JEPX spot trading
On the JEPX trading screen you submit and monitor bids on the JEPX day-ahead (spot) market for all eligible assets in the workspace. Open it from the side navigation under Revenue > JEPX. Bid volumes come directly from the Tensor optimization model, and you can edit individual bids before submission. Tensor Cloud sends the bids to JEPX through the API integration and retrieves the results automatically once the auction clears.
Tensor sets up the JEPX API integration for each workspace, and JEPX has to approve it manually. Before using this screen, contact us with the Get support button in the top navigation bar. We will guide you through the registration and verify the delivery contract code on file for your workspace.
Selecting a delivery date
Use the date picker in the top right of the screen to choose a delivery date. The arrows next to the picker (or the K and J keys) move to the previous or next day. You can submit bids from up to ten days ahead until 10:00 JST on the day before delivery, the JEPX deadline for the spot market. After the deadline, the Place bids button no longer appears for that date. Past dates show the final results (clearing prices and confirmed volumes), so you can use the same screen to audit any earlier day.
Spot tab
The Spot tab is the main view. It lists the 30-minute slots with bid activity for the selected delivery date, grouped by grid area. If no asset in the workspace qualifies for JEPX trading, the tab shows No qualified assets in this workspace instead.
Grid area sections
Bids on JEPX are placed per grid area. When you have several battery assets in the same area, their charge and discharge volumes are aggregated into a single bid per slot. Each grid area appears as its own collapsible section with a status summary next to the area name:
- A count of bids for each status present in the area, for example 12 Contracted or 2 Partially contracted
- No bids, when there are no bids for the date yet
The View history button next to each area name opens the History tab filtered to that area. The Place bids button opens the bid dialog for that area (see Submitting bids).
Bid table
Expanding a grid area shows one row per slot with bid activity:
| Column | Description |
|---|---|
| Slot | 30-minute delivery slot (for example, 09:30–10:00) |
| Type | Sell (discharge) or Buy (charge) |
| Status | Current state of the bid (see Statuses) |
| Bid volume (MW) | Volume submitted to JEPX |
| Bid price (JPY/kWh) | Limit price submitted to JEPX |
| Confirmed volume (MW) | Volume contracted at the auction, once results are in |
| Market price (JPY/kWh) | Clearing price for the slot, once results are in |
| Submitter | The user who triggered the submission, or System for automated retrievals |
| Updated at | Time of the most recent change to the slot |
Slots with no bid activity do not appear in the table. On narrow screens, the Submitter and Updated at columns are hidden. Each row's action menu has a View history item that opens the History tab filtered to that slot.
Slot detail panel
Click a slot row to open a detail panel on the right. The panel shows the slot's current bid values, the submitter, and the full change history with timestamps, so you can check what was submitted for the slot, when, and by whom. The history includes, for example, the moment the slot moved from Submitted to Contracted after the auction cleared.
Submitting bids
Bids are submitted per grid area. Click Place bids next to the area to open the bid dialog (New JEPX bid, or Edit JEPX bid if bids already exist for the date). The dialog lists all 48 slots of the delivery day, each with a sell row and a buy row:
| Column | Description |
|---|---|
| Slot | 30-minute delivery slot |
| Type | Sell or Buy |
| Plan volume (MW) | Volume from the generation plan (new bids only) |
| Previous bid volume (MW) | Volume of the existing bid (when editing) |
| Bid volume (MW) | Volume to submit, prefilled from the generation plan. When editing, labeled Latest bid volume (MW) and prefilled from the latest generation plan |
| Bid price (yen/kWh) | Limit price to submit |
The Hide zero rows toggle, on by default, hides rows where both the reference and bid volumes are zero. Click Submit bids to JEPX to submit.
By default, bid volumes come from the Tensor optimization model for the selected delivery date, and the limit prices guarantee execution:
- Sell bids (discharge slots): SELL-LIMIT at 0.01 JPY/kWh, the minimum price allowed on JEPX.
- Buy bids (charge slots): BUY-LIMIT at 200 JPY/kWh, the maximum price allowed on JEPX.
With these prices, both sell and buy bids always trade at the JEPX clearing price for the slot.
When you submit, Tensor Cloud sends the full set of slots for the grid area and delivery date to JEPX in a single operation. Volumes are rounded down to the JEPX minimum bid unit of 0.1 MW. A slot with a bid volume of zero is not bid, and an existing bid for that slot is deleted. The status of each affected slot changes to Submitted, and once the auction clears (around 10:10 JST for next-day delivery), the platform automatically retrieves the results and moves each slot to Contracted, Partially contracted, or Rejected.
