Niterra Co., Ltd.

Announcement of Development of a Compact Reversible SOC System
Capable of Hydrogen Production and Power Generation

NAGOYA, JAPAN, March 27th, 2024 — Niterra Co., Ltd. (hereafter the Company), Japan’s leading spark
plug and ceramics manufacturer with an evolving portfolio focused on ceramics and beyond, hasannounced the development of a “reversible SOC (Solid Oxide Cell) system" using the SOC they alreadyhave under development. This SOC system combines hydrogen production by steam electrolysis andpower generation by fuel cells in a single-cell stack.
◆Background of the Development
In recent years, renewable energy-derived electricity has been increasingly introduced to realize acarbon-neutral society. However, as the percentage of renewable energy in society increases, further
curtailment of surplus power output is expected to increase, making using surplus power a social issue.
One solution to this problem is to convert surplus electricity into hydrogen, store it, and use the storedhydrogen to generate electricity in the event of power shortages or power outages during disasters. To
address this issue, we have applied our fuel cell technology to develop a "reversible SOC system" thatenables hydrogen production through steam electrolysis and power generation through a fuel cell with asingle cell stack.

◆Features and Functions of the System
Our cell stacks can operate in two ways: SOEC, which uses electricity to generate hydrogen, and SOFC,
which uses hydrogen and air to generate electricity. Neither of these technologies emit CO₂ or othergreenhouse gases and are essential for achieving carbon neutrality. Since a single stack can switch
between hydrogen production and electricity generation, the system can be more compact than acombination of SOEC and SOFC, with advantages such as a smaller footprint.
In SOC systems, a cell stack must be maintained at a high temperature of around 700 °C, andmanagement of this thermal energy dramatically affects the efficiency. This system is equipped with acompact, high-efficiency hot module*1 that can effectively utilize heat generated internally and utilizes
technologies for controlling electrochemical properties of the cell stack in high-temperature environments
and thermo-fluid analysis technologies that we have developed over many years.

◆System Usage Scenes
By combining photovoltaic power generation, which has large seasonal fluctuations in power generation,with a hydrogen storage system, it is possible to adjust the supply and demand of electricity between
seasons by using SOEC to convert and store surplus power in summer into hydrogen and using SOFC
power generation with hydrogen stored in summer to make up for any power shortages in winter.
The SOC system can also be an emergency power source since it can generate electricity anytime using
stored hydrogen and flexibly supply energy day and night. SOC systems can also be offered as anemergency power source.

◆Future Prospects
We will verify the system as an energy management system while conducting a demonstration in fiscalyear 2024. During the demonstration, we plan to obtain durability and operation results in combination
with a hydrogen storage system while making improvements to increase the conversion efficiency of theSOC system, In addition, we will conduct educational activities to promote the use of SOC systems insociety, search for collaborative partners, and aim to commercialize the system by the end of fiscal year2025.
In the SOC business, we aim to become a leading company that can provide cell stacks, hot modules,and systems to a wide range of customers and contribute to building a sustainable society.
*1: A hot module is a structure consisting of a cell stack, heat source, gas piping, and insulation material. It is capable ofraising the temperature of the cell stack to around 700°C with high efficiency and maintaining the high temperature.
*2: Figures measured at the electrode end of the hot module.
*3: Percentage of power remaining when the power used for hydrogen conversion by SOEC is set to 100% and thehydrogen is converted back into electricity by SOFC.

About Niterra
Founded in Nagoya, Japan in 1936, Niterra Co., Ltd. (formerly NGK Spark Plug Co., Ltd.) is renowned for its
NGK-branded spark plugs and NTK-branded ceramic products. Niterra, a coined word combining the Latinwords "niteo" (shine) and "terra" (Earth), was introduced in April 2023 to express the reborn company's
commitment to sustainability through an evolving portfolio focused on ceramics and beyond. Under thecorporate message "IGNITE YOUR SPIRIT," Niterra is now expanding into the growth fields of mobility,healthcare, environment and energy, and communications. The company's consolidated revenues in fiscal
2022(to March 2023) totaled 562.6 billion yen (4,167 million USD). Niterra has 33 bases in Japan and 59
overseas, and more than 16,000 employees worldwide. Please visit https://www.ngkntk.co.jp/english/