In our previous article you can find information about the potential of charging stations and learn what smart charging is. In a nutshell, it applies to efficient communication between entities related to the consumption, supply and flow of energy. The software behind the platform automatically analyzes and visualizes a mass of data in real-time. One of the uses is for automatic decisions about how and when EVs are charged. Efficient energy management can be used to monitor how an electric car is being charged, among other things, but over time it will become an essential feature of any system that wants to work both economically and cooperatively. It is anticipated that as more and more EVs emerge, the load on the electrical grid will require a well-tailored communication system and the implementation of protocols responsible for smart charging.
What is the difference between smart charging and bi-directional charging?
Bi-directional charging can refer to vehicle-to-grid (V2G) charging. This could also apply to the terms like vehicle-to-home (V2H), or vehicle-to-building (V2B). The feature is responsible not only for charging an EV but also can supply power back to the grid (or home). Effectively it enables to treat car battery as an extra source of charging power, storing energy that can be re-used.
Smart charging goes one step further, enables efficient communication between charge points and grid operators. All in order to manage charging points remotely and to optimize energy consumption and costs. By 2030 it is expected to have smart charging protocols developed and implemented, to avoid network overload. Smart charging allows EV owners, businesses, and network operators to control how much energy is taken from the grid and when. By balancing the load, it also offers to charge at lower rates, when the demand for energy is lower, e.g. at night.
How does bi-directional charging work in practice?
To charge an EV, one needs a charger to convert AC (alternating current) electricity sourced from the grid to DC (direct current) electricity. This happens via a built-in converter (either vehicle or in the charger). If the energy stored in the EV’s battery is to power home or sell it back to the grid, the DC electricity from the car must be converted again to AC electricity. This mechanism happens via bi-directional charging. The feature is already adapted in the US, UK, and EU. It is used to power houses, office buildings. How much power do we talk about? Nissan says the 62kWh battery in the Leaf e+ can store enough energy to power an average Japanese home for up to four days.
Do all vehicles support bi-directional charging?
No. A CHAdeMO protocol & charge port facilitates bi-directional charging, (e.g. Nissan Leaf is equipped with CHAdeMO). However, most vehicles use the Combined Charging System (CCS) standard right now. Existing models will probably require V2G integration as an aftermarket resolution. Many car manufacturers, such as BMW, Honda, Volkswagen, and Tesla, are considering introducing bi-directional features in their future electric vehicle models.
Does V2G affect car batteries?
E.g. According to the information provided by Nissan, two-way charging does not have a damaging long-term influence on the battery because charging and discharging are less intense than driving. Bi-directional charging does not affect the producer's battery warranty as long as the charger used is approved for use by the manufacturer.
What are the most popular features of smart charging?
Among features smart charging provides, one can distinguish power sharing, power boost and dynamic power sharing. Each is relevant to the ecosystem and to individual actors.
A review of nine European V2G projects in 2020 by Cenex found that the common pattern for V2G of creating income through energy trading is only one of the opportunities. Other key value propositions highlighted are resilience, the benefits to society, enhanced battery management and self sufficiency.
Smart charging offers:
Power sharing can be defined as load balancing or leveling. How does it work? Each site is limited when it comes to power access. Bigger demand for energy would mean electrical infrastructure upgrades. Smart charging allows avoiding these expenses. Network operators or sites with many chargers can divide the available energy capacity proportionally over all operating EV charging stations. Optimal distribution with smart charging helps to avoid costly expenses.
Power Boost prevents households from surpassing maximum energy capacity. Power Boost comes with help to the situation when electricity is consumed simultaneously on a high level by many devices. It balances the load dynamically among the charger and the rest of the devices. When reaching the highest capacity, a smart charging control system automatically reduces the power consumed by an EV. The case scenario even includes pausing the charging session till enough power is available again.
Dynamic Power Sharing = Power Boost + Power Sharing.
With Dynamic Power Sharing (DPS) a building’s energy demand is monitored and measured against its maximum admissible capacity. When demand is low, the spare available energy is transferred to the charging network. The smart charging system automatically covers the available power among all chargers. On the contrary, if the site energy demand is equal or larger than the maximum authorized rate, no power is supplied to the charging points. Smart management allows keeping in great balance the charging network’s demand.
Open Smart Charging Protocol (OSCP 2.0)
To cover and support unified communication, Open Charge Alliance developed in 2015 Open Smart Charging Protocol (OSCP). An updated version was released in October 2020. The protocol was first designed for communicating a forecast of the locally available capacity to Charging Station Operators (CSO), to enable them to fit the charging profiles of the EVs within the boundaries of the available capacity. The new version specifies use cases in which the messages are applied in more universal terms, which was specifically aimed at smart charging of EV by a Distribution System Operator (DSO). Behind the use of generic terms is the specification not limiting the possibilities of the protocol to smart charging EVs. This is a top-down integration of EVs in larger energy ecosystems, including Photovoltaics (PV), stationary batteries, heat pumps and other devices. Based on JSON / REST, offers also additional types of forecasts (generation, consumption, fallback) and a message for reporting errors. The OSCP is available to download at the Open Charge Alliance website.
The future of charging is smart
As we see bigger demand for conscious energy consumption and distribution, features and smart charging protocols soon will become a necessity. The multi-level changes we are witnessing dictate sustainable and smart energy distribution. Open standards and dedicated protocols are essential for unified communications, and it is expected that soon implementation will be legally binding for market participants.