Aggregator Fees in Japan Are Almost Entirely Non-Disclosed
RE100 Power, Shizen Energy (Shizen Connect), ENERES, JERA Cross, Digital Grid, Universal Ecology, MC Retail Energy -- most people in the industry can name the major aggregators, yet almost no one can accurately state each company's fee rates.
The reason is simple: RE100 Power is the only company that publicly discloses its fee rate.
"The aggregation service commission is 5% of market profit (net), with contract terms of either 1 year or 5 years. For those who choose a 5-year contract, no initial setup fee is required."
Source: RE100 Power press release (April 6, 2026) / Aggregation Service page
RE100 Power lists competitors on its website comparison table as "approximately 10% (negotiation-based)." If this is accurate, the typical aggregator fee in Japan can be estimated at around 5-15% of market profit. However, the definition of "market profit" is not standardized across companies. This is where the pitfall lies.
"Gross" vs. "Net" — How Definitions Create a Million-Yen Annual Difference
There are broadly two methods for calculating the base on which aggregator fees are applied.
| Calculation Base | Definition | Public Example |
|---|---|---|
| Gross (Total Revenue) | The total income earned from the market. The amount before deducting charging costs or penalties | Industry benchmark: 3-10% of total revenue (per Sympower public materials) |
| Net (Market Profit) | Profit remaining after deducting charging costs, wheeling charges, imbalance penalties, etc. from total revenue | RE100 Power: "5% of market profit" |
Even with the same "5%" fee rate, a different calculation base can nearly double the actual fee amount. Use the simulator below to compare results based on your own project parameters.
* The "Charging & Operating Cost Ratio" in the simulator includes JEPX electricity purchase costs, wheeling charges, generator-side levies, renewable energy surcharges, imbalance penalties, etc. Actual cost ratios vary significantly depending on operational patterns, area, and market prices.
How the Money Flows — Payment Flow Overview Across 3 Markets
To understand fee calculation bases, you first need to know how payments from each market reach the battery owner.
Balancing Market
Specified Wholesale
Supply Operator
After fee deduction
Wholesale Market
After fee deduction
Capacity Market
Owner or Aggregator
(1) Does that "revenue" include capacity market income?
(2) Are charging costs (JEPX electricity purchases) deducted before or after the fee calculation?
(3) Who bears imbalance penalties -- the aggregator or the owner?
(4) Is the EPRX transaction fee (0.06 yen/delta-kW per 30 min) separate or included?
International Contract Models — Alternatives Beyond Commission-Based Fees
In Japan, virtually all aggregator contracts are commission-based (revenue share), but internationally, contracts fall into five distinct models.
❶ Revenue Share (Commission-Based)
The aggregator optimizes the battery's charge/discharge cycles and receives a fixed percentage of market revenues as compensation. When the market performs well, the aggregator's take increases, aligning the incentive for revenue maximization with the owner. However, as this article explains, ambiguity in defining "what constitutes the base for that percentage" (gross vs. net) can lead to disputes.
Real estate analogy: Like a property management company saying "We'll take X% of the rent when tenants move in" -- same structure as a sublease arrangement.
❷ Floor + Revenue Share
The aggregator guarantees the owner a minimum annual revenue floor. When market revenues exceed the floor, the surplus is split between the owner and aggregator (typically 50:50). The owner receives a guaranteed income floor in exchange for a larger aggregator share during strong market years. In the UK, Statkraft signed a floor-price contract with Gresham House Energy Storage Fund covering 412MW of BESS, guaranteeing a total of £135M (approx. 27 billion yen) through September 2035 (equivalent to approximately £41,000-44,000 per MW per year).
Real estate analogy: "We guarantee X yen per month even if units are vacant. When fully occupied, we split the excess 50/50" -- a guaranteed sublease contract.
Source: Statkraft/Gresham House Energy Storage Fund contract (announced July 2025), Sympower public materials
❸ Tolling Agreement
The aggregator "leases" the battery's charge/discharge rights for a fixed period, paying the owner a fixed tolling fee. All market profits go to the aggregator, while the owner receives predictable fixed income regardless of market prices. The high revenue predictability makes project finance (bank lending) easier to arrange. In the UK, Octopus Energy signed a 2-year tolling agreement for 568MW of BESS with Gresham House Energy Storage Fund (per-MW rate undisclosed).
