march18

Special Report: Fukushima and the Future of Nuclear Power

Editor's Note: John Boyd is an IEEE Spectrum contributor reporting from Kawasaki, Japan. This is part of IEEE Spectrum's ongoing coverage of Japan's earthquake and nuclear emergency. For more details on how Fukushima Dai-1's nuclear reactors work and what has gone wrong so far, see our explainer and our timeline.

One week after the devastating 9.0 magnitude earthquake hit northeast Japan, authorities further raised their efforts to get Japan’s damaged Fukushima Dai-1 nuclear power plant under control today. Thirty squads of fire fighters from Tokyo arrived in Iwaki, a small town south of the plant, and prepared to help the country’s Self-Defense Force (SDF), which has been discharging water into the critical reactor No. 3 building. At the same time Tokyo Electric Power Co. (TEPCO) repair crews were working to bringing power to the site from grid lines despite dangerous radiation conditions.

Minister of Defense Toshimi Kitazawa told reporters that there would be “no helicopter water drops conducted today," which suggests yesterday’s four water drops over the reactors were ineffective or perhaps too dangerous to continue with for a second day. But he said that SDF groups would resume their efforts from yesterday evening and use water cannon trucks to jet water into the No. 3 reactor building. The aim is to refill the spent fuel storage pool, which contains hundreds of spent fuel rods.

The pool has been losing water through evaporation. White steam was seen billowing from the building Wednesday morning and continued to be emitted Thursday and Friday, indicating that the water was boiling away. Parts of the fuel rods may therefore be exposed to air. That exposure would cause the still-radioactive spent fuel to heat further and could cause it to begin melting, which would create a major source of radiation leakage. The temperatures in the storage pools of No. 4, 5 and 6 have also reportedly been heating up, but according to TEPCO and Japanese officials they have not so far become as critical as the situation at No. 3.

(Contradictory reports continue to come from U.S. nuclear engineers and officials regarding the No. 4 building's storage pools. Yesterday the head of the U.S. Nuclear Regulatory Commission declared that pool empty of water, and today the Los Angeles Times reported that the wall or floor of the 45-foot-deep pool may have a crack or breach. If true, that would make it more difficult to keep water over the spent fuel rods in the No. 4 pool.)

Meanwhile, at a press conference around 10 a.m. Friday TEPCO officials said that repair crews had laid a 930-meter cable from the electricity grid and were making preparations to connect it to a temporary distribution panel. From that panel they would connect power to the No. 2 reactor building transformer and later the No. 1 reactor building transformer. Since last Friday's earthquake and tsunami, the power plant has been relying on backup generators and batteries.

More than 320 TEPCO workers are now battling to stabilize the plant in various ways, including some 50 workers who are working close to the plant, apparently on a daily basis.

In some ways, experts say, the No. 2 reactor to be in a more critical condition than the troubled storage pool of the No. 3 reactor. An earlier explosion in the No. 2 reactor building is believed to have caused damage to the reactor’s suppression pool. The suppression pool (also called the torus) is connected to the primary containment vessel, the structure that protects the chamber where nuclear fission takes place. TEPCO has reported that the pressure inside the reactor had dropped, suggesting that the primary containment vessel may have been damaged by the accident at the suppression pool. That could mean that radioactive material is leaking from the primary containment vessel.

But experts point out that there's another line of protection--the secondary containment building, which does not appear to be damaged. “The situation with No. 2 is not good either, but the building has a roof,” Kazuaki Matsui, executive managing director of the Institute of Applied Energy, an independent organization in Tokyo, told Spectrum. “There may be a hole or damage in the suppression chamber and there could be some radiation leakage from the water there. But as long as it stays in the building, then it can be fixed later.”

This is not the case with the No. 3 building, which is badly damaged. “No. 1 and No. 3 (buildings) don’t have roofs,” says Matsui. “So if (exposed spent fuel) emits radioactive materials, then this is a more tense situation.”

NHK, Japan’s national broadcaster, showed live footage of water being jetted into the No. 3 building starting from 1:55 p.m local time on Friday. The footage was taken from a helicopter positioned over 30 kilometers west of the plant looking towards the Pacific Ocean. When the operation began, white steam almost immediately billowed upwards from the building, indicating that water was entering the troubled storage pool.

While the vehicles weren’t observable, it was later confirmed that the SDF mounted the operation. The plan was to shoot 45 metric tons of water into the building using six fire trucks. This was in addition to the 27 metric tons the SDF injected into the same building yesterday evening. One truck at a time was used and the operation was temporally halted after three trucks discharged their loads, then it resumed again later for total of six discharges. NHK later reported that TEPCO workers also took part using a seventh fire truck borrowed from the U.S. military.

Yukio Edano, Japan's chief cabinet secretary, said in a later press conference he was sure the operation had achieved some success because “of the steam coming from the building afterwards.”

At 5:30 p.m. local time five Tokyo firefighting trucks left their base in Iwaki and began making their way to the plant, on a mission to inject water into the No. 1 building. As of 8:30 p.m. no word had come whether or not they had begun the operation. NHK reported that TEPCO repair crews were being hampered by radiation close to plant, and said the company was now hoping to bring power to the No. 2 reactor building and get cooling systems operating again by Saturday.

Prime Minister Naoto Kan addressed the nation in an evening broadcast and commented on the Fukushima plant, saying, “The situation surrounding the accident is still very grave. To overcome this crisis, the police, fire fighters, Self-Defense forces and other groups are all working together, putting their lives on the line in an attempt to solve the situation.”
 

Photo: TEPCO

The Conversation (0)
This photograph shows a car with the words “We Drive Solar” on the door, connected to a charging station. A windmill can be seen in the background.

