A maze of brackish and freshwater ponds covers Taiwan’s coastal plain, supporting aquaculture operations that produce roughly NT $30 billion (US $920 million) worth of seafood every year. Taiwan’s government is hoping that the more than 400 square kilometers of fishponds can simultaneously produce a second harvest: solar power.

What is aquavoltaics?

That’s the impetus behind the new 42.9-megawatt aquavoltaics facility in the southern city of Tainan. To build it, Taipei-based Hongde Renewable Energy bought 57.6 hectares of abandoned land in Tainan’s fishpond-rich Qigu district, created earthen berms to delineate the two dozen ponds, and installed solar panels along the berms and over six reservoir ponds.

Tony Chang, general manager of the Hongde subsidiary Star Aquaculture, says 18 of the ponds are stocked with mullet (prized for their roe) and shrimp, while milkfish help clean the water in the reservoir ponds. In 2023, the first full year of operation, Chang says his team harvested over 100,000 kilograms of seafood. This August, they began stocking a cavernous indoor facility, also festooned with photovoltaics, to cultivate white-legged shrimp.

A number of other countries have been experimenting with aquavoltaics, including China, Chile, Bangladesh, and Norway, extending the concept to large solar arrays floating on rivers and bays. But nowhere else is the pairing of aquaculture and solar power seen as so crucial to the economy. Taiwan is striving to massively expand renewable generation to sustain its semiconductor fabs, and solar is expected to play a large role. But on this densely populated island—slightly larger than Maryland, smaller than the Netherlands—there’s not a lot of open space to install solar panels. The fishponds are hard to ignore. By the end of 2025, the government is looking to install 4.4 gigawatts of aquavoltaics to help meet its goal of 20 GW of solar generation.

Is Taiwan’s aquavoltaics plan unrealistic?

Meanwhile, though, solar developers are struggling to deliver on Taiwan’s ambitious goals, even as some projections suggest Taiwan will need over eight times more solar by 2050. And aquavoltaics in particular have come under scrutiny from environmental groups. In 2020, for example, reporter Cai Jiashan visited 100 solar plants built on agricultural land, including fishponds, and found dozens of cases where solar developers built more solar capacity than the law intended, or secured permits based on promises of continued farming that weren’t kept.

Star Aquaculture grows milkfish to help clean water for its breeding ponds.HDRenewables

On 7 July 2020, Taiwan’s Ministry of Agriculture responded by restricting solar development on farmland, in what the solar industry called the “Double-Seven Incident.” Many aquavoltaic projects were canceled while others were delayed. The latter included a 10-MW facility in Tainan that Google had announced to great fanfare in 2019 as its first renewable-energy investment in Asia, to supply power for the company’s Taiwan data centers. The array finally started up in 2023, three years behind schedule.

Critics of Taiwan’s renewed aquavoltaic plans thus see the government’s goal as unrealistic. Yuping Chen, executive director of the Taiwan Environment and Planning Association, a Taipei-based nonprofit dedicated to resolving conflicts between solar energy and agriculture, says of aquavoltaics, “It is claimed to be crucial by the government, but it’s impossible to realize.”

How aquavoltaics could revive fishing, boost revenue

Solar developers and government officials who endorse aquavoltaics argue that such projects could revive the island’s traditional fishing community. Taiwan’s fishing villages are aging and shrinking as younger people take city jobs. Climate change has also taken a toll. Severe storms damage fishpond embankments, while extreme heat and rainfall stress the fish.

4.4

Gigawatts of aquavoltaics that Taiwan wants to install by the end of 2025

Solar development could help reverse these trends. Several recent studies examining fishponds in Taiwan found that adding solar improves profitability, providing an opportunity to reinvigorate communities if agrivoltaic investors share their returns. Alan Wu, deputy director of the Green Energy Initiative at Taiwan’s Industrial Technology Research Institute, says the Hsinchu-based lab has opened a research station in Tainan to connect solar and aquaculture firms. ITRI is helping aquavoltaics facilities boost their revenues by figuring out how they can raise “species of high economic value that are normally more difficult to raise,” Wu says.

Such high-value products include the 27,000 pieces of sun-dried mullet roe that Hongde Renewable Energy’s Tainan site produced last year. The new indoor facility, meanwhile, should boost yields of the relatively pricey whiteleg shrimp. Chang expects the indoor harvests to fetch $500,000 to $600,000 annually, compared to $800,000 to $900,000 from the larger outdoor ponds.

