Japan’s major market changes coming in April and October 2026

Key changes in the balancing market 

Shift to shorter trading horizons: All balancing products, previously traded on a weekly basis, will move to day-ahead procurement with 30-minute market unit. This aligns with European-style ancillary service markets and enhances flexibility for market participants. 

Expanded participation: Low-voltage resources such as household batteries and EVs will be allowed to join the market, provided device-level measurement is in place. This opens the door for distributed energy resources to play a bigger role in grid stability. 

Price cap adjustments: METI plans to lower the price cap for combined products to JPY 7.21 (ΔkW/30 mins), down from JPY 19.51(ΔkW/30 mins). While intended to curb excessive settlement costs, this could discourage participation if spot prices remain high, raising concerns about liquidity and potential withholding strategies. 

Imbalance price cap increase starting from FY2026 

• (C-value; reserve margin below 3%) Increased from 200 yen/kWh to 300 yen/kWh
• (D-value; reserve margin below 8%): Revised to 50 yen/kWh, with Okinawa applying the same rule.  

Intraday market transparency from October 2026 

In addition to the anticipated reform in the balancing market system, JEPX will publish intraday bid information grouped into five regional zones: 

• Hokkaido
• Tohoku & Tokyo
• Chubu, Hokuriku & Kansai
• Chugoku & Shikoku
• Kyushu 

This five-zone approach strikes a balance between transparency and confidentiality, mitigating risks of exposing short-run marginal costs (SRMC) while giving market players better visibility for imbalance management. 

JEPX system revision 

According to JEPX’s latest release, published on 26 November 2025, the spot and intraday trading system will fully migrate to a new API-based platform, the former in April 2026 and the latter in October 2026, eliminating the existing GUI interface. As a result, participants should prepare for: 

• Server-to-server communication instead of manual bidding
• Retraction of fee revisions: Despite the previously announced plans to revise fees in April this year, membership fees, as well as spot and intraday transaction fees, will remain unchanged for FY2026 at JPY 30/MWh (spot) and JPY 100/MWh (intraday).

Implications for market players 

The move to shorter intervals and day-ahead clearing will increase operational complexity, requiring more advanced forecasting and bidding strategies create opportunities for flexibility providers, with battery storage operators and EV aggregators particularly well positioned to benefit.