Where Will Solar Fit Into the EV Charging Equation?

Article By : Patrick Cunningham

Solar power may provide the means to offload stress from existing power grid infrastructure as EV adoption steadily grows.

The world is experiencing an enormous drive to accelerate the adoption of electric vehicles. While the push for this technology comes from a good place, many aspects of the effort are clearly premature.

First and foremost, the existing power grid infrastructure does not seem to be growing at the rate necessary to support the widespread EV adoption that proponents envision.

While this situation is alarming, several potential solutions are available. Specifically, solar power may provide the means to offload stress from the grid as EV adoption grows.

EV solar charging (Source: Shutterstock)

The EV push

In the automotive industry, many believe EVs are an essential component to any plan for stopping or reversing the climate crisis. There is no denying that EVs are cleaner than internal-combustion–engine vehicles.

The adoption of EVs has been relatively slow in the United States: It stands at about 4%. To drive that number up closer to the 50% seen in Europe and ultimately 100%, both the private and public sectors have ramped up efforts.

Specifically, the government has begun offering attractive subsidies to make and buy EVs.

At the same time, automakers are developing new technologies and refining production processes. The aim here is also to drive down costs and improve performance so that EVs will become a more realistic and cost-effective choice for the consumer. Many experts believe that within the next five to six years, the cost of an EV in the U.S. will be lower than that of a vehicle with an internal combustion engine. When this happens, the adoption of EVs is projected to grow exponentially.

Putting the card before the horse

Numerous obstacles stand in the way of widespread EV adoption in the U.S.

First, the U.S. does not have enough electricity in the grid to support a massive influx of EVs. In 2020, the U.S. grid had an estimated capacity of 1,117 TW of electricity. If all cars were EVs charging at 7 kW, the grid would require a capacity of over 2,000 TW.

Beyond power generation are the limitations of grid infrastructure. The U.S. does not have enough transmission lines, distribution lines, substations, or any of the other crucial pieces of grid infrastructure required to recharge EVs on the road. Even at the current low adoption rate of 4%, we are witnessing the limitations of grid infrastructure.

Today, the governments of Texas and California have begun asking residents to restrict the hours they charge their vehicles during the summer months, as their existing grid infrastructures are not equipped to handle the load. Ignoring these restrictions could result in blackouts and brownouts, especially in residential areas where the demand is the greatest.

Consumers are being fed conflicting messages: On one hand, governments are pushing hard for the adoption of EVs. And on the other hand, they are restricting people’s ability to charge those vehicles.

By putting the cart before the horse—or, in this case, the EV before power generation and distribution—the government and the auto industry are running the risk of a significant loss in consumer confidence and possibly a big setback for the EV industry overall.

The role of solar

While the solution to these problems is multifaceted, the expansion of solar power may help to resolve the capacity limitation.

Today, an estimated 85% of all EV drivers charge their vehicles at home in their own garages. This indicates that the vast majority of EV demand comes from private locations, not public charging stations.

With this in mind, one way to mitigate the capacity limitation is to take EV charging off the grid. What if every home with an EV was equipped with solar panels and was able to generate an appreciable amount of its own power? In this situation, the demand on the grid from EV charging could be significantly reduced.

However, solar panels alone would not be a viable solution. It takes anywhere from 7.2 to 10 kW of power to charge an EV battery. A single residential solar panel can expect to achieve nearly 400 W of output. So to achieve enough power output from solar alone would require hundreds of panels in an array, which wouldn’t be economically or logistically feasible for the average residential home.

A more realistic solution would be to couple a smaller solar array with a battery bank—one that could store enough energy to realistically charge an EV.

In this setup, the solar array could charge the battery bank over time so that when an EV plugs into the home for charging, the array has enough energy stored that it can fully charge the vehicle. Here, the battery bank acts as an uninterruptible power supply and can enable mass EV charging without the need to burden the grid during the 85% of charging that occurs entirely at home.


This article was originally published on EE Times.

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