EVs keep the lights on as power outages hit – analysis
New analysis shows those affected by power outages are using EVs to power homes
By Colin Walker
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With reports on social media that some people affected by the power outages in Spain are using their EV to power their homes, [1] new analysis by the Energy & Climate Intelligence Unit (ECIU) has revealed the extent to which EV owners can rely on their vehicles to power their homes during such an outage.
This analysis has found that the average EV, even using just 60% of its charge, could provide the equivalent of 5 days of power for the average Spanish household, allowing Spanish EV drivers to keep the lights on. [2]
The last major power outage experienced in the UK was caused by lightning strikes knocking out a gas power station. Most power outages are caused by disruption to the distribution network, for example, when storms uproot trees which then damage power lines. In the UK, the average EV could provide the equivalent of almost 6 days of electricity for a typical UK household, again using just 60% of its battery capacity.
EVs that have V2G (vehicle to grid) or V2H (vehicle to home) functionality are able to send energy back to the grid and/or home via an appropriate bi-directional charger. Besides allowing owners to keep the lights on during a blackout, this also enables them to make money by charging up when electricity is cheap – such as night-time, or when renewables energy is plentiful – and selling it back at peak times when electricity is more expensive.
Analysis by the ECIU has found that this ability could allow EV owners to make £630 a year, simply by plugging in for 2 hours around peak demand in the evening and using a fraction (around 20%) of the EV’s battery capacity. This would come on top of the hundreds, even thousands, of pounds in savings that coming from running an EV compared to a petrol equivalent. [3]
Commenting on the analysis Colin Walker, Head of Transport at the Energy & Climate Intelligence Unit, said: “As well as reducing emissions and saving their owners hundreds of pounds in running costs, EVs are also capable of adding resilience to their owners’ homes. More and more EVs are arriving on the market that are capable of returning power to the home. In an unpreceded blackout like the one we just saw in Spain, these EVs will allow people to keep their lights on, their fridges cold and their wireless routers running for days.
“The benefits don’t just stop there. Owners of V2G-capable EVs will also be able to charge their cars when electricity is cheap, and sell it back to the grid when demand is higher, earning them hundreds of pounds a year”.
Alongside people affected by the power outages in Spain using their EVs to provide a replacement power supply for their homer, other examples exist from other countries that have also experienced blackouts in the past. An article in Spain, which looked at the role that EVs can play in keeping homes powered during a blackout, highlighted the example of a former environment minister in Chile who used his car to power his home during a blackout in 2024. [5]
1. For example, one resident posted, “I have the refrigerator and router plugged into my mg4. Thank goodness.” https://x.com/AbLuismi/status/1916983066871976016. In another post, a resident points out the car batteries he has installed that allow him to keep his house running in the midst of a blackout - https://x.com/Angel_gaitan_of/status/1917107832307990976.
2. The average EV battery capacity is 71kWh. The analysis used 60% of this capacity, in line with discharging from 80% to 20% capacity as advised by EVs manufacturers for general use of an EV, although they can be used outside of that range. Average household electricity demand is 3,300kWh per year (9 kWh per day) in Spain, and 2,700kWh per year (7.4kWh per day) in the UK.
3. This analysis was conducted on the same basis as in the report Power plants on wheels (ECIU, 2023), using the following assumptions: 2hrs of battery discharge during peak demand, at 7kW of power, giving 14kWh (just 20% of the typical EV battery); 3kWh of household demand met by the EV during those peak hours (noting that demand would likely be higher, but only power levels up to 7kW would be met by the EV), avoiding imports at the price cap unit rate of c.25p/kWh for 2025 i.e. 75p; and 11kWh of exports, earning a tariff of 15p/kWh (e.g. Outgoing Octopus tariff) i.e. £1.75, giving a total benefit of £2.40 per day. If this was repeated 5days a week, i.e. 260 days in a year, the annual benefit would reach £630 (numbers might not sum due to rounding).
4. For example, one resident posted, “I have the refrigerator and router plugged into my mg4. Thank goodness.” https://x.com/AbLuismi/status/1916983066871976016