Won Moon Joo
January 25, 2022
Imagine a big box store like Target or an office building with 10 chargers in the parking lot.
Let’s say at 9 am, employees and customers start arriving at the building and parking their cars.
Some of these people drive EVs and charge their vehicles in the parking lot. Charging one or two EVs may seem like it would have very little effect on energy consumption.
But, by midday the parking lot is full and all the charging stations are being used. In other words, now there are 10 EVs charging. The electricity usage from the EVs ends up accounting for the majority of the site’s available capacity (i.e. the total available power at the site).
How will this affect energy supply to the site, both in terms of reliability and cost?
In this article, we’ll discuss how electric vehicles and buildings need to be considered together, and a combined approach to the charging infrastructure needs to be taken. We will also define the term ‘baseload’ and suggest ways to integrate the building baseload into EV smart charging.
A building baseload is the amount of power the building needs to meet the minimum energy consumption. Typically, a baseload is measured in Watts (W).
Oftentimes, the baseload considers services like lighting, refrigeration systems, HVAC, and other devices, which can easily account for more than half of a building’s energy use.
The baseload can provide insights into energy usage throughout the course of a day. For example, below you can see a baseload of a typical single-family household.
Not only is it important to reduce the baseload of the building, it is also important to consider how to reduce the peak demand by considering the baseload when utilizing charging stations.
Accommodating a charging site’s available capacity by using a building’s baseload can help to make smarter charging decisions.
If the chargers and buildings are behind the same meter, there is a potential that the charging of the EVs could far exceed the building’s electricity use.
Given that a single DC fast charger could provide up to 75 kW of power, the amount of power needed when all of the vehicles are charging at a site can be excessively high.
In our example, if all 10 charging stations are being used at full power, they would account for 750 kW of power.
To put it in comparison, a family household has typically a maximum power demand of less than 10 kW. This shows why the power demand of EV charging can quickly become an overwhelming problem.
Let’s look at the building baseload again.
A large retail store with air conditioning and refrigerators might have a power demand of around 700 kW. The power needed will also fluctuate wildly during the day. For example, a study shows that fluctuating power demands are ∼641 kW in the evening and ∼1.1 MW midday.
Below you can see an example of a store’s baseload.
Consequently, we see how a parking lot with just 10 chargers can easily double the power demand for the site owner.
In fact, according to a study, the addition of electric vehicle stations could increase the monthly peak power demand at a site by over 250%.
Also, many experts anticipate that in the near future businesses will need to provide even faster-charging power to accommodate the desire for shorter dwell times at public stations.
These scenarios stress the importance of controlled EV charging to minimize the requirements for infrastructure upgrades, peak demand charges, and maximizing any on-site generation or batteries.
Incorporating the power demand of buildings (i.e. baseload) is going to become increasingly important as EVs become more commonplace and charging demands grow.
There are many benefits of considering the baseload to help calculate charging profiles for the chargers.
Firstly, it gives you flexibility. There isn’t just one single rule for available capacity. Creating a brand new site with kWs of grid power would be costly and it would take a long time to get authorization and build the site. Combining the building baseload and EV charging load becomes critical to enable a fast expansion of electric vehicles.
Secondly, by combining the capacity of the building, electricity can be shared between the building and charging stations depending on actual usage at different times of the day. For example, an intelligent charging system can share the available power between the building and the electric vehicles.
Dynamically sharing the available power enables an active control system that can flexibly monitor charging operations.
In some cases, a control system could even accommodate on-site batteries or power generators, allowing you to install more fast-charging stations or reduce the total utility fees.
At the moment, most EV charging is done at home, where vehicles are plugged in and charged overnight.
However, this is expected to shift to public options as more consumers purchase EVs who don’t have home-charging options or travel away from home frequently.
We expect an influx of charging options at retail locations, office buildings, and other public locations.
So given this anticipated shift to public charging, utilizing the building load can provide many benefits and overcome challenges.
Smart charging systems, such as Ampcontrol, are at the forefront of optimizing EV charging and are set up to combine building baseloads with EV charging stations.
Read more about using smart charging on charging sites, and how to scale efficiently, here.
Ampcontrol is a cloud-based software that seamlessly connects to charging networks, vehicles, fleet systems, and other software systems. No hardware needed, just a one-time integration.
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