Storage Orders in SDAC: A Public Consultation on a New Day-Ahead Order Type
European NEMOs (Nominated Electricity Market Operators) and TSOs (Transmission System Operators), working under the Market Coupling Steering Committee (MCSC), opened a public consultation on a proposed storage order for the Single Day-Ahead Coupling market (SDAC). They published it on 1 June 2026 and will collect responses until 14 July 2026. The order type would let systems that buy and sell electricity within the same day, such as batteries and hydro pumped storage, bid in the day-ahead auction according to their operating constraints. The proposed go-live is the fourth quarter of 2027.
A new order type for storage in SDAC
The storage order is a new bid format for the day-ahead auction. It came out of the Research and Development stream around EUPHEMIA, the algorithm that clears SDAC across coupled European markets. It supports systems that both buy and sell energy within the same day.
The consultation document names batteries and hydro pumped storage as the technologies considered, and keeps the design agnostic to the underlying technology: any system that can switch between consumption and production across the market's time units can bid with it. The day-ahead market runs on 15-minute market time units (MTUs), so the asset must be able to operate across MTUs, including switching between consumption and production.
Why the current order types fall short for storage
Storage needs a stronger and more flexible link between periods than the existing toolkit provides. SDAC today runs on order types built around generation and consumption. A generator offers volume at a price for a given period, and a consumer bids to buy.
A storage asset does both, and the value of charging in one period depends on the price at which that link later discharges. An operator approximates it by combining block orders and other formats and by building a price forecast for the full delivery day, which adds modelling work and ties the bid to forecast quality.
How the storage order would work
The storage order aims to shift part of the intertemporal optimisation from the participant's bidding strategy into the clearing algorithm. The algorithm allocates the order across all day-ahead MTUs: the operator submits the asset's parameters, and the charge and discharge schedule follows from the prices the auction computes for the day. The consultation document describes a set of core parameters, including maximum energy stored (MWh), maximum input power (MW), maximum output power (MW), and cycling costs (€/MWh). It also discusses additional parameters, such as starting energy stored, minimum energy stored, efficiency, and a value for energy left in store at the end of the day.
The stated aim is to let participants optimise storage bidding with less reliance on a detailed forecast. According to the consultation document, the order is designed to avoid loss-making outcomes across the auction's MTUs. The document presents this as a design property rather than a tested outcome.
Aggregation: how storage orders reach the auction
A single storage order can represent several storage systems. The consultation document explains that the clearing algorithm performs better when systems are grouped, so one order may cover multiple assets. The proposal sets a minimum order size, currently either 5 MW or 25 MW, with the final figure left to the consultation. Systems above the threshold can be submitted as a single order, which suits hydro pumped storage and large batteries. Smaller systems have to be aggregated to exceed the minimum, either by the participant within a bidding zone or by the NEMO. The document outlines a potential approach where NEMOs could offer predefined parameter sets ("baskets") for aggregation, with de-aggregation of the cleared results afterwards.
Open points in the consultation
Several design choices remain unresolved, which is the reason for putting them to the market. The minimum order size is not fixed, and the document presents 5 MW and 25 MW as the current options. The basket values that smaller participants would select are still to be determined. Aggregation carries a trade-off, since a small asset loses the granularity of an individual order once it sits inside an aggregated order or a basket. The document also notes that its assumptions rest on the simulations run so far, so the parameters and the aggregation approach may change before the specification is final.
Consultation timeline and participation
The consultation opened on 1 June 2026 and closes on 14 July 2026, end of day. An information document and a questionnaire sit on the NEMO Committee website, and a webinar on 16 June 2026 walked participants through the questions. Storage operators, traders, exchanges, and other SDAC stakeholders submit responses through the official questionnaire and send questions to the MCSC communication contact named in the materials. Individual answers stay anonymous and are not published.
What the proposal could mean for market participants
For operators of batteries, hydro pumped storage, and other same-day buy and sell systems, a dedicated order type would change the route to the day-ahead market. Rather than translating a dispatch plan into existing order types, an operator would submit the asset's parameters and let the auction set the schedule. The consultation gives these operators, and the traders who route battery storage to market, a window to test the design against their own systems and to comment on the open points before the proposed 2027 go-live. Those open points include the minimum order size and the aggregation model.
Where the storage order sits among day-ahead, intraday, and balancing markets
The consultation document limits the storage order to the day-ahead market, so its questions refer to that timeframe. Storage assets earn revenue across several timeframes. They trade in the intraday market, where positions adjust closer to delivery, and many provide balancing and ancillary services. The day-ahead auction sets a reference schedule and price for the following day. The proposal does not directly change the intraday or balancing arrangements that storage participants use today.
Key terms
- SDAC (Single Day-Ahead Coupling) couples European day-ahead electricity markets so that one algorithm matches supply and demand across bidding zones and allocates cross-zonal capacity.
- NEMO (Nominated Electricity Market Operator) is a power exchange authorised to operate day-ahead and intraday coupling in one or more bidding zones.
- TSO (Transmission System Operator) operates the high-voltage transmission grid and provides the cross-zonal capacity used in market coupling.
- MCSC (Market Coupling Steering Committee) is the body of operators that governs the joint operation and development of European market coupling.
- EUPHEMIA is the algorithm that supports the market coupling calculation and clears the SDAC auction across coupled markets.
- MTU (Market Time Unit) is the bidding and settlement interval of the day-ahead market, currently 15 minutes.
- Storage order is the proposed order type that lets a storage system express its operating constraints in the day-ahead auction.
Frequently asked questions
What is the storage order in SDAC?
It is a proposed order type for the Single Day-Ahead Coupling market that lets systems which both charge and discharge within the same day, such as batteries and hydro pumped storage, bid according to their operating constraints rather than through combinations of existing order types.
Why is a new order type being proposed?
Existing SDAC order types were built around generation and consumption and do not carry the link between charging and discharging periods that a storage asset needs. The proposed order moves that logic into the clearing algorithm so operators rely less on a detailed price forecast.
Which assets can use the storage order?
Any system that can buy and sell energy within the same day. The consultation document names batteries and hydro pumped storage as the technologies considered, and keeps the design agnostic to the underlying technology.
What is still undecided?
The minimum order size (5 MW or 25 MW), the basket values for smaller participants, and the final aggregation approach remain open and form part of the consultation.
When does the public consultation close?
The consultation closes on 14 July 2026, end of day, after opening on 1 June, according to the consultation page.
When would the storage order go live?
The proposed go-live is the fourth quarter of 2027.
Who is running the consultation?
European NEMOs and TSOs under the Market Coupling Steering Committee (MCSC) are running it.
Source
NEMO Committee, "Public Consultation: Storage Orders in SDAC," available at nemo-committee.eu.
Disclaimer
This article is prepared by D.TRADING for general informational purposes only and does not constitute legal, financial, investment, accounting, tax, or regulatory advice. The information contained herein is based on publicly available sources and reflects opinion on the regulatory environment as of the publication date. D.TRADING makes no representations or warranties, express or implied, as to the accuracy, completeness, or timeliness of the information provided. This document is not an offer or solicitation to buy or sell any energy products, commodities, or financial instruments.
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