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It is 12 noon - do you know where your car is?

For most privately owned cars, the most common answers are: at home, at work or somewhere on the road.

But why does this matter?

The increased installation of solar panels is leading to a more pronounced "duck curve" in many power grids - with an over-supply of electricity around noon on sunny days and demand ramping up rapidly in the evening as the sun sets and people are returning home.

Large amounts of energy storage will be needed to "flatten the duck". While VRES like solar and wind have generally become the cheapest sources of electricity production, storage is still very expensive.

At the same time, we are seeing a strong trend to replace traditional cars with battery electric vehicles (BEV). For better or for worse, BEV are essentially large batteries on wheels. Because of this battery, BEV are significantly more expensive to manufacture and have a roughly 30% higher initial "carbon debt" than comparable ICE cars. On the other hand, once purchased, their carbon footprint improves the more they are (legitimately) used.

According to the EV database, the average BEV battery size is about 70kWh and the average energy consumption is 19kW per 100km. The average daily distance driven per car is about 30-40km (EU - US), which means that the average BEV needs about 6-8 kWh of energy per day for its driving needs and that a battery charge can last on average 8-10 days.

In order for electric cars to help "flatten the duck curve", charging stations would need to be available where the cars tend to be in the middle of the day - which for many commuters would be on corporate parking lot. Taking advantage of excess energy at mid-day on a sunny day will also require a smart charging infrastructure which delays the charging to the right time based on expected electricity supply as well as knowledge of the car's expected driving schedule.

Average daily electricity consumption (without heat and hot water) for a single person household in Switzerland is estimated around 6kWh - mostly for cooking and refrigerating food as well as washing and drying laundry. Assuming a 10 minute shower per day, we can add an additional 6kWh for hot water. Heating is harder to estimate, depending on the age and state of building as well as the climate and season.

Which means that the average BEV could support the average total electricity needs of its owner for 3-4 days without recharging, making it a significant source of potential long-duration storage.

For this use-case to work, cars would need to be equipped with bi-directional chargers (currently only in a few models) as well as a bi-directional charging connections and energy management systems at home or wherever the store electricity should be consumed.

Energy economics alone will unlikely justify the necessary investments. However, we also generally do not make automative purchase decisions purely on economic reasons - otherwise many of us would not own a car or at least not as large a car as we do. Beyond the utilitarian purpose of mobility, cars often represent intangible "value beyond" like fun, freedom, independence, rugged individualism, identity or security.

The idea of increased autarky and energy independence from the grid might well align with the mindset of many owners of large premium BEVs. As severe weather becomes more common across the globe and the power grid might become less reliable, being able to use the car as backup power for the whole house could provide a sense of security for which many owners are willing to pay a premium.

A particularly fitting symbol for this brand of rugged individualism might be the electric Ford F150 lightning pickup truck with a 130 kWh battery. Which is more than large enough to power even a large house for days if not weeks.

For private car owners, V2G (vehicle to grid) might never be a particularly appealing use-case, while home backup power and increased autonomy (V2H: vehicle to home) might be more in line with the mindset of private car owners around freedom or independence. If car batteries are being used to supply electricity, most of the action might be behind the meter (BTM).

If a car is typically not at home in the garage during the mid-day solar peak, then it cannot the store excess production from the rooftop solar panels. However it could store the excess power from solar panels at a corporate office parking lot, taking the energy home to be used in the evening and over night.

If BEV are to become the central hub of a BYOE ("Bring Your Own Electricity") solution, they need to become much better at predicting their user's mobility needs, as well as the energy supply and demand profiles for each of the locations where the car is regularly connected to a grid.