Smart charging refers to any kind of EV charging (uni or bidirectional) in which the charging time and rate can be controlled by a “smart” device, rather than a manual on/off switch. This is done using data connections between the EV and the charger. Consider Smart EV charging apps, for instance, which allow you to control how long your EV is charged by using your smartphone. With smart charging, cars can be plugged in but they don’t have to actually be charging the whole time. Instead, individual EV owners or energy companies can decide when it’s most efficient to charge energy in terms of demand and cost, depending on the country and the energy operator. This can sometimes bring economic benefits for customers. For instance, many energy companies may offer preferential rates for night-charging. This also helps avoid situations in which a large proportion of EV owners charge at the same time, overloading the energy supply grid.
What Is Bidirectional or “Two-way” Charging Used For?
Bidirectional charging allows energy to flow both ways - in and out of your car. But where exactly does the energy go when it’s flowing out of your car?
V2G is when a bidirectional EV charger is used to supply power (electricity) from an EV car’s battery to the grid via a DC to AC converter system usually embedded in the EV charger. V2G can be used to help balance and settle local, regional or national energy needs via smart charging. It allows EVs to charge during off-peak hours and give back to the grid during peak hours, when there is extra energy demand. This makes perfect sense: cars sit in parking spaces 95% of the time, thus with careful planning and the right infrastructure, parked and plugged-in EVs could become mass power banks, stabilizing the electric grids of the future. In this way, we can think of EVs as big batteries on wheels, helping to make sure that there is always enough energy for everyone at any given time.
V2H is when a bidirectional EV charger is used to supply power (electricity) from an EV Car’s battery to a house or, possibly, another kind of building. This is done via a DC to AC converter system usually embedded within the EV charger. Like V2G, V2H can also help to make balance and settle, at a larger scale, local or even national supply grids. For instance, by charging up your EV at night when there is less electrical demand and then using that electricity to power your home during the daytime, you could actually contribute to reducing consumption during peak periods when there is more electrical demand and more pressure on the grid. V2H can, therefore, help make sure our homes have enough power when they most need it, notably during power outages. As a result, it can also reduce the pressure on the electricity grid as a whole.
Both V2G and V2H may become more important as we move towards totally renewable energy systems. This is because different renewable energy sources tend to produce variable amounts of energy depending on the time of day or season. For instance, solar panels clearly capture the most energy during the day, wind turbines when it is windy, and so on. With bidirectional charging, the full potential of EV battery storage can be realized to benefit the entire energy system - and the planet! In other words, EVs can be used for renewable load following: capturing and storing excess solar or wind power when it is generated so that it can be made available for use during times of high demand, or when energy production is unusually low.