Buy bids require an internal demand balancing group in the grid area, with at least one assigned asset whose battery can charge from the grid. Otherwise the submission is rejected with an error message.
Manual overrides
To deviate from the model's plan for a slot, edit the bid volume and bid price in the bid dialog before submission. Prices are limited to the JEPX range of 0.01 to 200 JPY/kWh. Manual entries override the model's output for the affected slot on the selected delivery date.
Resubmitting after re-optimization
If the Tensor optimization model produces a new plan after you have already submitted bids, you can resubmit at any time before the JEPX deadline. Click Place bids again: the dialog shows the previous bid volumes next to the latest planned volumes and keeps the previous bid prices. Resubmission replaces the area's bids for the delivery date on JEPX in a single operation. Every earlier submission stays visible in the slot detail panel and on the History tab.
Automatic trading
When Autopilot is enabled for your workspace, Tensor Cloud submits your JEPX day-ahead spot bids for you once a day, every day including weekends and holidays. The daily run starts at 08:01 JST and submits bids for the next delivery day (D+1), ahead of the 10:00 JST gate closure. Bids are generated from the latest forecasts and the optimization model for each enabled grid area and trade at the market clearing price, using the limit prices described under Submitting bids. Autopilot submissions appear on this screen attributed to System.
Enabling Autopilot
Autopilot is configured per workspace in the JEPX integration settings: an Enable autopilot master switch and a Grid areas to auto-submit selection. Autopilot submits for a grid area only when both the master switch and that area are enabled, so you can automate some areas and keep others manual. The JEPX integration must be active (Tensor provisions your Member ID), and each auto-submitted area needs a registered delivery contract code. An enabled area without one is not submitted until a code is added.
Manual and automatic
When Autopilot is on, an Autopilot chip (or Partial autopilot when only some grid areas are enabled) appears next to the tabs, with a link to the settings. Each auto-submitted grid area is marked with an Autopilot icon next to its name.
In grid areas where Autopilot is enabled, you cannot submit bids manually on this screen. To take an area back, turn its Autopilot off, and manual submission is available again immediately. The manual editing, overrides, and resubmission described above apply to the areas you run manually.
What it submits
For each enabled grid area, Autopilot reads the optimization model's generation plan for the delivery day and places a sell bid for the planned generation in each 30-minute slot, with the volume floored to the JEPX minimum lot of 0.1 MW (50 kWh). Where the plan charges batteries from the grid, it also places a buy bid for the planned charging volume, grossed up for grid losses and rounded up to the lot size. Buy bids follow the same demand balancing group requirement as manual buy bids. Slots with nothing to trade are left unsubmitted. It submits once per day per area and does not resubmit through the day.
Notifications
You receive an in-app notification and an email only if a submission could not be completed before the gate closure. Successful submissions send no notification. A run can also be skipped without an error: when Autopilot is off for the area, when no delivery contract code is registered, or when there is nothing to trade that day. Autopilot submits bids on your behalf, but you remain responsible for your JEPX trading.
Statuses
A bid moves through the following states:
| Status | Meaning |
|---|---|
| Pending | Bid exists in Tensor Cloud but has not been submitted to JEPX yet |
| Submitted | Bid has been sent to JEPX and accepted into the auction |
| Contracted | JEPX has cleared the bid in full at the auction clearing price |
| Partially contracted | JEPX has cleared the bid for less than the submitted volume |
| Rejected | The bid did not clear at the auction |
| Failed | The bid could not be submitted to JEPX |
Type badges next to the status indicate Sell or Buy.
History tab
The History tab lists every change to bids for the selected delivery date, newest first. Each entry shows the slot, type, grid area, the change itself (for example, Submitted → Contracted 1.5 MW @ 12.34 JPY/kWh, with the contracted volume and clearing price), the actor who made the change (a user or System for automated retrievals), and when it happened.
Use the filters on the left to narrow the list:
- Slot: restrict to a single delivery slot
- Area: restrict to a single grid area
- Type: sell or buy
- Change type: creation, deletion, status change, or value change
The count next to each filter option shows how many changes match for the selected date. Filters combine with AND: selecting Sell and Status change, for example, returns only status changes on sell bids.