Real estate analogy: A full-building master lease. "We will pay you X million yen per year; in return, we handle all operations ourselves."
Source: Solar Power Portal (June 2024), Modo Energy, Aurora Energy Research
❹ Hybrid Contract (Partial Toll + Merchant)
The battery capacity is split, with a portion under a tolling arrangement (fixed income) and the remainder under a revenue share (market-linked). The fixed portion stabilizes cash flow while the variable portion captures market upside. Tesla signed a hybrid contract with Australia's Genex Power for a 50MW project, featuring a minimum guarantee plus revenue sharing (reportedly the first such arrangement in the industry).
Real estate analogy: In a 5-story building, floors 1-3 are under a master lease (fixed rent), while floors 4-5 earn percentage-based tenant fees. A structure designed to capture both stability and upside.
Source: Enspired blog, RenewEconomy Tesla/Genex Power contract reporting (Australia, 50MW Bouldercombe project)
❺ SaaS / Software License (Optimization-as-a-Service)
Rather than outsourcing operations to an aggregator, the owner pays a license fee (monthly or annual fixed subscription) for market-trading optimization software, while the owner (or a separate trader) makes charge/discharge decisions. This model is suited for operators with their own market trading expertise. In Japan, Shizen Connect offers both managed operation services and SaaS-based solutions.
Real estate analogy: Subscribing only to property management software while handling tenant recruitment and management entirely on your own.
In Japan, the revenue share model (❶) still overwhelmingly dominates. However, GridBeyond (Ireland-based) has begun offering floor + revenue share (❷) and tolling (❸) models in the US ERCOT and CAISO markets. The company has also entered the Japanese BESS operations market through its local subsidiary (GridBeyond GK). As Japan's battery storage market matures, the contract models that are becoming mainstream overseas (❷ and ❸) may increasingly become available options.
What Matters More Than Fee Rates — An Aggregator's "Skill" Can Mean Tens of Millions in Annual Difference
"Should I choose the company with a 5% fee or the one with 10%?" Many asset owners start with this comparison, but the order of priorities is backwards. The revenue difference caused by an aggregator's operational skill far exceeds the difference in fee rates.
UK Performance Data: 30% Revenue Gap in the Same Market
Modo Energy, a UK-based battery market analytics firm, compared revenues across all operational batteries in the UK during H1 2025. The results were as follows.
| Annual Revenue per MW | 2MW Equivalent (Reference) | |
|---|---|---|
| Top-performing BESS | £100,000+ (approx. 20M yen) | Approx. 40M yen |
| Overall average | £69,000 (approx. 13.8M yen) | Approx. 27.6M yen |
| Difference | £31,000+ (approx. 6.2M yen) | Approx. 12.4M yen |
* Converted at £1 = 200 yen. Excludes capacity market revenue. Source: Modo Energy "GB BESS: Why top-performing batteries earn 30% higher revenues" (July 2025)
Among batteries connected to the same UK electricity market and operating under the same regulatory framework, annual revenue differed by over 30%. Modo Energy's analysis showed that one top-performing battery (Jamesfield 2) achieved higher revenues despite 15% fewer charge/discharge cycles than the lowest performer. It was not earning more by cycling more frequently -- it was earning more through superior market price forecasting and trade timing.
US Texas Performance Data: 48% Revenue Gap from Optimization Differences
A similar trend is observed in the US Texas (ERCOT) market. Gridmatic analyzed 89 BESS units in 2024 and found that a single unit optimized by the company earned 48% more revenue than the overall average. While this is a single-unit case study, it demonstrates how the quality of optimization algorithms directly impacts revenue.
Applied to a 2MW/8MWh System in Japan
International data cannot be directly applied to Japan, but the structural reality that "aggregator operational quality drives 30-50% revenue differences" is the same. How many of the 48 trading slots result in successful awards, which time periods to bid into which market, how to optimize JEPX arbitrage timing -- these are all determined by the aggregator's decisions.
