Crisis of power outage Behind the scenes of tension March 24, 20:43
The "electric power supply and demand tight warning" issued in the jurisdiction of TEPCO for the first time in Japan.
On Tuesday, March 22, when it was raining cold, the Kanto region was hit by a power crisis.
Inside TEPCO, there was a loud voice saying, "If we keep going like this, there will be a power outage at 8:00 pm."
We will follow the tightrope walking power supply in a document and examine the challenges of stable power supply that are no longer the norm.
(Reporter of the Ministry of Economic Affairs Keisuke Igarashi Nishizono Kouki)
Evening March 18: Not enough electricity
The Tokyo Electric Power Headquarters in Chiyoda-ku, Tokyo, on the evening of March 18 (Friday).
Executives such as President Tomoaki Kobayakawa also attended the emergency meeting held online, and it is said that a tense atmosphere was flowing.
The agenda was the supply and demand of electricity in the jurisdiction after the Golden Week holidays.
On the 22nd (Tuesday) after the holidays, it was forecast that the snow would flutter in the Kanto region as well.
It was expected that the cold would increase heating needs and increase electricity demand.
Under the ever-changing weather forecast, TEPCO will scrutinize demand and strive to secure supply capacity.
If it rains, we can't expect the sunlight to generate the power of 18 large power plants at the maximum.
On March 16, two thermal power plants were shut down due to the impact of the Tohoku region earthquake that observed a seismic intensity of 6 upper.
Furthermore, in January and February, the old thermal power plant in Chiba Prefecture, which was restarted in preparation for tight supply and demand, stopped operating again in March.
I didn't have time to restart it.
The rope of recourse is pumped storage power generation
With neither thermal power nor solar power expected, "pumped storage power generation" was decided to be fully operational at the emergency meeting on the 18th.
Pumped storage power generation is a method of pumping water from a dam or pond to a high place, dropping it to a low place at once, and turning a turbine with that power to generate electricity.
TEPCO has nine pumped storage power generation facilities.
It is necessary to pump water to a high place with the surplus electricity at night.
Before the Great East Japan Earthquake, surplus electricity from nuclear power plants was used, but now electricity such as coal-fired power is being used.
This pumped storage power generation was the only facility in TEPCO that could generate electricity immediately, despite the poor power supply capacity.
Water pumping completed by 7:00 am on the 22nd
By 7:00 am on the 22nd, we pumped water into eight pumped-storage power generation facilities, except for one that was under inspection, and secured the amount of power generation equivalent to the daily power consumption of 10 million ordinary households.
It was calculated that if we could use it in a well-balanced manner for 15 hours until 10 pm while we could not increase thermal power generation, we would be able to overcome the tight situation.
Watch over the consumption of pumped storage with a strong spit
The weather on the 22nd after the holidays actually got cold from early morning.
The electricity usage rate announced by TEPCO every hour on the hour was 86% at 7:00 am, but it jumped to 95% at 8:00 am.
We will use the water from pumped storage power generation, which can be said to be a tiger cub, at a pace faster than TEPCO expected.
After 10 am: 101% impact
At 10 am, TEPCO announced that the usage rate was 101%.
On the data, the actual demand exceeds the supply capacity.
This is a "deviation" that occurred because the amount of power generated by the pumped storage that was suddenly input was not immediately reflected, but one person concerned revealed that "the supply and demand was actually at the limit."
Around 10:30 am: Tohoku Electric Power also ...
Under these circumstances, shock information will be entered around 10:30 am.
It is said that there is a possibility that a tight warning will be issued due to insufficient power even within the Tohoku Electric Power jurisdiction, which was urgently accommodating power to TEPCO.
Tohoku Electric Power Co., Inc. hastened to stop accommodating to TEPCO and will receive accommodation from Hokkaido Electric Power Company.
Possibility of exhaustion of pumped storage
TEPCO was forced to use more pumped-storage power generation to continue to supply electricity to meet ever-increasing demand.
As of noon, the remaining power generation of pumped storage is 71%.
The target value was 79%, which was 8% more than that.
Even after that, the remaining amount of pumped storage continued to decrease below the target, and it was highly possible that the remaining amount of pumped storage power generation would run out earlier than 10 pm.
Before 3:00 pm: An unusual emergency press conference by the Minister of Economy, Trade and Industry
"About 10 minutes later, the minister will hold an urgent press conference."
Around 2:30 pm, unusual news came to the press club of the Ministry of Economy, Trade and Industry.
The minister's press conference is usually announced at least an hour before the press prepares.
However, the situation was so serious that it was too late to wait for it.
NHK hurriedly broadcast the minister's emergency press conference live on special news.
Before 3:00 pm: Possibility of power outage
"At 8:00 pm, the pumping will run out and there is a risk of a power outage." Just before this press conference, new information was secretly sent.
What will happen to the electric power in the jurisdiction if this is left as it is?
One idea goes through my head.
It is a "rolling blackout".
In 2011, when the Great East Japan Earthquake and the nuclear accident occurred, the supply capacity was expected to decline significantly, so in order to prevent a large-scale power outage, we decided in advance the areas to be cut off and stopped the power supply in order.
However, when interviewing TEPCO and the Agency for Natural Resources and Energy, it was difficult to determine how much supply capacity would be insufficient this time, and it was said that there was not enough time to carry out rolling blackouts.
