A complete guide to EPRX's five balancing products: technical specs, price cap history (¥19.51 in 2021 to ¥15.00/¥7.21 in 2026), bidding schedules, and settlement mechanisms for BESS operators.
EPRX × BESS Series (Article 40–44)
Since its launch in 2021, the Japan Electric Power Exchange Balancing Market (EPRX) has become the most important ancillary service market in Japan's power system. For battery energy storage system (BESS) operators, a deep understanding of EPRX bidding rules, settlement mechanisms, and product characteristics is a prerequisite for revenue maximization.
| Product | Function | Response Time | Duration | Price Cap (¥/ΔkW) |
|---|---|---|---|---|
| Primary Reserve (GF) | Frequency control | Within 10 sec | 30 min | ¥15.00 |
| Secondary Reserve-1 (LFC) | Load following | Within 5 min | 30 min | ¥15.00 |
| Secondary Reserve-2 (EDC Fast) | Economic dispatch (fast) | Within 5 min | 30 min | ¥7.21 |
| Tertiary Reserve-1 (EDC Slow) | Economic dispatch (slow) | Within 15 min | 30 min | ¥7.21 |
| Tertiary Reserve-2 (Manual) | Planned adjustment | Within 45 min | 30 min | No cap |
| Period | Products | Price Cap (¥/ΔkW) | Background |
|---|---|---|---|
| April 2021 (Launch) | All products | ¥19.51 | Market creation, liquidity assurance |
| 2024 (Early reduction) | Secondary-2, Tertiary-1 | ¥7.21 | Phased reduction for slower products |
| March 14, 2026 (Revision) | Primary, Secondary-1 | ¥15.00 (▼23.1%) | Competition promotion, fair pricing |
EPRX settlement is based on "adjustment capacity (ΔkW) × cleared price," not actual generation (kWh). As long as a BESS maintains "availability," it earns capacity fees even without being dispatched.
A thorough understanding of EPRX product specifications, price caps, and bidding schedules forms the common foundation for building an optimal Offer Stack (Article 41), formulating capacity market composite strategies (Article 42), managing imbalance fee risks (Article 43), and constructing a complete financial model (Article 44).
Enter your BESS specifications (MW/MWh) and target products to instantly calculate annual EPRX revenue potential.
Open Calculator →EPRX × BESS Series (Article 40–44)
EPRX × BESS Series (Article 40–44)
Series Progress
Article 1 of 5
EPRX Bidding and Settlement Rules Complete Guide
This ArticleThis series provides an in-depth analysis of the complete BESS revenue pathway in Japan's electricity market, from EPRX rules to financial modeling.
Rules Foundation
Bidding Strategy
Capacity Market
Risk Management
Financial Model
免責聲明 / Disclaimer： Blog articles are for educational and reference purposes only and do not constitute investment advice.
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