How battery-swap networks are preventing emergency blackouts
On the morning of April 3, Taiwan was hit by a 7.4 magnitude earthquake. Seconds later, hundreds of battery-swap stations in Taiwan sensed something else: the power frequency of the electric grid took a sudden drop, a signal that some power plants had been disconnected in the disaster. The grid was now struggling to meet energy demand.
These stations, built by the Taiwanese company Gogoro for electric-powered two-wheeled vehicles like scooters, mopeds, and bikes, reacted immediately. According to numbers provided by the company, 590 Gogoro battery-swap locations (some of which have more than one swap station) stopped drawing electricity from the grid, lowering local demand by a total six megawatts—enough to power thousands of homes. It took 12 minutes for the grid to recover, and the battery-swap stations then resumed normal operation.
Gogoro is not the only company working on battery-swapping for electric scooters (New York City recently launched a pilot program to give delivery drivers the option to charge this way), but it’s certainly one of the most successful. Founded in 2011, the firm has a network of over 12,500 stations across Taiwan and boasts over 600,000 monthly subscribers who pay to swap batteries in and out when required. Each station is roughly the size of two vending machines and can hold around 30 scooter batteries.
Now the company is putting the battery network to another use: Gogoro has been working with Enel X, an Italian company, to incorporate the stations into a virtual power plant (VPP) system that helps the Taiwanese grid stay more resilient in emergencies like April’s earthquake.
Battery-swap stations work well for VPP programs because they offer so much more flexibility than charging at home, where an electric-bike owner usually has just one or two batteries and thus must charge immediately after one runs out. With dozens of batteries in a single station as a demand buffer, Gogoro can choose when it charges them—for instance, doing so at night when there’s less power demand and it’s cheaper. In the meantime, the batteries can give power back to the grid when it is stressed—hence the comparison to power plants.
“What is beautiful is that the stations’ economic interest is aligned with the grid—the [battery-swap companies] have the incentive to time their charges during the low utilization period, paying the low electricity price, while feeding electricity back to the grid during peak period, enjoying a higher price,” says S. Alex Yang, a professor of management science at London Business School.
Gogoro is uniquely positioned to become a vital part of the VPP network because “there’s a constant load in energy, and then at the same time, we’re on standby that we can either stop taking or giving back [power] to the grid to provide stability,” Horace Luke, cofounder and CEO of Gogoro, tells MIT Technology Review.
Luke estimates that only 10% of Gogoro batteries are actually on the road powering scooters at any given time, so the rest, sitting on the racks waiting for customers to pick up, become a valuable resource that can be utilized by the grid.
Today, out of the 2,500 Gogoro locations, over 1,000 are part of the VPP program. Gogoro promises that the system will automatically detect emergencies and, in response, immediately lower its consumption by a certain total amount.
Which stations get included in the VPP depends on where they are and how much capacity they have. A smaller station right outside a metro stop—meaning high demand and low supply—probably can’t afford to stop charging during an emergency because riders could come looking for a battery soon. But a megastation with 120 batteries in a residential area is probably safe to stop charging batteries for a while.
Plus, the entire station doesn’t go dark—Gogoro has a built-in system that decides which or how many batteries in a station stop charging. “We know exactly which batteries to spin down, which station to spin down, how much to spin down,” says Luke. “That was all calculated in real time in the back side of the server.” It can even consolidate the power left in several batteries into one, so a customer who comes in can still leave with a fully charged battery even if the whole system is operating below capacity.
The earthquake and its aftermath in Taiwan this year put the VPP stations to the test—but also showed the system’s strength. On April 15, 12 days after the initial earthquake, the grid in Taiwan was still recovering from the damage when another power drop happened. This time, 818 Gogoro locations reacted in five seconds, reducing power consumption by 11 megawatts for 30 minutes.
Numbers like 6 MW and 11 MW are “not a trivial amount of power but still substantially smaller than a centralized power plant,” says Joshua Pearce, an engineering professor at Western University in Ontario, Canada. For comparison, Taiwan lost 3,200 MW of power supply right after the April earthquake, and the gap was mostly filled by solar power, centralized battery storage, and hydropower. But the entire Taiwanese VPP network combined, which has reached a capacity of 1,350 MW, can make a significant difference. “It helps the grid maintain stability during disasters. The more smart loads there are on the grid, the more resilient it is,” he says.
However, the potential of these battery-swap stations has not been fully achieved yet; the majority of the stations have not started giving energy back to the grid.
“The tech system is ready, but the business and economics are not ready,” Luke says. There are 10 Gogoro battery-swapping stations that can return electricity to the grid in a pilot program, but other stations haven’t received the technological update.
Upgrading stations to bi-directional charging makes economic sense only if Gogoro can profit from selling the electricity back. While the Taiwanese state-owned utility company currently allows private energy generators like solar farms to sell electricity to the grid at a premium, it hasn’t allowed battery-storage companies like Gogoro to do so.
This challenge is not unique to Taiwan. Incorporating technologies like VPP requires making fundamental changes to the grid, which won’t happen without policy support. “The technology is there, but the practices are being held back by antiquated utility business models where they provide all electric services,” says Pearce. “Fair policies are needed to allow solar energy and battery owners to participate in the electric market for the best interest of all electricity consumers.”
