Electric cars have huge battery packs that can power a house for several days, or even a whole week. This technology is called Vehicle to Home (V2H).
The maths is simple – UK households consume on average between 8kWh and 10kWh per day, a paltry amount compared to the capacity of most electric car batteries.
For instance, the Vauxhall Corsa-e has a 50kWh battery. If your house uses 10kWh per day, this diminutive electric car will give you up to five days of power (depending on conditions like outside temperature).
Why would you want to do this? The obvious reason is to move off-grid and beat rising energy costs. You could charge your car for free at a supermarket, or for very little on an EV tariff, and run your house off your car battery for peanuts.
Unlike a Tesla Powerwall, which acts as fixed local energy storage for your house (usually for solar charging), V2H uses your car battery for power.
Another way of looking at V2H is as a supplementary power source to the grid which can reduce your consumption of virgin electricity.
Households with vehicles capable of bidirectional charging could take advantage of fluctuating electricity prices by charging their car batteries when prices are low and then using the stored energy to power their homes when prices are higher. The prerequisite is owning compatible electric vehicles that support transferring power from the battery back to the electrical grid or household.
What is V2H?
Vehicle to home (V2H) is a new technology that allows the energy stored in an electric vehicle to be used as a power source for the home.
In a nutshell, this technology is like having a portable energy storage unit that can be used to reduce electricity bills and provide extra power during a power outage. V2H works by connecting the car battery to the home’s electrical system.
This connection allows the energy stored in the car battery to be used to power the home. The connection also allows the car’s battery to be recharged from the home’s electricity, which can be a great way to save money on energy bills.
The main challenge of V2H technology is safety. As with any technology involving electricity, it is important to make sure that the connection between the car and the home is secure and reliable.
Additionally, it is important to make sure that the car battery is compatible with the home’s electrical system to ensure that it is able to deliver the right amount of power.
V2H technology also has to be able to handle periods of high demand in the home, such as when appliances are being used. This requires the car battery to be able to provide the extra power needed while still maintaining its own charge.
How does V2H work ?
V2H works by transferring power from your electric car battery to your distribution board or an energy storage system like the Tesla Powerwall.
When V2H feeds your distribution board, power is sent to appliances, sockets and devices, with load management to control the distribution.
When V2H feeds an energy storage system, power is sent to a large battery back built into your home that stores energy for distribution later.
To connect a vehicle to a home, you will need a power inverter (charger), a battery, and wiring to connect the power inverter to the battery and the home.
Solar panels and V2H
An innovative study published on ScienceDirect demonstrates how to slash your home energy bills through smart coordination of electric vehicles and rooftop solar panels. The researchers developed an optimisation algorithm that considers both V2H charging and cheaper workplace/public charging options. It determines the ideal solar and battery sizes to minimise costs, while exploiting time-varying electricity rates.
Remarkably, the approach can reduce total expenses by up to 31% compared to petrol cars. Additional savings come from discharging EV batteries to power households during peak pricing periods. The method quantifies optimal systems for different EV uses and available charging infrastructure. It also reveals surprising trends – cheaper night-time rates drive larger solar installations, while exorbitant peak prices shrink panels and batteries.
As EV adoption accelerates, this strategy provides a customisable roadmap to leverage their storage capabilities. Households can tap into underutilised energy from solar and EVs to slash bills and unplug from the grid. The scalability across various scenarios makes this a widely applicable blueprint for integrating renewable transport and energy in the future.
Can I power my house with my electric car?
An electric car can power your home, but only if it has bi-directional charging and you have a smart charger with bi-directional charging.
While V2H technology has clear benefits, there are few electric cars on the market today with bi-directional charging to accommodate it.
Volkswagen will add V2H technology to vehicles with its 77kWh battery by the end of 2022 with an over the air update.
For V2H to work, an electric car needs to have bi-directional charging, and you need a smart charger with bi-directional charging as well.
Your electric car sends power to the V2H-enabled smart charger, which then handles the transfer of power to your distribution board and energy storage system. Your smart charger acts as a middleperson to collect energy data.
Vehicle to home benefits
There are two big benefits to V2H:
- Beat soaring energy prices – charge for free at supermarkets and for very little with an EV tariff, then run your house off that energy.
- Avoid power cuts – Storm Arwen left 30,000 households without power last year. With V2H, those homes would have been fine.
Energy storage can provide a variety of benefits to homes with electric vehicles. It can be used to store energy from the vehicle to power the home during off-peak hours. This can help reduce energy costs. It can also help provide backup power in case of a power outage.
In addition, energy storage can be used to balance the grid, by storing energy from the vehicle when demand is low and releasing it when demand is high. This can help reduce peak demand and improve grid reliability.
V2H vs V2G vs V2L – what’s the difference?
V2H, V2G and V2L are all bi-directional charging features, however, the technologies that enable them are slightly different.
Vehicle to home (V2H) is a bi-directional charging feature that uses your electric car battery to power your home, sending power to your distribution board or an energy storage system like a Tesla Powerwall.
Vehicle to grid (V2G) is a bi-directional charging feature that sends power in your electric car battery to the grid. With a V2G charger, you can sell energy back to the grid, although there isn’t a mechanism in the UK for this yet.
Vehicle to load (V2L) is a bi-directional charging feature that uses your electric car battery to power devices and appliances directly. With an adapter, you can power 3-pin appliances and charge other vehicles at 3-pin speeds or faster.
Will V2H activities degrade battery life?
As EV batteries age and undergo charge cycles they lose charge capacity and power capability. V2H and V2G create additional charge cycles, so logic dictates that V2G activities will degrade battery life.
However, it isn’t so clear cut.
“Analytical results [from the study] show that providing V2G services does not necessarily accelerate the battery degradation; in some cases, it even mitigates the ageing process,” this study concludes. “A case study undertaken shows that, compared to non-V2G scenario (no battery discharging to the grid), battery capacity loss under V2G is reduced by 13.51%.”
So, V2H and V2G activities won’t degrade battery life by any meaningful amount. In fact, predictable activities could extend battery life. However, the study is clear that you need an ‘optimised’ or ‘smart’ V2H/V2G system, i.e. a smart charger.
It’s important to remember that lithium-ion batteries degrade over time and with repeated charging cycles. Degradation is caused by a variety of factors, including heat, age, and overcharging. Reducing heat, using quality chargers, and avoiding overcharging can all help reduce battery degradation.
In the future, we might all power our houses with electric cars, or at least some aspect of them. What a time to be alive.