Below is a comparison of take-home amounts when selecting based on fee rate alone versus selecting based on operational capability.
| Aggregator A (Cheap but Average) | Aggregator B (Expensive but Excellent) | |
|---|---|---|
| Annual Gross Revenue | 70M yen | 100M yen |
| Charging & Operating Costs (40%) | -28M yen | -40M yen |
| Market Profit (Net) | 42M yen | 60M yen |
| Fee Rate (Net Basis) | 5% | 10% |
| Fee Amount | -2.1M yen | -6M yen |
| Owner Take-Home | 39.9M yen | 54M yen |
Aggregator B's fee rate is twice as high. Yet because its superior operational capability generates 30M yen more in annual gross revenue, the owner's take-home is 14.1M yen higher per year with B. Over 20 years, this amounts to approximately 280M yen. Selecting based on fee rate alone means missing this difference entirely.
The most important factor in selecting an aggregator is whether they can disclose past operational track records (annual revenue per MW, award rate, utilization rate). Fee rates can be negotiated, but operational capability is not easily changed.
March 2026 Market Reform — With a Shrinking Pie, Fee Negotiations Matter Even More
On March 13, 2026, the Balancing Market trading system underwent a major overhaul.
| Change | Previous System | New System |
|---|---|---|
| Trading Method | Weekly block bidding | Day-ahead trading (30-min slots) |
| Delta-kW Price Cap | 19.51 yen/delta-kW per 30 min | 15.00 yen (phasing down to 7.21 yen) |
| Bidding Frequency | Once per week | Daily, 2:00 PM deadline |
The price cap reduction directly shrinks the revenue pool from the Balancing Market. With a smaller pie, negotiating how much the aggregator takes from it has become even more critical than before.
At the same time, the shift to day-ahead trading has dramatically increased aggregator workloads. Bidding decisions that were once weekly are now daily, requiring 30-minute slot-level price forecasting and optimization. The gap in operational quality between aggregators with advanced algorithms and 24/7 operational capabilities and those without is likely to widen further.
5 Key Points to Verify Before Signing an Aggregator Contract
- Confirm the fee calculation base in writing — Is it "5% of market profit" or "5% of gross revenue"? Have the definition of "market profit" or "operating profit" (what is deducted before the calculation) explicitly stated in the contract
- Confirm the scope of fee application — Does it apply only to Balancing Market revenue, or also to JEPX arbitrage profits and capacity market income?
- Confirm who bears imbalance penalties — Who is responsible for penalties caused by the aggregator's system failures or dispatch errors?
- Confirm contract duration and termination conditions — Can you switch aggregators if market conditions change? What is the lock-in period?
- Demand operational track records — A low fee rate is meaningless if the award rate is also low. Verify whether the aggregator can disclose performance data from the past 12 months (revenue per MW, award rate, utilization rate)
To participate in the Balancing Market as an aggregator, registration as a "Specified Wholesale Supply Operator" under the Electricity Business Act is required. As of March 2026, 142 companies are registered. Additionally, starting from April 2027, IoT devices (PCS controllers) compliant with JC-STAR Level 1 are expected to become a requirement for grid interconnection. Whether the control equipment used by the aggregator is JC-STAR compliant is a verification point directly linked to business continuity beyond 2027.
Notes on Data
(1) Fee rates are the result of individual negotiations: The rates presented in this article are estimates based on publicly available information and will vary depending on project scale, contract duration, and battery specifications. We recommend obtaining quotes from multiple aggregators for comparison.
(2) International rates cannot be directly compared: Market structures, electricity price levels, and regulatory environments differ between Japan and other countries. European tolling rates (€110,000-150,000/MW/year) cannot be directly applied to Japan, but the contractual framework concepts are informative.
(3) Operational quality data is from international markets: Japan's grid-scale battery storage market is still in its early stages, and no domestic data quantitatively comparing operational quality across aggregators has been published. As the market matures, benchmarking services like Modo Energy may emerge in Japan as well.
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