The solar roof over the 100,000-liter indoor growth tanks protects the 2.7 million shrimp against weather and bird droppings. Chang says a patent-pending drain mechanically removes waste from each tank, and also sucks out the shrimp when they’re ready for harvest.

Land that Star Aquaculture set aside for wildlife now attracts endangered birds like the black-faced spoonbill [left] and the oriental stork [right].iStock (2)

The company has also set aside 9 percent of the site for wildlife, in response to concerns from conservationists. “Egrets, endangered oriental storks, and black-faced spoonbills continue to use the site,” Chang says. “If it was all covered with PV, it could impact their habitat.”

Such measures may not satisfy environmentalists, though. In a review published last month, researchers at Fudan University in Shanghai and two Chinese power firms concluded that China’s floating aquavoltaic installations—some of which already span 5 square kilometers—will “inevitably” alter the marine environment.

Aquavoltaic facilities that are entirely indoors may be an even harder sell as they scale up. Toshiba is backing such a plant in Tainan, to generate 120 MW for an unspecified “semiconductor manufacturer,” with plans for a 360-MW expansion. The resulting buildings could exclude wildlife from 5 square kilometers of habitat. Indoor projects could compensate by protecting land elsewhere. But, as Chen of the Taiwan Environment and Planning Association notes, developers of such sites may not take such measures unless they’re required by law to do so.

A French cycling official confronts a rider suspected of doping and ends up jumping onto the hood of a van making a high-speed getaway. This isn’t a tragicomedy starring Gérard Depardieu, sending up the sport’s well-earned reputation for cheating. This scenario played out in May at the Routes de l’Oise cycling competition near Paris, and the van was believed to contain evidence of a distinctly 21st-century cheat: a hidden electric motor.

Cyclists call it “motor doping.” At the Paris Olympics opening on Friday, officials will be deploying electromagnetic scanners and X-ray imaging to combat it, as cyclists race for gold in and around the French capital. The officials’ prey can be quite small: Cycling experts say just 20 or 30 watts of extra power is enough to tilt the field and clinch a race.

Motor doping has been confirmed only once in professional cycling, way back in 2016. And the sport’s governing body, the Union Cycliste Internationale (UCI), has since introduced increasingly sophisticated motor-detection methods. But illicit motors remain a scourge at high-profile amateur events like the Routes de l’Oise. Some top professionals, past and present, continue to raise an alarm.

“It’s 10 years now that we’re speaking about this…. If you want to settle this issue you have to invest.” —Jean-Christophe Péraud, former Union Cycliste Internationale official

Riders and experts reached by IEEE Spectrum say it’s unlikely that technological doping still exists at the professional level. “I’m confident it’s not happening any more. I think as soon as we began to speak about it, it stopped. Because at a high level it’s too dangerous for a team and an athlete,” says Jean-Christophe Péraud, an Olympic silver medalist who was UCI’s first Manager of Equipment and the Fight against Technological Fraud.

But trust is limited. Cycling is still recovering from the scandals surrounding U.S. Olympian Lance Armstrong, whose extensive use of transfusions and drugs to boost blood-oxygen levels fueled allegations of collusion by UCI officials and threats to boot cycling out of the Olympics.

Many—including Péraud—say more vigilance is needed. The solution may be next-generation detection tech: onboard scanners that provide continuous assurance that human muscle alone is powering the sport’s dramatic sprints and climbs.

How Officials Have Hunted for Motor Doping in Cycling

Rumors of hidden motors first swirled into the mainstream in 2010 after a Swiss cyclist clinched several European events with stunning accelerations. At the time the UCI lacked means of detecting concealed motors, and its technical director promised to “speed up” work on a “quick and efficient way” to do so.

The UCI began with infrared cameras, but they are useless for pre- and post-race checks when a hidden motor is cold. Not until 2015, amidst further motor doping rumors and allegations of UCI inaction, did the organization begin beta testing a better tool: an iPad-based “magnetometric tablet” scanner.

According to the UCI, an adapter plugged into one of these tablet scanners creates an ambient magnetic field. Then, a magnetometer and custom software register disruptions to the field that may indicate the presence of metal or magnets in and around a bike’s carbon-fiber frame.