This is because there are a huge number of things to consider when making a plan, such as excluding medical institutions that do not have private power generation facilities and facilities that interfere with daily life in order to implement rolling blackouts.
Possible scenarios
A possible scenario was an automatic power outage due to lack of power.
Electricity has the property that the frequency is disturbed if supply and demand do not match.
If the frequency continues to be disturbed, in the worst case, it can cause a "blackout" that causes the entire area to lose power.
To prevent this, when there is not enough electricity, a function called UFR = frequency drop relay that intentionally cuts off the power supply in some areas is activated, causing a power outage.
At this time, which area will be out of power is randomly determined by the TEPCO system because it is determined mechanically, and cannot be predicted.
This mechanism worked even when a maximum of 2.1 million households in the TEPCO jurisdiction had a power outage due to the earthquake on the 16th.
6:00 pm: Crisis avoided
The government and TEPCO have requested a further step in power saving, especially between 3 pm and 8 pm.
In response to this, efforts to save electricity have expanded not only in households but also in manufacturing industries that use a lot of electricity, retail stores such as department stores and supermarkets, and a wide range of industries.
The amount of power generated by pumped storage exceeded the target of 40%, which was the target of 38% remaining at 6:00 pm, and the goal was to avoid this power crisis.
The issues have come to light again
The various structural issues surrounding electric power have emerged again due to the tightness of electric power.
With the spread of renewable energy, especially solar power generation, toward decarbonization, old thermal power generation, whose operating rate is declining for electric power companies, is not profitable, and there is a growing movement to suspend or abolish it.
The Ministry of Economy, Trade and Industry has submitted a bill to the current Diet that requires prior notification when abolishing an aging thermal power plant as a measure of poverty.
To make it easier to forecast the supply capacity, and if the supply and demand is tight, request the electric power company to temporarily wait for the abolition.
The policy is to cover the cost with taxes.
It is an extremely distorted structure in which old thermal power must be retained during the decarbonization era.
Regarding nuclear power generation, the government plans to utilize it only when it is recognized that it complies with the new regulatory standards of the Nuclear Regulation Authority.
However, there is a strong public opposition to the utilization of nuclear power plants, and TEPCO has a series of deficiencies in anti-terrorism measures at the Kashiwazaki-Kariwa Nuclear Power Station, so there is no sign of restarting.
Weaknesses in the power grid
In addition, the weaknesses of the power grid have been highlighted.
This time, TEPCO received accommodation from 7 major electric power companies after 7:00 am and from 5 companies after 4:00 pm, but the accommodation from western Japan, which had a margin in supply and demand, was limited. ..
The frequency of electricity is different between western Japan and eastern Japan, and it is necessary to change the frequency with conversion equipment.
Rolling blackouts were implemented in the 2011 Great East Japan Earthquake and the nuclear accident, and the vulnerability of the power grid became a problem. It was enhanced.
However, 1.2 million kW of the 2.1 million kW capacity was already in use, and 300,000 kW was combined with inspection work, so the emergency capacity was limited to a maximum of 600,000 kW.
On the other hand, from Hokkaido to Honshu, a transmission line that runs through the seabed of the Tsugaru Strait is used, but the capacity is 900,000 kW.
It is weaker than the interconnection lines connecting to other areas.
The government plans to increase the capacity of the interconnection line connecting western and eastern Japan to 3 million kW by five years.
Professor Toshihiro Matsumura of the Institute of Social Science, the University of Tokyo, who has been examining Japan's energy policy for many years, said:
Professor Matsumura, Institute of Social Science, The University of Tokyo
"At least the interconnection lines that are planned to be expanded are essential for stable power supply, and should have been developed at an earlier stage."
On the other hand, further development of the power grid needs to be carefully considered.
Professor Matsumura, Institute of Social Science , The University of Tokyo
"To establish a supply system that will not be affected even in an emergency, such as the shutdown of multiple power plants, enormous social costs will be required, and how much investment should be made? I need to think about it. "
Focus on demand rather than supply
The power crisis in Japan has once again highlighted that there are various restrictions and issues in Japan's power supply.
Having a variety of power sources is a very important issue, but it is difficult to come up with a solution just by looking at the power supply aspect.
One hint for thinking about the future is the active cooperation of households and businesses to save electricity.
It is bright that suppressing demand has led to such an improvement in supply and demand.
"Negawatt trading" is attracting attention among experts.
The power company pays the person who saves electricity, based on the idea that the surplus electricity is generated by saving electricity at the peak of electricity.
The system started in 2017 in Japan with the idea of adjusting power supply and demand by making power saving a business rather than good intentions and introducing market principles.
Disseminating such a mechanism should help create an environment where electricity can be used stably.
In this situation, it has become clear that it is not natural for electricity to be supplied in a stable manner.
What kind of power supply should be balanced and how, and is it not possible to try new initiatives from the demand side?
We reaffirmed the importance of what we, as users, think of as our own electricity, rather than relying on the state or the power company.
Keisuke Igarashi ,
Reporter of the Ministry of Economic Affairs
Joined in 2012
After working at the Yokohama Bureau, Akita Bureau, and Sapporo Bureau, the Ministry of Economic Affairs
is currently in charge of the energy industry.
Reporter of the Ministry of Economy
Nishizono Kouki
Joined the Bureau in 2014
After working at the Oita Bureau, the Ministry of Economy is
currently
in charge of the Ministry of Economy, Trade and Industry and the energy industry.