"Electricity Resilience" Using Energy Storage Systems for ESS (Energy Storage Systems)

In Japan, which can be called a "disaster-prone country," securing a power supply in case of emergencies is a fundamental BCP measure. The term "electric power resilience" is used to describe the ability to recover from disasters, but many companies are unsure of what specific measures they should take.

This page introduces energy storage systems for ESS (Energy Storage Systems) as an example of corporate power resilience measures.

Why is electric power resilience so important for businesses, inspired by the Hokkaido blackout of 2018?

The Hokkaido Eastern Iburi Earthquake occurred on September 6, 2018. The seismic intensity of 7 was recorded in Atsuma Town, and the seismic intensity of 6+ was recorded in Abira Town, and Mukawa Town, Hokkaido. 17 minutes after the earthquake, the entire Hokkaido region was blacked out due to the collapse of the entire power transmission and distribution system.

Immediately after the earthquake, the power supply frequency temporarily dropped to 46.13 Hz due to the shutdown of turbines at the Tomatoh Atsuma Thermal Power Station (Units 2 and 4). With the emergency operation of the Hokkaido-Honshu HVDC Link started, the recovery trend turned toward 50Hz, but after that, the eastern Hokkaido area became an isolated system, and the hydroelectric power plant stopped due to the increase in frequency, and the Hokkaido-Honshu HVDC Link was in full operation. As a result, I could not afford it. Subsequently, the Tomatoh Atsuma Thermal Power Station (Unit 1) was shut down due to a damaged boiler tube. The supply-demand balance for the entire Hokkaido region began to collapse, causing power resilience to deteriorate, resulting in the blackout.

Thus, the unprecedented all-province blackout was caused by a combination of multiple factors, including the shutdown of wind and hydroelectric power plants due to a drop in frequency and rapid recovery, and a broken boiler tube at the Tomatoh Atsuma Thermal Power Station (Unit 1).

It took 45 hours from the blackout to the restoration of power supply in Hokkaido.

In the event of a power outage in a small area in general, the power is restored in a stable manner by receiving a temporary supply of power from an external grid. However, in order to restore power after a total system blackout of the dispatch power system, it is necessary to start supplying power from a power plant equipped with a black start function (a facility that generates power to resolve the blackout without receiving power from an external power source).

In this case, stable restoration was achieved by starting operation from the Takami and Niikappu power plants, which are pumped storage power plants with a black start function.

At pumped storage power plants, water for power generation is pumped upstream and stored in upstream reservoirs (dams) during the nighttime when there is a relatively large surplus of electricity demand. Pumped-storage hydroelectric power generation uses the energy generated when water stored upstream is released downstream to generate electricity. The mechanism is similar to that of hydropower generation, but unlike hydropower generation, which is one-way (water simply flows from upstream to downstream), pumped-storage hydroelectric power generation is bidirectional (water is stored upstream and then repeatedly discharged downstream).

Pumped storage power plants are used to stabilize the power grid during normal times to prevent power shortages even if demand for electricity temporarily increases, and are sometimes used as a black start function during emergencies, contributing to the enhancement of power resilience.

Pumped storage power generation can be utilized as a power source for black start. However, the number of pumped storage power plants is too small to ensure stable power supply for the entire region due to the need for vast land, equipment, cost, and time.
The solution is the ESS (Energy Storage System) , which combines storage batteries and grid-connected inverters. ESSs are compact, quick, and inexpensive to install compared to pumped storage systems, because they have the same functions as pumped storage systems.In other words, the ESS provided by ENAX is a system that can realize "power resilience measures" with a black start function.

The energy storage system for ESS, which is connected to the power supply infrastructure grid, is capable of instantaneous charge/discharge response to charge/discharge commands from the upper side. For example, when performing power peak shaving to control contracted electricity rates, if the amount of electricity used is about to exceed a set value, the system instantly discharges the excess electricity. In the event of a power outage, the storage battery system for ESS will discharge electricity to important loads from the moment it detects a power outage, and supply electricity from the storage batteries at the same time as the power outage occurs, preventing electricity interruptions and enabling power resilience measures even during disasters.

In June 2020, the Energy Supply Resilience Act was enacted to ensure the resilience of electric power infrastructure. ENAX's energy storage system for ESS is the perfect solution to secure power for BCP in the event of power outages due to natural disasters such as earthquakes, typhoons, heavy rain, heavy snow, and lightning strikes.

Today, the unstable global situation is causing electricity bills to skyrocket, but the use of energy storage systems for ESS can help factories and business establishments reduce their electricity consumption by cutting power peaks. When people hear the phrase "power resilience measures," they may ask, "Isn't it necessary to install large-scale power generation equipment?" "Isn't it difficult without cooperation with power companies, power plants, etc.? However, there are a variety of measures that can be implemented at individual offices and factories. If you have any questions about power resilience, please feel free to contact us at ENAX.

For more information, please see "Research and Development".