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.

The 7.1 magnitude aftershock that jolted northeastern Japan at 11:32 Thursday night knocked out electricity grid transformers and transmission lines, leaving more than 4 million households across several prefectures in the region without power at one point (though some of those homes were already without power because of the 11 March earthquake).  In addition, three deaths and some 140 injuries have been reported.

Nevertheless, the crisis-hit Fukushima Dai-1 Nuclear Plant came through the ordeal without any further abnormalities reported. Tokyo Electric Power Co. (TEPCO) withdrew its workers from the plant as a precaution when the Japanese Meteorological Agency issued a tsunami warning, but the warning was lifted one hour and twenty minutes later, and the workers returned to carry out inspection for damage and signs of increased radiation levels. As of Friday evening TEPCO had reported no new problems or signs of increased radiation.

However, the International Atomic Energy Agency (IAEA), citing data supplied by Japan’s Nuclear and Industrial Safety Agency (NISA) said that the quake caused trouble at several other nuclear plants in the troubled northeast area.

  • The Higashidori Nuclear Power Plant, which had been shut down for maintenance at the time of the latest aftershock, temporarily lost its off-site power feeds and was relying on emergency diesel generators to cool the spent fuel storage pool where all the reactor fuel rods were being kept.
  • Tomari Nuclear Power Plant in Hokkaido, Japan’s northernmost island, had reactors Nos. 1 and 2 in operation when the quake struck; generating power has been reduced to 90 percent of capacity.
  • Kyodo News reports that radioactive water spilled from a spent fuel pool at the Onagawa power plant during the quake.
  • The Rokkasho Reprocessing Plant lost outside power and was relying on emergency diesel generators until power from the electric grid could be restored.

At Fukushima, workers continue to inject nitrogen gas into the containment vessel of the No. 1 reactor, according to TEPCO. The company also expects to finish discharging into the ocean today the last 300 of 8000 metric tons of low-level radioactive water from the wastewater treatment facility. The discharge is to make room for pumping in highly radioactive water pooled in the turbine basement and an external trench carrying cables and pipes for reactor No. 2. (The amount had previously been reported as 10 000 metric tons.)

The company will finish discharging a separate 1500 tons of low-level radioactive water from the sub-drainage pits into the ocean on Saturday, to prevent the water from seeping into the buildings of Units 5 and 6 and damaging vital equipment.

Separately, NHK, Japan's national broadcaster, says it has obtained a document showing data recorded at the three damaged reactors on 11 March, the day of the earthquake. TEPCO has so far only provided data beginning from 12 March. NHK says that as of 9:30 p.m. on 11 March, seven hours after the quake, the water level in the No. 1 reactor pressure vessel had fallen precipitously and was only 45 centimeters above the fuel rods, or about one-tenth of the normal volume of water, indicating that its cooling system had already been compromised. By comparison, the water levels in reactors Nos. 2 and 3 were four meters above the fuel rods, suggesting that their emergency cooling systems were still operating.

Professor Naoto Sekimura of the Department of Quantum Engineering and Systems Science at the University of Tokyo told NHK viewers that this loss of cooling water in the No. 1 reactor “must have led to the cladding being damaged, causing it to react with vapor and generate hydrogen gas.” He added that this was the likely reason for the hydrogen explosion the day after the quake. NHK says TEPCO responded to this by saying that the company is still investigating the matter.

Meanwhile, Wolfgang Weiss, chair of the UN Scientific Committee on the Effects of Radiation (UNSCEAR), speaking at a press briefing in Vienna yesterday, described the situation at the Fukushima plant as being worse than the Three Mile Island nuclear accident in the United States in 1979, but less serious than the Chernobyl catastrophe, which occurred in Ukraine when it was still part of the Soviet Union, in 1986.

The International Nuclear and Radiological Event Scale, a worldwide standard for rating radiation accidents, gives the Three Mile Island incident a rating of 5 for “Accident with Wider Consequences.” Chernobyl is rated highest, at 7 for “Major Accident.” Japan’s NISA originally rated the Fukushima nuclear plant accident at level 4, for “Accident with Local Consequences,” but raised this to level 5 mid-March as more problems arose and extended its impact.

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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