Efforts towards decarbonization and carbon neutrality are accelerating around the world.
The widespread use of renewable energy is key to this, but fluctuations in power generation, which are easily affected by weather and time of day, pose a challenge.
Storage batteries are now attracting strong attention as a technology that can solve this issue and realize a stable, energy-self-sufficient society.

This article introduces the roles of renewable energy and storage batteries, the latest technological trends, and examples of their implementation by companies and local governments.

1. The Need for Carbon Neutrality and an Energy Self-Sufficient Society

Carbon neutrality refers to achieving virtually zero greenhouse gas emissions and absorption.
Japan has set a goal of achieving carbon neutrality by 2050, and is expanding the use of renewable energy sources (such as solar, wind, and hydropower).

However, renewable energy alone faces the following challenges:

• Power generation is dependent on weather and time of day (excess during the day, shortage at night, etc.)
• Utilizing surplus power and backing up during power outages are difficult
• Regional supply and demand balances need to be stabilized

A system is needed to absorb these fluctuations and ensure stable and efficient energy use, and storage batteries play a central role in this.

2. The Evolution and Role of Battery Technology

① Stable Power Supply
Batteries can temporarily store electricity generated by solar and wind power and supply it during times of high demand or at night.
This helps smooth out fluctuations in renewable energy and stabilize the power supply.

② Peak Shifting and Electricity Bill Reduction
Charging during times when electricity rates are low and discharging during times when rates are high can reduce costs.

③ Backup Power Sources in the Event of Power Outages and Disasters
High-capacity batteries allow lifelines and important facilities to operate even during natural disasters and power outages.

④ Integration with Electric Vehicles (EVs)
Vehicle-to-Home (V2H) technology allows EVs to function as mobile storage batteries, supplying electricity to homes and offices.

3. Types of Storage Batteries

• Lithium-ion batteries: The current mainstream. High efficiency and long life. Widely used in homes and industrial applications.
• NAS batteries (sodium-sulfur batteries): Suitable for large-scale energy storage and capable of long-term discharge.
• All-solid-state batteries: Under development as a next-generation technology. Expected to improve safety and energy density.

4. Case studies in businesses and local governments

① Corporate case study: Utilizing renewable energy in factories and offices

• A major manufacturing company installed solar power generation and storage batteries, creating a system that generates 40% of its electricity through in-house power generation.
• It keeps production lines running even during power outages, making it an effective BCP (Business Continuity Plan) measure.

② Local Government Example: Installation at Disaster Prevention Bases

• Local governments install large-capacity storage batteries in public facilities.
• In combination with solar power generation, it enables the operation of lighting, heating, cooling, and communication equipment in evacuation shelters during disasters.

③ Commercial Facility Example: Reducing Electricity Bills through Peak Cuts

• Using storage batteries to reduce consumption during periods of high demand.
• In some cases, electricity bills have been reduced by tens of millions of yen per year.

5. Future Outlook for an Energy Self-Sufficient Society

Popularization of Distributed Energy Systems
→ Smart grids that can complete power generation, storage, and consumption in each region will progress

Reducing the Cost of Renewable Energy and Storage Batteries
→ Lower battery prices and expanded subsidy programs will make their introduction easier

Expanding “Green Power Trading” Derived from Renewable Energy
→ Systems that allow companies to share zero-CO₂-emission electricity are becoming widespread

Summary

Achieving carbon neutrality requires not only the widespread use of renewable energy but also the widespread use of storage batteries.

If an “energy self-sufficient society” in which households, businesses, and local governments generate, store, and use their own electricity becomes more widespread, it will simultaneously reduce energy costs, reduce environmental impact, and strengthen resilience in the event of a disaster.

The key to building a sustainable society of the future lies in smart energy systems that combine renewable energy and storage batteries.