UCI’s tablets delivered in their debut appearance, at the 2016 Cyclocross World Championships held that year in Belgium. Scans of bikes at the rugged event—a blend of road and mountain biking—flagged a bike bearing the name of local favorite Femke Van den Driessche. Closer inspection revealed a motor and battery lodged within the hollow frame element that angles down from a bike’s saddle to its pedals, and wires connecting the seat tube’s hidden hardware to a push-button switch under the handlebars.

In 2016, a concealed motor was found in a bike bearing Belgian cyclist Femke Van Den Driessche’s name at the world cyclo-cross championships. (Van Den Driessche is shown here with a different bike.)AFP/Getty Images

Van den Driessche, banned from competition for six years, withdrew from racing while maintaining her innocence. (Giovambattista Lera, the amateur cyclist implicated earlier this year in France, also denies using electric assistance in competition.)

The motor in Van den Driessche’s bike engaged with the bike’s crankshaft and added 200 W of power. The equipment’s Austrian manufacturer, Vivax Drive, is now defunct. But anyone with cash to spare can experience 200 W of extra push via a racer equipped by Monaco-based HPS-Bike, such as the HPS-equipped Lotus Type 136 racing bike from U.K. sports car producer Lotus Group, which starts at £15,199 (US $19,715).

HPS founder & CEO Harry Gibbings says the company seeks to empower weekend riders who don’t want to struggle up steep hills or who need an extra boost here and there to keep up with the pack. Gibbings says the technology is not available for retrofits, and is thus off limits to would-be cheats. Still, the HPS Watt Assist system shows the outer bounds of what’s possible in discreet high-performance electric assist.

The 30-millimeter-diameter, 300-gram motor, is manufactured by Swiss motor maker Maxon Group, and Gibbings says it uses essentially the same power-dense brushless design that’s propelling NASA’s Perseverance rover on Mars. HPS builds the motor into a bike’s downtube, the frame element angling up from a bike’s crank toward its handlebars.

Notwithstanding persistent media speculation about electric motors built into rear hubs or solid wheels, Gibbings says only a motor placed in a frame’s tubes can add power without jeopardizing the look, feel, and performance of a racing bike.

UCI’s New Techniques to Spot Cheating in Cycling

Professional cycling got its most sophisticated detection systems in 2018, after criticism of UCI motor-doping policies helped fuel a change of leadership. Incoming President David Lappartient appointed Péraud to push detection to new levels, and five months later UCI announced its first X-ray equipment at a press conference in Geneva.

Unlike the tablet scanners, which yield many false positives and require dismantling of suspect bikes, X-ray imaging is definitive. The detector is built into a shielded container and driven to events.

UCI told the cycling press that its X-ray cabinet would “remove any suspicion regarding race results.” And it says it maintains a high level of testing, with close to 1,000 motor-doping checks at last year’s Tour de France.

UCI declined to speak with IEEE Spectrum about its motor-detection program, including plans for the Paris Olympics. But it appears to have stepped up vigilance. Lappartient recently acknowledged that UCI’s controls are “not 100 percent secure” and announced a reward for whistleblowers who deliver evidence of motor fraud. In May, UCI once again appointed a motor-doping czar—a first since Péraud departed amidst budget cuts in 2020. Among other duties, former U.S. Department of Homeland Security criminal investigator Nicholas Raudenski is tasked with “development of new methods to detect technological fraud.”

Unlike the tablet scanners, X-ray imaging is definitive.

Péraud is convinced that only real-time monitoring of bikes throughout major races can prove that motor fraud is in the past, since big races provide ample opportunities to sneak in an additional bike and thus evade UCI’s current tools.

UCI has already laid the groundwork for such live monitoring, partnering with France’s Alternative Energies and Atomic Energy Commission (Commissariat à l’énergie atomique et aux énergies alternatives, or CEA) to capitalize on the national lab’s deep magnetometry expertise. UCI disclosed some details at its 2018 Geneva press conference, where a CEA official presented its concept: an embedded, high-resolution magnetometer to detect a hidden motor’s electromagnetic signature and wirelessly alert officials via receivers on race support vehicles.

As of June 2018, CEA researchers in Grenoble had identified an appropriate magnetometer and were evaluating the electromagnetic noise that could challenge the system—“from rotating wheels and pedals to passing motorcycles and cars.”

Mounting detectors on every bike would not be cheap, but Péraud says he is convinced that cycling needs it: “It’s 10 years now that we’re speaking about this…. If you want to settle this issue you have to invest.”