How Europe can unlock the huge potential of ‘batteries on wheels’

A market failure is preventing electric vehicle owners from using their cars’ batteries to power their homes and back up local grids. Following up on its Grid Action Plan, the Commission needs to propose the necessary regulatory measures to give drivers a right to bidirectional charging, and chart a path to making Europe a leader in this exciting technology, writes William Todts.

William Todts is executive director at the campaign group Transport & Environment.

A market failure is preventing EV owners from using their cars’ batteries to power their homes and back up local grids. The EU should give drivers a right to bidirectional charging, and chart a path to making Europe a leader in this exciting technology.

Images of Ford’s electric pick-up truck powering American homes have gone around the world. People found it novel and exciting to see a car keep the lights on when electric grids went down. I’m not a fan of pick-up trucks but I do love the way Ford sold the dream of a battery on wheels powering our homes. The idea has been around for at least a decade. The real shock is we have made so little progress on making it a reality.

We can’t afford to not unlock the potential of batteries on wheels. Battery electric vehicles sales are almost at 20% in Europe and they will rise rapidly. Intermittent wind and solar electricity provide 22.5% of our power and are expected to grow to 45% by 2030. More renewables require more flexibility and that’s exactly what electric vehicles can provide. If only 20% of EV battery capacity could be activated, it could cover close to 90% of the short-term flexibility needed in 2030. That’s exactly how we avoid spending billions on home batteries, unnecessary grid upgrades or subsidies for peak gas power plants that only switch on during rush hour.

EV owners are seven times more likely to have solar panels than petrol drivers. Being able to use EVs as energy storage would be a big win for consumers, saving the expense of an expensive home battery, and allowing them to store power in their cars at times of abundance and feed it into their home or the grid when demand and prices are high.

What’s holding bidi back?

If bidirectionality (bidi) is such a great idea, then why isn’t it happening?

It’s a classic market failure. The main problem is that for most carmakers bidi is just a gimmick. Something to be offered as an expensive option to geeks, not a development priority, and certainly not a cheap standard feature on every electric car.

On the charging side, there is more interest, but as long as there are no vehicles, there’s no business case for heavy investment in bidi chargers. Without volume, costs remain high. Costing more than €4,000 each, the few chargers that exist are expensive, and might not be interoperable with other cars – killing the business case for consumers.

Finally, grid operators can be quite conservative, making life hard for both businesses and consumers that want to use cars as mobile storage devices.

Making the batteries on wheels dream reality

There are already millions of batteries on wheels on our streets. By 2035 every new car and van sold will have a battery. Grids and flexibility are a key part of making sure the transition goes smoothly.

Instead of wasting money subsidising powerwalls for homeowners, lawmakers should give people the legal right to use their cars as home batteries.

Many countries allow people to sell solar power back to the grid. That should be possible for vehicle batteries too. Smart tariffs where consumers pay more during peak hours would boost the bidi business case. The EU needs to do more to promote smart and dynamic tariffs. It should also ban double taxation for EVs that provide flexibility services to the grid.

The EU has a big role to play as a standard setter. Specifications for bidirectional chargers should be harmonised, avoiding situations where manufacturers have to design different products for different European markets, and preventing situations where chargers are not interoperable between EV types.

But all of this is pointless without bidirectional vehicles. From a hardware perspective this is a pretty simple and low-cost proposition. The EU should set a goal for that to become standard from 2030 onwards – something that is missing from its action plan.

Motorists want bidirectional charging, our grids need it, but car manufacturers aren’t delivering. If we don’t start to act soon, the storage potential of hundreds of millions of EVs will remain untapped. It’s time for the Commission to set a clear goal giving every European the ability to fully utilise their “battery on wheels”.