Last weekend heralded the arrival of Storm Éowyn, an "an extremely powerful and record-breaking extratropical cyclone" according to its wikipedia entry. Hundreds of thousands of households lost electrical power, with the peak figure nearing a million premises. Many are still without a return of power yet, with people seeing dates into February (where we are now!) for when they will get it back. The damage to the country has been significant and one that will take a lot more time to clean up from.
Which brings us to where EVs have found themselves in the limelight of this all. There have been many reports of electric vehicles powering homes using Vehicle-to-load technology, we spoke to RTE News about it here, and we have been inundated with enquiries and requests for information. For many of us in the EV space, we have seen the benefits of EVs for many years beyond sustainable transport and how they will play a crucial and extremely important role in a robust and reliable renewable grid. Now the general public is interested and they want to know more. So with that, let's get you up to speed!
To start with, let's look at what's been happening and where the interest has thrown open the current conversation. People in their EVs have been posting and sharing their stories of power loss to their home, then they say how their car is now powering the essentials of their home, or running critical medical devices for family, friends and neighbours. So what is this technology in an EV that allows this?
Well, for the absolute majority of what has gone on (and we will ignore the Solar PV + battery storage setups for another time as a means to power your home in a power loss from the grid), people have been using Vehicle-to-Load (V2L). V2L makes up a part of the V2X family of technology, of which there is: Vehicle-to-Grid (V2G), Vehicle-to-home (V2H), vehicle-to-load (V2L) and vehicle-to-vehicle (V2V). Lots of V2X going on there, I'm sorry...
In simple terms, V2L is your vehicle acting like a generator. That is, at any point in time, you plug the correct adaptor into your vehicle that is V2L capable and you can use it to provide power from 2kW up to 3.6kW. These adaptors plug into the Type 2 AC port on your vehicle where you normally charge the vehicle at home with, and can come with a single 3-pin plug on the end or with say a 2-4 gang extension board on the end of a long lead. With this, you can now plug in the essentials like the fridge-freezer, a kettle for hot drinks, a small room heater or in some cases the trusty airfryer!
V2L does have its limitations as it comes with a simple 3-pin plug setup by default and is not hugely powerful to a home with heat-pumps or electric showers. But for keeping the power on to the essentials, it's a huge step forward. However it can go further than this and can be used to power your home more like an actual generator. As in, using your electric vehicle as a generator rather than using an actual petrol or diesel generator to power your home directly. This is known as Vehicle-to-Home (V2H).
Those who are super prepared have installed change-over switches to their homes. This disconnects the house from the main grid supply (and we must emphasise, in all cases where there is a storm or grid outage, you must do this to protect ESBN and anyone working on the power lines!) and then lets you 'change-over' to your secondary power connection, your generator input. With this, you can switch off the non-essentials in the home at the consumer unit (fuseboard) and in this case the V2L adapter can be connected to the generator input to the home and run the essentials directly. Now, again, we must emphasise that this should be done correctly in the setup of your home and its use so that no one can be injured due to incorrect wiring or electricity coming from your home to an external mains power-line that should be unpowered. But done correctly, you are now running a subset of your home with your vehicle!
We have just touched on one part of the ecosystem of an EV in the above with V2L/V2H. So the question is, what vehicles have this? Well, the best place to look is a site called ev-database.org and to use the filter on the system for "Vehicle-to-Load" for this setup. This will give you a complete list, and at the time of writing, there are 124 models that have this functionality. Now, not all models will be available in Ireland, and some models will be dependent on their spec to have this, but for the initial point to work from you are looking at brands such as Hyundai, Kia, MG and BYD.
We will note that V2H is not a clear cut on EV-database.org and falls closer to V2G. Which brings us to!
Moving beyond V2L/V2H, the next major step is Vehicle-to-grid (V2G). This has been around for a long time, in fact from pretty much the beginning of electric vehicles. The Nissan Leaf came with V2G capability from the start, but has never taken off in the way it should have. But to simplify what V2G is and how it differs from V2L, V2L cannot be used while you are connected to the grid, (see changeover switch above). Our homes operate at 240V and 50Hz. This 50Hz frequency needs to be detected and in-phase to use safely when the grid is live and connected. V2G does this, V2L cannot.
The frequency on the grid is in part the initial issue around V2G charging and use, cost. While the Nissan Leaf has been available with the ability to run your home alongside the mains grid (i.e. it's built to detect the grid frequency and work with it, and not just in a power loss), the cost of the units to allow this has been prohibitive. This means that while the Nissan Leaf is capable of running your home, the cost to do so does not make it viable to do so. And unlike V2H in use through a 'changeover' switch which may cost €1,000 to €1,500 to install, V2G costs can be multiples of this and currently there is no official support for its use with ESB Networks, but it has been trialled and to our understanding legislation is being worked on in relation to this.
This is changing as many automotive OEMs are bringing vehicles to market with V2G capabilities through AC solutions. This should bring down costs and open this up for more homes. V2G will help the grid as we move to 80% renewables and beyond. You will be able to charge your car during times of excess renewable generation when costs are low, and then pull from the battery in the vehicle at peak times when costs are high, thus saving you in your home on costs, and reducing over-building the grid for those peak demands. While vehicle electrification is essential to reducing our dependency and use on fossil fuels, they will play an important part in a renewable grid future, and will add to grid reliability and robustness.
Ok, ok, but a battery in your vehicle has to get power from somewhere. Yes it does. The majority of people with a V2L vehicle had filled their vehicles before Storm Éowyn hit. Some didn't need it, many did. Depending on the size of the battery in your vehicle, you could have somewhere from 40kWh, to 70/80kWh on average. Going back to running the essentials, if you are using electricity at 2kW per hour (2kWh), you have between 20 and 40 hours of use in your vehicle.
Most loads will be less than this. My own home I have a fridge-freezer, internet router, TV's on standby and other devices that sits between 200-300W. If I have a 80kWh battery, keeping the minimum essentials on would use up the battery in 266 hours, or 11 days. With one caveat, most V2L equipped vehicles will stop you at ~20% battery State-of-charge (SoC). Why? Because that still leaves you with between 30 and 70 kms of range. For many people who we have seen without power for multiple days, this means that they run their house until it reaches 20% and then they are driving to the nearest DC fast charger which is operational (and the majority are online!) and topped up their vehicle. This would only take a few hours at most and could be coordinated with getting essentials for the home.
In all of this, and to conclude, electric vehicles are a fantastic means of transport and we are now seeing the additional capabilities these vehicles have. V2L and V2G have huge benefits and will only make these sorts of events more manageable in the long term. While a storm is not how these benefits should be made aware, it is worthwhile understanding what is available and what can be done.