HUNDREDS OF CHARGING stations for electric vehicles dot Utrecht’s urban landscape in the Netherlands like little electric mushrooms. Unlike those you may have grown accustomed to seeing, many of these stations don’t just charge electric cars—they can also send power from vehicle batteries to the local utility grid for use by homes and businesses.

Debates over the feasibility and value of such vehicle-to-grid technology go back decades. Those arguments are not yet settled. But big automakers like Volkswagen, Nissan, and Hyundai have moved to produce the kinds of cars that can use such bidirectional chargers—alongside similar vehicle-to-home technology, whereby your car can power your house, say, during a blackout, as promoted by Ford with its new F-150 Lightning. Given the rapid uptake of electric vehicles, many people are thinking hard about how to make the best use of all that rolling battery power.

Utrecht, a largely bicycle-propelled city of 350,000 just south of Amsterdam, has become a proving ground for the bidirectional-charging techniques that have the rapt interest of automakers, engineers, city managers, and power utilities the world over. This initiative is taking place in an environment where everyday citizens want to travel without causing emissions and are increasingly aware of the value of renewables and energy security.

“We wanted to change,” says Eelco Eerenberg, one of Utrecht’s deputy mayors and alderman for development, education, and public health. And part of the change involves extending the city’s EV-charging network. “We want to predict where we need to build the next electric charging station.”

So it’s a good moment to consider where vehicle-to-grid concepts first emerged and to see in Utrecht how far they’ve come.

It’s been 25 years since University of Delaware energy and environmental expert Willett Kempton and Green Mountain College energy economist Steve Letendre outlined what they saw as a “dawning interaction between electric-drive vehicles and the electric supply system.” This duo, alongside Timothy Lipman of the University of California, Berkeley, and Alec Brooks of AC Propulsion, laid the foundation for vehicle-to-grid power.

The inverter converts alternating current to direct current when charging the vehicle and back the other way when sending power into the grid. This is good for the grid. It’s yet to be shown clearly why that’s good for the driver.

Their initial idea was that garaged vehicles would have a two-way computer-controlled connection to the electric grid, which could receive power from the vehicle as well as provide power to it. Kempton and Letendre’s 1997 paper in the journal Transportation Research describes how battery power from EVs in people’s homes would feed the grid during a utility emergency or blackout. With on-street chargers, you wouldn’t even need the house.

Bidirectional charging uses an inverter about the size of a breadbasket, located either in a dedicated charging box or onboard the car. The inverter converts alternating current to direct current when charging the vehicle and back the other way when sending power into the grid. This is good for the grid. It’s yet to be shown clearly why that’s good for the driver.

This is a vexing question. Car owners can earn some money by giving a little energy back to the grid at opportune times, or can save on their power bills, or can indirectly subsidize operation of their cars this way. But from the time Kempton and Letendre outlined the concept, potential users also feared losing money, through battery wear and tear. That is, would cycling the battery more than necessary prematurely degrade the very heart of the car? Those lingering questions made it unclear whether vehicle-to-grid technologies would ever catch on.

Market watchers have seen a parade of “just about there” moments for vehicle-to-grid technology. In the United States in 2011, the University of Delaware and the New Jersey–based utility NRG Energy signed a technology-license deal for the first commercial deployment of vehicle-to-grid technology. Their research partnership ran for four years.

In recent years, there’s been an uptick in these pilot projects across Europe and the United States, as well as in China, Japan, and South Korea. In the United Kingdom, experiments are now taking place in suburban homes, using outside wall-mounted chargers metered to give credit to vehicle owners on their utility bills in exchange for uploading battery juice during peak hours. Other trials include commercial auto fleets, a set of utility vans in Copenhagen, two electric school buses in Illinois, and five in New York.

These pilot programs have remained just that, though—pilots. None evolved into a large-scale system. That could change soon. Concerns about battery wear and tear are abating. Last year, Heta Gandhi and Andrew White of the University of Rochestermodeled vehicle-to-grid economics and found battery-degradation costs to be minimal. Gandhi and White also noted that battery capital costs have gone down markedly over time, falling from well over US $1,000 per kilowatt-hour in 2010 to about $140 in 2020.

As vehicle-to-grid technology becomes feasible, Utrecht is one of the first places to fully embrace it.

The key force behind the changes taking place in this windswept Dutch city is not a global market trend or the maturity of the engineering solutions. It’s having motivated people who are also in the right place at the right time.

One is Robin Berg, who started a company called We Drive Solar from his Utrecht home in 2016. It has evolved into a car-sharing fleet operator with 225 electric vehicles of various makes and models—mostly Renault Zoes, but also Tesla Model 3s, Hyundai Konas, and Hyundai Ioniq 5s. Drawing in partners along the way, Berg has plotted ways to bring bidirectional charging to the We Drive Solar fleet. His company now has 27 vehicles with bidirectional capabilities, with another 150 expected to be added in coming months.