Won Moon Joo
April 7, 2022
There is a growing pressure on charging infrastructure as the number of electric vehicles on the road increases. Obviously, more EVs mean a greater need for chargers.
For this reason, load management is a hot topic right now in the EV charging industry. Commercial or multi-residential buildings are installing more and more charging points, but they have to contend with challenges such as limited grid connection and power capacity. Load management can help to solve some of these issues.
In this article, we’ll explain what load management is, which challenges it can help to overcome, and how OCPP can be applied to dynamic load management as an ideal solution.
In simple terms, load management means distributing the available power amongst any plugged-in equipment and devices.
Load management is often applied to residential buildings, industrial sites, commercial premises, and more. The need for load management has grown due to the installation and use of devices that demand a higher power load. Load management helps to ensure a consistent energy supply, thus ensuring the efficient operation and charging of the devices.
For example, when we plug in a phone charger at home, we expect that the phone charger will work, while at the same time all the other “plugged in” devices will continue to work as normal.
We expect that the finite source of electricity that comes into the house (or site), is shared effectively so that all plugged-in devices and equipment remain operational.
The load management concept can be applied to EV charging.
Of course, the amount of electricity that an EV uses while charging is substantial. This is especially true when we consider multiple vehicles charging at the same time at a multi-residential building or parking lot.
We expect that no matter whether there are 2 or 10 vehicles plugged in, some sort of control system will automatically split and adjust the power to accommodate for the overall consumption of electricity.
The control system will also need to consider multiple factors, such as the total available capacity at that site and the maximum charging capacity of both the chargers and vehicles. This is important not just because we want the plugged-in cars to charge efficiently, but also for safety and efficiency reasons.
As mentioned previously, load sharing becomes more and more important as the number of chargers and vehicles increases.
For example, there are some scenarios where electric panels are oversubscribed purposely to accommodate more chargers than typically possible.
Let’s consider a parking lot with 50 spots and 50 chargers. In most cases, it is rare that all 50 chargers will be used at the same time. This could be for a variety of reasons, such as some parking spots are occupied by non-EVs, some vehicles have already finished charging and are simply parked, or the parking lot happens to be quiet at that time of day, etc.
Therefore, the site’s total capacity might be significantly less than the power required to use all 50 chargers at the same time, since it is anticipated that not all the chargers will be used simultaneously.
A dynamic load management system ensures that the power is split evenly across all the active chargers safely and efficiently.
In the event that the total load at the site exceeds the available capacity of the parking lot, for example, when all 50 chargers are in use, the Load Management system will limit the power supply to the chargers, allowing vehicles to charge but at a slower pace.
This form of managed charging allows more chargers to be installed at a location and grid upgrades can be avoided.
In the section above, we only discussed load management for EV charging alone. However, in some cases, the power supply supports non-EV-charging energy consumers such as building services.
Below we discuss these additional factors:
The load management system needs to include the cumulative load of the chargers, as well as other sources of electricity consumption.
For example, a parking lot may share a grid connection with a grocery store next door to it. When the grocery store is using less power than normal, the parking lot EV chargers can use more of the available capacity.
However, while the load between the store and the EVSE may be shared and change depending on the current consumption, a load management system ensures that the cumulative load at a site never exceeds the allowed available capacity.
A reliable Load Management system ensures that the circuit is not blown and a potential outage is avoided.
During times of high electricity usage, the total load shared by chargers at a site can be reduced or shifted to another time.
A system can respond to signals from the utility provider that warn against using a certain amount of power during a specific time period.
Also, if a site is experiencing busier than normal operations, the load management system can limit the amount of power that is available, so that the site does not exceed the limit. This reduces the power peak and flattens the electricity consumption curve, thus reducing the costs incurred by demand charges.
There are several different approaches to implementing effective load management.
Some charging hardware companies offer load management as an add-on. For example, local controllers offer load management for a wide range of chargers, from 5, to 15, 50, and 100. Other sites use multiple brands and third-party local controllers. These devices can offer a reliable way to control a group of chargers at a site.
However, there are some limitations.
What if you already have hundreds of chargers installed and want to incorporate load management?
Local controllers are expensive and revisiting every site to maintain and install additional hardware is painstaking and time-consuming. To go further, such as incorporating additional data points, including vehicle data, TOU Rates (energy rates), utility events (demand response), etc. you will need a real-time control system that can incorporate live data.
An alternative to a physical hardware solution is a cloud-based load management system. A charging point operator or a fleet operator can access a cloud-based EV optimization service through API integration.
A simple comparison to this is the Stripe payment processor. Through Stripe’s API, thousands of eCommerce websites across the world have access to a suite of payment solutions that help their customers pay for their products.
Similarly, applying an API-based software, like Ampcontrol, means that one seamless integration allows the entire charging point network to get access to Ampcontrol’s optimization services. No additional hardware is needed and API integrations are a common practice in today's tech world.
At Ampcontrol, we focus on providing optimization services through an API, since it is a reliable and scalable solution for charging points operators and fleet operators. Our service is based on the OCPP protocol, which is present in 80% of chargers worldwide. While OCPP is not a necessity, having a standard helps to reduce the time it takes to apply an integration.
By communicating with an OCPP backend system, Ampcontrol receives charging data and sends back charging commands.Ampcontrol’s dynamic load management utilizes OCPP’s smart charging modules to create a unique charging profile for every charger at a site.Through the smart charging module in the OCPP protocol, the central backend system can forward charging commands (charging profiles) to the charging stations. This allows flexibility for every charger to have different rates of charging over different amounts of time.
Ampcontrol’s dynamic load management algorithm ensures that power is split logically across chargers while ensuring certain limitations are met. Added features, like vehicle prioritization, Demand Response events, and peak shaving are elements that can be added on top of basic load management.
Read more about smart ways to charge your electric vehicles here: AI for EV Charging: How Ampcontrol Built A Brain To Manage Smart Charging
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