The Dutch city of Utrecht is embracing vehicle-to-grid technology, an example of which is shown here—an EV connected to a bidirectional charger. The historic Rijn en Zon windmill provides a fitting background for this scene.

We Drive Solar

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.

The number of charging stations in Utrecht has risen sharply over the past decade.

“People are buying more and more electric cars,” says Eerenberg, the alderman. City officials noticed a surge in such purchases in recent years, only to hear complaints from Utrechters that they then had to go through a long application process to have a charger installed where they could use it. Eerenberg, a computer scientist by training, is still working to unwind these knots. He realizes that the city has to go faster if it is to meet the Dutch government’s mandate for all new cars to be zero-emission in eight years.

The amount of energy being used to charge EVs in Utrecht has skyrocketed in recent years.

Although similar mandates to put more zero-emission vehicles on the road in New York and California failed in the past, the pressure for vehicle electrification is higher now. And Utrecht city officials want to get ahead of demand for greener transportation solutions. This is a city that just built a central underground parking garage for 12,500 bicycles and spent years digging up a freeway that ran through the center of town, replacing it with a canal in the name of clean air and healthy urban living.

A driving force in shaping these changes is Matthijs Kok, the city’s energy-transition manager. He took me on a tour—by bicycle, naturally—of Utrecht’s new green infrastructure, pointing to some recent additions, like a stationary battery designed to store solar energy from the many panels slated for installation at a local public housing development.

This map of Utrecht shows the city’s EV-charging infrastructure. Orange dots are the locations of existing charging stations; red dots denote charging stations under development. Green dots are possible sites for future charging stations.

“This is why we all do it,” Kok says, stepping away from his propped-up bike and pointing to a brick shed that houses a 400-kilowatt transformer. These transformers are the final link in the chain that runs from the power-generating plant to high-tension wires to medium-voltage substations to low-voltage transformers to people’s kitchens.

There are thousands of these transformers in a typical city. But if too many electric cars in one area need charging, transformers like this can easily become overloaded. Bidirectional charging promises to ease such problems.

Kok works with others in city government to compile data and create maps, dividing the city into neighborhoods. Each one is annotated with data on population, types of households, vehicles, and other data. Together with a contracted data-science group, and with input from ordinary citizens, they developed a policy-driven algorithm to help pick the best locations for new charging stations. The city also included incentives for deploying bidirectional chargers in its 10-year contracts with vehicle charge-station operators. So, in these chargers went.

Experts expect bidirectional charging to work particularly well for vehicles that are part of a fleet whose movements are predictable. In such cases, an operator can readily program when to charge and discharge a car’s battery.

We Drive Solar earns credit by sending battery power from its fleet to the local grid during times of peak demand and charges the cars’ batteries back up during off-peak hours. If it does that well, drivers don’t lose any range they might need when they pick up their cars. And these daily energy trades help to keep prices down for subscribers.

Encouraging car-sharing schemes like We Drive Solar appeals to Utrecht officials because of the struggle with parking—a chronic ailment common to most growing cities. A huge construction site near the Utrecht city center will soon add 10,000 new apartments. Additional housing is welcome, but 10,000 additional cars would not be. Planners want the ratio to be more like one car for every 10 households—and the amount of dedicated public parking in the new neighborhoods will reflect that goal.

This photograph shows four parked vehicles, each with the words \u201cWe Drive Solar\u201d prominently displayed, and each plugged into a charge point.Some of the cars available from We Drive Solar, including these Hyundai Ioniq 5s, are capable of bidirectional charging.We Drive Solar

Projections for the large-scale electrification of transportation in Europe are daunting. According to a Eurelectric/Deloitte report, there could be 50 million to 70 million electric vehicles in Europe by 2030, requiring several million new charging points, bidirectional or otherwise. Power-distribution grids will need hundreds of billions of euros in investment to support these new stations.

The morning before Eerenberg sat down with me at city hall to explain Utrecht’s charge-station planning algorithm, war broke out in Ukraine. Energy prices now strain many households to the breaking point. Gasoline has reached $6 a gallon (if not more) in some places in the United States. In Germany in mid-June, the driver of a modest VW Golf had to pay about €100 (more than $100) to fill the tank. In the U.K., utility bills shot up on average by more than 50 percent on the first of April.

The war upended energy policies across the European continent and around the world, focusing people’s attention on energy independence and security, and reinforcing policies already in motion, such as the creation of emission-free zones in city centers and the replacement of conventional cars with electric ones. How best to bring about the needed changes is often unclear, but modeling can help.

Nico Brinkel, who is working on his doctorate in Wilfried van Sark’s photovoltaics-integration lab at Utrecht University, focuses his models at the local level. In his calculations, he figures that, in and around Utrecht, low-voltage grid reinforcements cost about €17,000 per transformer and about €100,000 per kilometer of replacement cable. “If we are moving to a fully electrical system, if we’re adding a lot of wind energy, a lot of solar, a lot of heat pumps, a lot of electric vehicles…,” his voice trails off. “Our grid was not designed for this.”

But the electrical infrastructure will have to keep up. One of Brinkel’s studies suggests that if a good fraction of the EV chargers are bidirectional, such costs could be spread out in a more manageable way. “Ideally, I think it would be best if all of the new chargers were bidirectional,” he says. “The extra costs are not that high.”

Berg doesn’t need convincing. He has been thinking about what bidirectional charging offers the whole of the Netherlands. He figures that 1.5 million EVs with bidirectional capabilities—in a country of 8 million cars—would balance the national grid. “You could do anything with renewable energy then,” he says.

Seeing that his country is starting with just hundreds of cars capable of bidirectional charging, 1.5 million is a big number. But one day, the Dutch might actually get there.

This article appears in the August 2022 print issue as “A Road Test for Vehicle-to-Grid Tech.”

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