering grid demand. In addition, it reduces operating downtime when the grid is offline

2️⃣ Using a vehicle battery to power a home or business or as a backup power source allows for greater savings on energy costs for consumers and business owners

3️⃣ EV owners can generate revenue or credits from utility companies by feeding unused power into the grid.

However, the challenges surrounding the infrastructure, regulation, and standardization of charging protocols and connectors must be implemented before this energy utopia can be realized.

But, there is no doubt that bidirectional charging will play a significant role in the future of clean energy.