Your Tesla could make your toast. Why doesn’t it?

One of the most important technologies for a clean power grid is sitting idle in your garage.

That’s because electric cars aren’t just vehicles — they’re batteries as well. Unlocking their full potential could speed the integration of more wind and solar into the world’s electricity networks. Petty regulations, corporate timidity, and a shortage of key components are holding that back.

Tesla’s problems are not about supply. It’s demand.Credit: AP

Consider the example of California. The 7.3 gigawatts of huge, utility-scale batteries that energy companies have been adding in recent years have started nudging aside gas, traditionally the source of energy that was easiest to switch on and off during the grid’s daily peaks and troughs.

In the past, gas switched on en masse as the sun set and solar generation dwindled to nothing. This year it’s been running at something like half its previous levels. That appears to be because batteries are charging up on dirt-cheap midday solar power and discharging in the evening when electricity is most profitable — removing the need to switch on gas turbines.

What’s most remarkable is that all this has been achieved without tapping the state’s biggest resource of battery storage — electric cars. California’s 1.5 million EVs can provide roughly three times as much energy as its utility-scale batteries, but despite years of study the prospects of turning them into backup for the power network still seem remote.

EVs charged during the day, when solar energy is being given away, could make money for their owners by discharging into the grid when prices soar after dark

That’s a terrible waste. More than 90 per cent of the 2400 gigawatt-hours of rechargeable batteries in use globally are in electric vehicles, according to the International Energy Agency. With solar and wind long having undercut fossil fuels on cost, the biggest decarbonisation challenge in the coming decade is not generating sufficient clean energy, but providing it at the right time — particularly the peak between 6 pm and 9 pm, when the sun has set, commuter cars are parked, and household demand is strongest.

Millions of EVs charged during the day, when solar energy is being given away, could make money for their owners by discharging into the grid when prices soar after dark. No one would want their car battery to run flat just to power their neighbour’s television or air conditioner — but smart technology allowing owners to offer (say) 20 per cent of a full battery in return for a pay cheque from the power company could be an attractive way of balancing a volatile grid.

There’s no major fundamental reason this isn’t happening. Rather, it’s a mix of small-scale hurdles.

Consider the various participants in a potential vehicle-to-grid, or V2G market. Utilities are generally in favour of technologies that help them avoid blackouts, but cars aren’t a great substitute for dedicated, grid-connected batteries. Trying to predict the behaviour of owners — whether they’re home, whether they’ve plugged their car in, and whether they’ve set discharging limits so that they’ve got enough juice for a long intercity journey tomorrow — adds a whole new layer of complexity to the picture. As a result, they’re unlikely to pay as much for V2G electricity as they’d give to a standalone battery farm.

Carmakers are similarly reluctant. With the EV market still in its infancy, battery degradation is a worry to many buyers. Automakers are assuaging those fears with warranties that typically run for eight to 10 years, but a battery that is recharging and discharging every day to power the grid will probably run down faster than one in more normal usage. In that situation, the owner’s V2G profit becomes the carmaker’s warranty liability — an alarming prospect given all the money manufacturers are already spending on the switch to electric.

Some car companies have embraced a related way of using your battery — vehicle-to-home or V2H discharging, which powers just your own appliances, and causes less wear of your power cells. The shift has been halting and piecemeal, nonetheless: General Motors is in the process of rolling it out, but Ford will only do it with dedicated, and costly, charging stations. Meanwhile, Tesla chief executive officer Elon Musk has been a notable sceptic, though the company is reportedly planning to introduce the technology next year.

Even individuals seem lukewarm on the idea. Cars are idle 95 per cent of the time. Using them as batteries when they’re parked seems the perfect way of paying off that car loan — but the relatively modest uptake of things like car-sharing and widespread indifference to depreciation costs suggests that owners aren’t all that interested in maximising the returns on their investments.

A really valuable payment from the grid for a limited discharge that doesn’t mess with your daily commute would be the perfect thing to whet the public’s appetite. That sort of generous payment with robust consumer guardrails, however, is likely to prove less attractive to utilities. They’d rather deal with a dedicated battery farm than count on an unruly flock of householders being plugged in at the right time.

All of this represents a tragic failure to exploit the clean-energy assets we have in an efficient way. While the world as a whole would benefit greatly from a wide-scale shift to V2G, most players would see only marginal advantages, or even disadvantages. If governments don’t intervene to break this deadlock, the current wasteful stagnation will persist.

David Fickling is a Bloomberg Opinion columnist covering climate change and energy. Previously, he worked for Bloomberg News, the Wall Street Journal and the Financial Times.

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