High power: understanding the strain that ultra-fast charging stations could put on the electrical grid

Electric vehicles (EVs) are becoming increasingly popular as a means of sustainable transportation, but the availability of fast and convenient charging stations remains a key obstacle to widespread adoption. Ultra-fast EV charging stations are designed to solve this problem by offering charging times of just a few minutes, allowing drivers to recharge their vehicles and continue their journeys quickly. 

However, as charge point operators consider attractive sites for building ultra-fast charging stations, they realize these stations require significant power consumption. How significant is “significant power consumption?” In this post, we will discuss this question

Types of charging stations

There are several types (levels) of charging stations, and each comes with a different power requirement. Level 1 and Level 2 charging stations are typically used for charging EVs at home or in other low-power settings. In contrast, Level 3 stations are designed to charge EVs in public locations rapidly.

What is the power required for an EV charging station?
The power requirements of the different levels of charging stations are:

• Level 1 Charging Station: This is the slowest type of EV charger. Level 1 charging stations use a standard 120-volt AC plug, the same type of outlet found in most homes. The maximum power output of a Level 1 charging station is 1.44 kilowatts (kW). An average EV has a battery capacity of about 50kWh, so a full charge using a Level 1 charger can take about 35 hours.
• Level 2 Charging Station: This is a faster type of EV. Level 2 charging stations require a 240-volt AC power source and can deliver up to 80 amps of current, with a maximum power output of 19.2 kW. In this case, a full charge would require over 2.5 hours.
• Level 3 (DC Fast Charging) Station: Because waiting 3 or 30 hours is impractical during on-to-go charging (your EV at various charging stations while you’re out and about), ultra-fast Level 3 chargers are required. This is the fastest type of EV charger. Level 3 charging stations use a 480-volt DC power source and can deliver up to 500 amps of current, with a power output of 150-350 kW.

Powering an ultra-fast charging station

If we want to charge a car with a 50 kWh battery in 15 minutes, we will need 200 kW of power. Is 200 kW a lot? (theaser – – yes(!)

1. Central Air Conditioning: A central air conditioning system can consume between 2 to 5 kW of power when running. This is one of the highest energy-consuming appliances in many households, especially during summer months in warmer climates.
2. Electric Water Heater: Electric water heaters can consume around 4 to 5 kW of power. 
3. Clothes Dryer: A standard electric clothes dryer typically uses between 2 and 6 kW of power.
4. Electric Oven: An electric oven uses approximately 1 to 5 kW, with larger and more powerful models using more electricity.

In short, an ultra-fast EV charger requires 50 to 100 times more power than common high-power appliances.

Upgrading a traditional gas station to support ultra-fast electric charging

Let’s assume that we want to install two charging ports to help EVs that pass by traditional gas stations. Let’s also assume that each charging port services one car per hour for ten hours a day. The total energy consumption would be:

2 charging ports * 10 cars * 50 kWh = 1000 kWh per day or about 30,000 kWh per month.

How much is this different than what the station is currently consuming?

The average power consumption of a gas station can vary with the size of the gas station, the number of fuel pumps, and more. However, a small to midsize gas station might consume in the ballpark of 50,000 kWh/year, so about 4,000 kWh/month. This averages to about 5 kW of power required, about the requirement of a residential water heater.

If the gas station includes a convenience store, we can look at the energy consumption of such a store. A study by the National Association of Convenience Stores (NACS) in the United States found that convenience stores used an average of about 51.5 kWh per square foot per year in 2018. A typical convenience store might be around 3,000 square feet, suggesting a total consumption of about 154,500 kWh per year or just under 13,000 kWh per month, or an average of 18 kW of power.

Thus, the typical requirement of a 2-port ultra-fast charging station (30,000 kWh per month) would roughly triple the consumption of a gas station with a convenience store.

But that’s not all. While the power requirement of a gas station or a convenience store is pretty much constant throughout the day, the power requirement of an ultra-fast charging station is far from constant: 200 kW when charging (typically a couple of hours per day) and pretty much zero when not charging.

Thus, the strain on the electrical grid could come in a combination of two ways: 

1. A 3-fold increase in the total energy that the station consumes
2. A 10-fold increase in the peak power consumption

Powering a multi-story apartment building

Now, let’s compare this to the power consumption of a multi-story apartment building. The exact amount of electricity a building uses will depend on many factors, such as the size of the building, the number of occupants, the building’s insulation, windows, and HVAC systems, as well as local climate conditions. 

However, for a rough estimate of the electricity consumption of a multi-story apartment building, we can use the U.S. Energy Information Administration’s (EIA) data on average monthly electricity consumption for residential units. According to ‌2019 data, the average electricity consumption for an apartment in the United States is around 914 kWh per month. Assuming there are 30 apartments in the building and they consume electricity at this average rate, the total monthly electricity consumption for the building would be:

914 kWh/apartment * 30 apartments = 27,420 kWh/month or an average power consumption of 38 kW.

Compare this to over 200 kW required during the charging process of a single EV using an ultra-fast charger, and you start to realize the magnitude of the problem.

Summary

As the number of EVs on the road continues to increase, the demand for public charging stations will also increase, and it’s essential to ensure that these stations can deliver Level 3 charging without overloading the electrical grid. 

Upgrading electrical grids to support Level 3 charging will take significant investments of time and money, both to keep the total energy requirement as well as to support high peaks of power consumption. We need to look for another solution until such an upgrade is completed. Power boosting and kinetic energy storage technologies allow charging stations to manage their power consumption and provide immediate Level 3 charging experiences without waiting for major upgrades to the electricity grids.